High power semiconductor device

• US 10,121,886 B2
• Filed: 07/31/2017
• Issued: 11/06/2018
• Est. Priority Date: 08/01/2016
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Chen, Ming-Chin, Lin, Yi-Chih, Tu, Shang-Ju
• Primary Examiner(s): Yushin, Nikolay
• Application Number:
  US15/664,879
• Publication Number:
  US 20180033880A1
• Time in Patent Office: 463 Days
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 29/0611 for increasing or controlling the breakdown voltage of reverse biased devices H01L29/0661 takes precedence
• CPC Class Codes: H01L 29/0847 of field-effect transistors with insulated gate H01L29/0653 takes precedence; with a passive supplementary region between source or drain and substrate related to punch-through, capacity or isolation phenomena H01L29/1079; with LDD or DDD structure H01L29/7833; for thin film transistors H01L29/78618
• CPC Class Codes: H01L 29/0891 of field-effect transistors with Schottky gate
• CPC Class Codes: H01L 29/1054 with a variation of the composition, e.g. channel with strained layer for increasing the mobility
• CPC Class Codes: H01L 29/1066 Gate region of field-effect devices with PN junction gate
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/205 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• CPC Class Codes: H01L 29/42316 for field-effect transistors
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 29/7787 with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET
• CPC Class Codes: H01L 29/868 PIN diodes

Abstract

This application provides a high power semiconductor device, which is characterized by forming two diodes connected in parallel and a schottky contact on a channel layer to lower the turn-on voltage and turn-on resistance of the high power semiconductor device at the same time and to enhance the breakdown voltage.

Claims

1. A high power semiconductor device comprising:

a substrate;

a channel layer formed on the substrate and comprising a first region, a second region, and a third region;

a first barrier layer formed on the first region of the channel layer;

a first cap layer having a first conductivity type and formed on the first barrier layer;

a first electrode formed on the first barrier layer;

a second electrode formed on the first cap layer;

a second barrier layer formed on the second region of the channel layer;

a second cap layer having the first conductivity type and formed on the second barrier layer;

a third electrode formed on the second barrier layer;

a fourth electrode formed on the second cap layer;

a trench comprising a bottom wall and being disposed between the first barrier layer and the second barrier layer, wherein the trench exposes the third region of the channel layer; and

a connecting portion covering the bottom wall of the trench, electrically connected with the second electrode and the fourth electrode, and forming a schottky contact with the third region of the channel layer.

2. The high power semiconductor device as claimed in claim 1, wherein the first electrode and a portion of the third electrode are formed on the channel layer.

3. The high power semiconductor device as claimed in claim 1, further comprising a buffer layer disposed between the substrate and the channel layer, and a dielectric layer formed among the connecting portion, the bottom wall, the first cap layer, and the second cap layer.

4. The high power semiconductor device as claimed in claim 3, wherein a material of the dielectric layer comprises silicon nitride, silicon oxide, or silicon oxynitride.

5. The high power semiconductor device as claimed in claim 1, further comprising:

a first ohmic contact layer formed on the first cap layer; and

a second ohmic contact layer formed on the second cap layer, wherein the second electrode is formed on the first ohmic contact layer, and the fourth electrode is formed on the second ohmic contact layer.

6. The high power semiconductor device as claimed in claim 5, wherein the first cap layer comprises a first edge away from the trench, the first ohmic contact layer comprises a second edge away from the trench, the second layer comprises a third edge away from the trench, the second ohmic contact layer comprise a fourth edge away from the trench, the first edge is aligned with the second edge, and/or the third edge is aligned with the fourth edge.

7. The high power semiconductor device as claimed in claim 6, comprising a third cap layer having a first conductivity type and next to the first edge of the first cap layer, and a fourth cap layer having the first conductivity type and next to the third edge of the second cap layer.

8. The high power semiconductor device as claimed in claim 7, wherein a thickness of the third cap layer is equal to or smaller than a thickness of the first cap layer, and a thickness of the fourth cap layer is equal to or smaller than a thickness of the second cap layer.

9. The high power semiconductor device as claimed in claim 7, wherein a thickness of the third cap layer and a thickness of the fourth cap layer are smaller than 30 Å

.

10. A high power semiconductor device comprising:

a substrate;

a first PIN diode structure disposed on the substrate;

a second PIN diode structure disposed on the substrate; and

a schottky-interface structure disposed on the substrate and between the first PIN diode structure and the second PIN diode structure, wherein the first PIN diode structure, the second PIN diode structure, and the schottky-interface structure are electrically connected with one another in parallel.

11. A high power semiconductor device comprising:

a substrate;

a channel layer disposed on the substrate;

a first semiconductor gate structure disposed on the channel layer;

a metal-insulator-semiconductor gate structure disposed on the channel layer and having a recess; and

a second semiconductor gate structure disposed on the channel layer;

wherein the first semiconductor gate structure, the metal-insulator-semiconductor gate structure, and the second semiconductor gate structure are electrically connected with one another in parallel.

12. The high power semiconductor as claimed in claim 11, wherein the first semiconductor gate structure comprises a first electrode, the metal-insulator-semiconductor gate structure comprises a first connecting portion, the second semiconductor gate structure comprises a second electrode, and the connecting portion is electrically connected to the first electrode and the second electrode.