Method of manufacturing a silicon carbide semiconductor device by removing amorphized portions

Patent metadata

Field	Value
Publication number	US-10217636-B2
Application number	US-201815919918-A
Country	US
Kind code	B2
Filing date	Mar 13, 2018
Priority date	Oct 9, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A trench is formed that extends from a main surface into a crystalline silicon carbide semiconductor layer. A mask is formed that includes a mask opening exposing the trench and a rim section of the main surface around the trench. By irradiation with a particle beam a first portion of the semiconductor layer exposed by the mask opening and a second portion outside of the vertical projection of the mask opening and directly adjoining to the first portion are amorphized. A vertical extension of the amorphized second portion gradually decreases with increasing distance to the first portion. The amorphized first and second portions are removed.

First claim

What is claimed is:

1. A semiconductor device comprising:
a trench gate structure extending from a first surface into a semiconductor body,
wherein the trench gate structure fills a trench,
wherein the trench being rounded and/or chamfered along a rim section of the first surface, and
wherein, in a horizontal cross-section parallel to the first surface, the trench gate structure includes a long side, a short side and a rounded transition between the short side and the long side.

2. The semiconductor device of claim 1 , wherein the long side is a straight long side and the short side is a straight short side.

3. The semiconductor device of claim 1 , wherein the semiconductor body is of crystalline silicon carbide.

4. The semiconductor device of claim 1 , further comprising source zones in the semiconductor body, which source zones directly adjoin the trench gate structure on opposing sides of the trench.

5. The semiconductor device of claim 1 , further comprising source zones in the semiconductor body, which source zones directly adjoin the trench gate structure on only one side.

6. A semiconductor device, comprising:
a trench extending from a first surface of a semiconductor body into the semiconductor body, the semiconductor body comprising crystalline silicon carbide,
wherein the trench has a chamfered and/or substantially rounded rim with a tilted surface section and a tapering surface section,
wherein the tilted surface section and the first surface enclose a first angle and the tilted surface section and the tapering surface section enclose a second angle, the first angle being different from the second angle, and
wherein, in a horizontal cross-section parallel to the first surface, the trench includes a long side, a short side and a rounded transition between the short side and the long side.

7. The semiconductor device of claim 6 , wherein the first angle is larger than the second angle.

8. The semiconductor device of claim 6 , wherein the tapering surface section and a side wall of the trench enclose a third angle, the third angle being larger than the second angle.

9. The semiconductor device of claim 6 , wherein the tapering surface section and a side wall of the trench enclose a third angle, the first angle and the third angle being substantially equal.

10. The semiconductor device of claim 6 , wherein the trench has rounded surface sections along corners of a bottom of the trench.

11. The semiconductor device of claim 6 , wherein the trench comprises a trench gate structure.

12. A method of forming a semiconductor device, the method comprising:
forming a trench extending from a first surface of a semiconductor body into the semiconductor body, the semiconductor body comprising crystalline silicon carbide,
wherein the trench has a chamfered and/or substantially rounded rim with a tilted surface section and a tapering surface section,
wherein the tilted surface section and the first surface enclose a first angle and the tilted surface section and the tapering surface section enclose a second angle, the first angle being different from the second angle, and
wherein, in a horizontal cross-section parallel to the first surface, the trench includes a long side, a short side and a rounded transition between the short side and the long side.

13. The method of claim 12 , wherein the first angle is larger than the second angle.

14. The method of claim 12 , wherein the tapering surface section and a side wall of the trench enclose a third angle, the third angle being larger than the second angle.

15. The method of claim 12 , wherein the tapering surface section and a side wall of the trench enclose a third angle, the first angle and the third angle being substantially equal.

16. The method of claim 12 , wherein the trench has rounded surface sections along corners of a bottom of the trench.

17. The method of claim 12 , wherein forming the trench comprises forming a trench gate structure.

Assignees

• Infineon Technologies Ag

Inventors

• Aichinger Thomas
• Poenariu Victorina
• Bergner Wolfgang
• Esteve Romain
• Kueck Daniel
• Peters Dethard
• Reinwald Gerald
• Rupp Roland
• Unegg Gerald

Classifications

• H10P50/242

  of Group IV materials · CPC title

• H10D64/01366

  the semiconductor being silicon carbide · CPC title

• H10P50/00 Primary

  Etching of wafers, substrates or parts of devices · CPC title

• H01L29/401

  Electricity · mapped topic

• H01L21/049

  Electricity · mapped topic