Method for trench isolation for thyristor-based device

• US 6,818,482 B1
• Filed: 10/01/2002
• Issued: 11/16/2004
• Est. Priority Date: 10/01/2002
• Status: Expired due to Fees

• Current Assignee: T-Ram, LLC
• Original Assignee: T-Ram, Inc.
• Inventors: Horch, Andrew, Robins, Scott
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): MALSAWMA, LALRINFAMKIM HMAR
• Application Number:
  US10/263,370
• Time in Patent Office: 777 Days
• Field of Search: 438/133, 438/135, 438/137, 438/138, 438/268, 438/270, 438/272
• US Class Current: 438/138
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/763 Polycrystalline semiconductor regions H01L21/76264 takes precedence
• CPC Class Codes: H01L 27/0817 Thyristors only
• CPC Class Codes: H01L 29/41716 Cathode or anode electrodes for thyristors
• CPC Class Codes: H01L 29/66363 Thyristors
• CPC Class Codes: H01L 29/749 with turn-on by field effect

Abstract

A semiconductor device includes a thyristor body having at least one region in a substrate. According to an example embodiment of the present invention, a trench is in a substrate and adjacent to a thyristor body region in the substrate. The trench is lined with an insulative material and further includes conductive material that is insulated from the thyristor body region in the substrate by the liner material. A conductive thyristor control port is located in the trench and adapted for capacitively coupling to the thyristor body region in the substrate and to control current in the thyristor body by causing an outflow of minority carriers in the thyristor. With this approach, conductive material can be used to fill a portion of the trench while using the trench portion including the conductive material to electrically isolate a portion of the thyristor body in the substrate. This approach is particularly useful, for example, in high-density applications where insulative trenches having high aspect ratios are desired.

Claims

1. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench, separate from said conductive material that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port results in an outflow of minority carriers from said one thyristor body region and switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body.

2. The method of claim 1, further comprising forming a dielectric material for the control port on a sidewall of the trench, prior to forming the conductive thyristor control port.

3. The method of claim 2, further comprising forming in the substrate a base portion of a thyristor body region to which the control port is configured and arranged to capacitively couple.

4. The method of claim 1, wherein forming the conductive material in a portion of the lined trench includes forming the conductive material over the control port.

5. The method of claim 1, wherein forming the control port includes shorting the control port to the conductive material and wherein forming the insulative liner includes forming an insulative liner adapted to prevent the shorted conductive material from switching a portion of the thyristor body region in the substrate adjacent to the conductive material between a blocking state and a conducting state.

6. The method of claim 1, wherein forming a conductive material includes shorting the conductive material to a conductor in the semiconductor device in a manner that maintains the conductive material at a voltage level of the conductor.

7. The method of claim 1, wherein forming a conductive material in a portion of the lined trench comprises:

filling the lined trench with conductive material; and

removing a portion of the conductive material.

8. The method of claim 1, wherein providing a trench in the substrate includes etching the substrate.

9. The method of claim 1, wherein forming a conductive material in a portion of the lined trench includes forming polysilicon.

10. The method of claim 1, wherein providing a trench in the substrate includes providing a trench having a height to width aspect ratio greater than 2:

1.

11. The method of claim 1, wherein forming a conductive material in the trench includes depositing a conductive material adapted to fill a trench having a height to width aspect ratio greater than 2:

1.

12. The method of claim 1, wherein forming a conductive material in the trench includes depositing a conductive material adapted to fill a trench having a height to width aspect ratio greater than 4:

1.

13. The method of claim 1, wherein providing a trench in the substrate adjacent to a thyristor region includes providing a trench that extends at least partially laterally around the thyristor region.

14. The method of claim 13, wherein forming a conductive thyristor control port includes forming a conductive thyristor control port that at least partially surrounds the at least one thyristor body region in the substrate.

15. The method of claim 14, wherein forming the conductive thyristor control port includes forming a conductive thyristor control port that surrounds at least two opposite sides of the at least one region in the substrate.

16. The method of claim 14, wherein forming the conductive thyristor control port includes forming a conductive thyristor control port that sufficiently surrounds the at least one body region in the substrate such that it changes the potential across a majority of a cross-section of the at least one region in the substrate when a voltage is applied to the control port.

17. The method of claim 1, wherein forming the conductive thyristor control port includes forming a conductive thyristor control port that is configured and arranged for capacitively coupling pulses to the thyristor body for providing primary control for switching the thyristor between a stable current-blocking state and a stable current-passing state.

