Vertical semiconductor component having a drift zone having a field electrode, and method for fabricating such a drift zone

• US 20050082591A1
• Filed: 08/27/2004
• Published: 04/21/2005
• Est. Priority Date: 08/27/2003
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hirler, Franz, Pfirsch, Frank, Zundel, Markus, Tihanyi, Jenoe, Henninger, Ralf
• Granted Patent: US 7,173,306 B2
• Time in Patent Office: Days
• US Class Current: 257/302
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/402 Field plates
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/861 Diodes

Abstract

The invention relates to a method for fabricating a drift zone of a vertical semiconductor component and to a vertical semiconductor component having the following features:

• • a semiconductor body (100) having a first side (101) and a second side (102),
  • a drift zone (30) of a first conduction type which is arranged in the region between the first and the second sides (101, 102) and is formed for the purpose of taking up a reverse voltage,
  • a field electrode arrangement arranged in the drift zone (30) and having at least one electrically conducted field electrode (40; 40A-40E; 90A-90J) arranged in a manner insulated from the semiconductor body (100), an electrical potential of the at least one field electrode (40; 40A-40E; 90A-90J) varying in the vertical direction of the semiconductor body (100) at least when a reverse voltage is applied.

Claims

1-21. -21. (canceled)

22. A vertical semiconductor component comprising:

a semiconductor body including a first side and a second side;

a drift zone of a first conduction type positioned in the semiconductor body between the first side and the second side, the drift zone operable to taking up a reverse voltage;

a field electrode arrangement positioned in the drift zone, the field electrode arrangement including at least one electrically conductive field electrode insulated from the semiconductor body; and

at least one semiconductor zone arranged in floating fashion in the drift zone or arranged adjoining the drift zone, wherein the at least one field electrode is electrically coupled to the at least one semiconductor zone.

23. The semiconductor component of claim 22 wherein the at least one semiconductor zone is of a second conduction type.

24. The semiconductor component of claim 22 wherein the at least one semiconductor zone is of the first conduction type and the at least one semiconductor zone is doped more heavily than the drift zone.

25. The semiconductor component of claim 22 wherein the at least one field electrode is formed such that it tapers in the vertical direction of the semiconductor body.

26. The semiconductor component of claim 22 wherein the at least one field electrode comprises a plurality of field electrodes and the at least one semiconductor zone comprises a plurality of floating semiconductor zones, with each of the plurality of field electrodes assigned to one of the semiconductor zones, and each of the plurality of semiconductor zones arranged in the vertical direction above or beside the field electrode assigned to it.

27. The semiconductor component of claim 23 wherein the at least one field electrode is surrounded by an insulation layer that has a respective cutout through which the at least one semiconductor zone of the second conduction type extends as far as the at least one field electrode.

28. The semiconductor component of claim 22 in which the at least one field electrode comprises a heavily doped semiconductor material or a metal.

29. The semiconductor component of claim 28 wherein the at least one field electrode is of the same conduction type as the at least one semiconductor zone.

30. The semiconductor component of claim 23 wherein the semiconductor component is a diode having a pn junction, the diode comprising:

a first terminal zone of the first conduction type, the first terminal zone doped more heavily than the drift zone and the first terminal zone adjoining the drift zone in the region of the first side; and

a second terminal zone of the second conduction type, the second terminal zone adjoining the drift zone in the region of the second side.

31. The semiconductor component of claim 22 wherein the semiconductor component is a Schottky diode, the diode comprising:

a terminal electrode that adjoins the drift zone on the first side and forms a Schottky contact with the drift zone.

32. The semiconductor component of claim 22 wherein the semiconductor component is formed as a transistor, the transistor comprising:

a first terminal zone of the first conduction type, the first terminal zone doped more heavily than the drift zone and the first terminal zone adjoining the drift zone in the region of the first side of the semiconductor body,

a second terminal zone of the first conduction type in the region of the second side of the semiconductor body;

a body zone of the second conduction type arranged between the second terminal zone and the drift zone; and

a control electrode insulated from the semiconductor body, the control electrode operable, upon application of a drive potential, to form a conductive channel in the body zone between the second terminal and the drift zone.

33. The semiconductor component of claim 32 wherein the body zone is coupled to one of the field electrodes arranged in a manner lying one above the other in the vertical direction.

34. The semiconductor component of claim 32 wherein the control electrode is formed in a trench extending into the semiconductor body proceeding from the second side.

35. The semiconductor component of claim 34 wherein the at least one field electrode is arranged below the control electrode in the trench.

36. The semiconductor component of claim 32 wherein the control electrode is formed above the second side of the semiconductor body.

37. The semiconductor component of claim 36 wherein the at least one field electrode is formed in a trench extending into the semiconductor body in the vertical direction.

38. A method for fabricating an electrically conductive field electrode in a vertical semiconductor component, the electrically conductive field electrode being insulated from a drift zone of a first conduction type and coupled to a semiconductor zone of a second conduction type, wherein the semiconductor zone is arranged in floating fashion, the method comprising the steps of:

providing a first semiconductor layer of the first conduction type, the first semiconductor layer including a surface;

fabricating a trench including sidewalls and a bottom in the first semiconductor layer proceeding from the surface;

applying an electrical insulation layer to the sidewalls and the bottom of the trench;

introducing an electrically conductive material into the trench to form the field electrode;

depositing a second semiconductor layer of the first conduction type onto the first semiconductor layer with the trench, and

producing a semiconductor zone of the first or second conduction type, the semiconductor zone arranged in floating fashion in the second semiconductor layer above the trench, and the semiconductor zone making contact with the field electrode.

39. The method of claim 38 wherein the electrically conductive material is a semiconductor material doped with dopants of the second conduction type and wherein the semiconductor zone is fabricated by outdiffiusion of dopant atoms of the first or second conduction type into the second semiconductor layer.

40. The method of claim 38 wherein the electrically conductive material is a metallic material, and wherein the semiconductor zone arranged in floating fashion is effected by introduction of charge carriers of the first or second conduction type via the surface of the second semiconductor layer.

41. The method of claim 40 wherein the second semiconductor layer is deposited in two stages in two partial layers, and wherein dopant atoms of the second conduction type are introduced into the semiconductor layer that is deposited first.

42. The method of claim 38 wherein, prior to the deposition of the second semiconductor layer, an insulation layer with a cutout is applied to the electrically conductive material in the trench.