Edge termination for semiconductor devices

• US 7,911,021 B2
• Filed: 04/06/2009
• Issued: 03/22/2011
• Est. Priority Date: 06/02/2008
• Status: Active Grant

• Current Assignee: MaxPower Semiconductor, Inc. (Vishay Intertechnology Incorporated)
• Original Assignee: MaxPower Semiconductor, Inc. (Vishay Intertechnology Incorporated)
• Inventors: Zeng, Jun, Paul, Amit, Darwish, Mohamed N.
• Primary Examiner(s): Dickey; Thomas L
• Assistant Examiner(s): YUSHIN, NIKOLAY K
• Application Number:
  US12/418,808
• Publication Number:
  US 20090294892A1
• Time in Patent Office: 715 Days
• Field of Search: 257/494, 257/141, 257/E29.327, 257/E29.008, 257/487, 257/491, 257/534, 257/E29.007, 438/170, 438/142, 438/248
• US Class Current: 257/494
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/0692 Surface layout
• CPC Class Codes: H01L 29/408 with an insulating layer with a particular dielectric or electrostatic property, e.g. with static charges or for controlling trapped charges or moving ions, or with a plate acting on the insulator potential or the insulator charges, e.g. for controlling charges effect or potential distribution in the insulating layer, or with a semi-insulating layer contacting directly the semiconductor surface
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/8611 Planar PN junction diodes

Abstract

A high-voltage termination structure includes a peripheral voltage-spreading network. One or more trench structures are connected at least partly in series between first and second power supply voltages. The trench structures include first and second current-limiting structures connected in series with a semiconductor material, and also includes permanent charge in a trench-wall dielectric. The current-limiting structures in the trench structures are jointly connected in a series-parallel ladder configuration. The current-limiting structures, in combination with the semiconductor material, provide a voltage distribution between the core portion and the edge portion.

Claims

1. A high-voltage termination structure, comprising:

a peripheral voltage-spreading network, comprising one or more trench structures connected at least partly in series between first and second voltages;

said trench structures respectively comprising current-limiting structures which are connected in series with a semiconductor material, and which include intentionally introduced net permanent charge in a trench-wall dielectric,

wherein said current-limiting structures, in combination with said semiconductor material, provide a voltage distribution of the difference between said first and second voltages.

2. The structure of claim 1, wherein said first and second voltages are power supply voltages.

3. The structure of claim 1, wherein said semiconductor material is silicon.

4. The structure of claim 1, wherein at least one said current-limiting structure comprises a junction diode.

5. The structure of claim 1, wherein said peripheral voltage-spreading network completely surrounds a core portion which includes active semiconductor devices.

6. The structure of claim 1, wherein said permanent charge in said sidewalls is sufficient to cause inversion of at least one adjacent portion of semiconductor material.

7. The structure of claim 1, wherein said trench structures respectively comprise first and second current-limiting structures connected in series with a semiconductor material, wherein the first and second current-limiting structures comprise diodes.

8. The structure of claim 7, wherein said semiconductor material is silicon.

9. A high-voltage device termination structure, comprising:

a patterned combination of at least one first structure which conducts lateral current with one or more second structures which do not conduct lateral current;

said first structure being laterally confined, by said second structures, to define a continuous path from a core portion to an edge portion, which is more than three times as long as the direct distance from said core portion to said edge portion;

whereby the conductivity of said first structure defines a voltage distribution between said core portion and said edge portion.

10. The device of claim 9, further comprising permanent charge positioned within said second structure, wherein said permanent charge induces leakage paths primarily along structure edges.

11. The device of claim 9, wherein said edge portion is a device edge.

12. The device of claim 9, wherein said core portion comprises at least one effective device.

13. The device of claim 9, wherein said second structures include a plurality of trenches containing a solid dielectric.

14. The device of claim 9, wherein said second structures include a plurality of dielectric trenches, and at least one of said dielectric trenches is wider than the other dielectric trenches.

15. A semiconductor device, comprising:

a core portion which controls passage of current between at least two terminals;

and an edge portion which includes a peripheral voltage-spreading network, comprising one or more trench structures connected at least partly in series between first and second terminals;

said trench structures respectively comprising current-limiting structures which are connected in series with a semiconductor material, and which include intentionally introduced permanent net charge in a trench-wall dielectric,

wherein said current-limiting structures, in combination with said semiconductor material, provide a voltage distribution between said core portion and said edge portion.

16. The device of claim 15, wherein said core portion includes permanent charge, at one or more interfaces.

17. The device of claim 15, wherein said edge portion is a device edge.

18. The device of claim 15, wherein said core portion comprises at least one effective device.

19. The device of claim 15, wherein said second structures include a plurality of dielectric trenches, and at least one of said dielectric trenches is wider than the other dielectric trenches.