18. The method of claim 1, wherein forming the conductive thyristor control port includes forming a conductive thyristor control port that is configured and arranged for capacitively coupling to the thyristor body for changing the potential across a majority of a cross-section of the at least one thyristor body region in the substrate.

19. The method of claim 1, wherein forming conductive material in a portion of the lined trench includes forming a conductive material that is not adapted to electrically couple to the thyristor.

20. The method of claim 1, wherein forming the conductive material includes forming sufficient conductive material to offset the control port from a region of the thyristor body in the substrate.

21. The method of claim 1, wherein forming the conductive thyristor control port includes forming a conductive thyristor control port recessed below an upper surface of the substrate, further comprising:

forming insulative material in the trench and over the conductive thyristor control port; and

planarizing the insulative material in the trench and over the conductive thyristor control port.

22. The method of claim 1, wherein providing a trench in the substrate laterally adjacent to said at least one region in the substrate includes forming a nitride etch stop on an upper surface of the substrate and using the nitride etch stop to prevent the substrate from being etched while etching the trench.

23. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a dielectric material for the control port on a sidewall of the trench and then forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body; and

prior to forming the dielectric material, removing a portion of the insulative liner, wherein forming the dielectric material includes forming a dielectric material where the insulative liner has been removed.

24. The method of claim 23, further comprising removing at least a portion of the conductive material, after removing a portion of the insulative liner and prior to forming the dielectric material.

25. The method of claim 23, wherein removing a portion of the insulative liner includes etching the insulative layer while using the conductive material to prevent a portion of the insulative liner from being etched.

26. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

removing a portion of the conductive material, then forming a dielectric material for the control port on a sidewall of the trench, and then forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body.

27. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate, and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming the control port in a portion of the trench includes forming the control port over the conductive material.

28. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming the conductive material in a portion of the lined trench includes forming the conductive material over the control port; and

ion implanting a portion of the semiconductor device while using the conductive material over the control port to inhibit the ion implant from implanting the control port.

29. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein providing a trench in the substrate includes providing a trench extending into a well portion of the device, the well portion including a base portion of the thyristor region;

forming a first emitter region below the trench;

implanting a first base region in the thyristor body region in the substrate and adjacent to a first portion of the trench;

implanting a second base region in the thyristor body region in the substrate over the first base region and adjacent to a second portion of the trench; and

forming a second emitter region coupled to the second base region.

30. The method of claim 29, further comprising:

forming a pass device having first and second source/drain regions separated by a channel and a gate over the channel, the gate being adapted to switch the pass device between a blocking state and a conducting state in response to a voltage being applied thereto; and

electrically coupling the second emitter region to one of the source/drain regions.

31. The method of claim 29, wherein implanting a first base region includes implanting a first implant region below and adjacent to a bottom portion of the trench, prior to forming the first emitter region, wherein forming the first emitter region includes forming the first emitter region in the first implant region below the trench, a remaining portion of the first implant region forming the first base region.

32. The method of claim 31, further comprising annealing the first base region.

33. The method of claim 29, wherein forming the first emitter region below the trench includes implanting the first emitter region via a bottom portion of the trench.

34. The method of claim 29, wherein forming the first emitter region below the trench includes out diffusing the first emitter region from the conductive material.

35. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming a conductive material includes shorting the conductive material to a conductor in the semiconductor device in a manner that maintains the conductive material at a voltage level of the conductor, and wherein shorting the conductive material to a conductor includes shorting the conductive material to a conductor that is adapted to hold the conductive material at a voltage level that reduces stress on dielectric material adjacent to the conductive material.

36. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming a conductive material includes shorting the conductive material to a conductor in the semiconductor device in a manner that maintains the conductive material at a voltage level of the conductor, and wherein shorting the conductive material includes shorting the conductive material to a portion of a thyristor that includes the thyristor body region in the substrate.

37. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming a conductive material includes shorting the conductive material to a conductor in the semiconductor device in a manner that maintains the conductive material at a voltage level of the conductor, and wherein shorting the conductive material includes shorting the conductive material to a well region adjacent to the trench.

38. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein forming the insulative liner, forming the conductive material and forming the conductive thyristor control port includes configuring and arranging the insulative liner, the conductive material and the conductive thyristor control port so that the conductive thyristor control port controls current in the thyristor and the conductive material does not control current in the thyristor.

39. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein providing a trench in the substrate includes providing a trench between the thyristor region and a sinker region adapted to make electrical contact to an emitter region of the thyristor, wherein forming the insulative liner includes forming an insulative liner that is adapted to electrically insulate the conductive material from the sinker region.

40. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate; and

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling to the thyristor body for changing the potential across a majority of a cross-section of the at least one thyristor body region in the substrate independently from any MOS inversion channel formation against the at least one thyristor body region in the substrate and for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body.

41. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body;

masking a first portion of the conductive material and etching a second portion of the conductive material laterally between the first portion and said at least one region in the substrate such that a the first portion and a lower portion of the second portion remain unetched;

forming a second insulative liner on the first portion and on the lower portion where the second portion of the conductive material has been etched; and

wherein forming a conductive thyristor control port includes forming a portion of the conductive thyristor control port over the lower portion of the conductive material, wherein the insulative liners are adapted to electrically insulate the conductive material from the said at least one region and the second control port.

42. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein the substrate includes a well region buried therein;

forming a buried emitter region in the well region; and

forming a conductive contact extending to the well region, the conductive contact being configured and arranged for being held at a selected voltage state.

43. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body, wherein the substrate includes a well region buried therein,

forming a buried emitter region in the well region; and

forming a conductive contact extending to the well region, the conductive contact being configured and arranged for reducing the lifetime of carriers in the buried emitter region during a state changing operation of the thyristor body.

44. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body; and

removing a portion of the insulative liner at a bottom portion of the trench, wherein forming a conductive material includes forming conductive material on a bottom portion of the trench where the insulative liner material has been removed.

45. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body; and

out-diffusing the conductive material via the bottom portion of the trench where in insulative liner material has been removed.

46. A method for manufacturing a semiconductor device having a substrate and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

forming a conductive thyristor control port in the trench that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body;

wherein providing a trench in the substrate laterally adjacent to said at least one region in the substrate includes forming a nitride etch stop on an upper surface of the substrate and using the nitride etch stop to prevent the substrate from being etched while etching the trench; and

forming a sidewall spacer on sidewalls of the etched trench; and

implanting a portion of the substrate below the trench while using the sidewall spacer to prevent portions of the substrate adjacent to the sidewalls of the trench from being implanted.

47. A method for manufacturing a thyristor-based semiconductor device having a substrate and a thyristor, the method comprising:

forming a nitride etch stop on the substrate and etching a trench having sidewalls in the substrate and laterally adjacent to a dopable portion of the substrate;

blanket implanting the substrate and forming a well region and a first base region of the thyristor;

implanting a portion of the substrate below the trench and forming a first emitter region of the thyristor in the well region, the first emitter region being electrically coupled to the first base region;

growing an oxide liner on the trench sidewalls and thereby forming a lined trench;

filling a portion of the lined trench with polysilicon, the oxide liner being arranged to insulate the polysilicon filler from the dopable portion;

etching a portion of the polysilicon;

using the polysilicon to prevent etching of a portion of the oxide liner laterally adjacent to the polysilicon, etching a portion of the oxide liner over the polysilicon;

forming a gate dielectric material on a sidewall of the trench and facing the dopable portion;

forming a gate electrode in the trench over the polysilicon and adjacent to the gate dielectric material;

doping the dopable portion to a polarity that is opposite from the polarity of the first base region and forming a second thyristor base region electrically coupled to the first base region;

forming a second emitter region of the thyristor coupled to the second base region; and

wherein the gate electrode is adapted for capacitively coupling at least one voltage transition at least one of the base regions for causing an outflow of minority carriers from the at least one of the base regions and switching the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the emitter regions.

48. A method for manufacturing a semiconductor device having a substrate with a well region and a thyristor body having opposite end regions and at least one region in the substrate, the method comprising:

providing a trench in the substrate laterally adjacent to said at least one region in the substrate;

forming an insulative liner material in the trench and thereby providing a lined trench;

forming a conductive material in a portion of the lined trench, the insulative liner material being arranged to electrically insulate the conductive material from said at least one region in the substrate;

implanting a portion of the substrate below the trench and forming a first emitter region of the thyristor within the well region; and

forming a conductive thyristor control port in the trench,separate from said conductive material that is configured and arranged for capacitively coupling at least one voltage transition to the at least one region in the substrate, wherein the at least one region in the substrate has a cross section adapted so that the capacitive coupling of at least one voltage transition from the control port switches the thyristor-based semiconductor device at least from a current-passing mode to a current-blocking mode for current flow between the opposite end regions of the thyristor body.