Semiconductor device

• US 9,478,648 B2
• Filed: 12/04/2015
• Issued: 10/25/2016
• Est. Priority Date: 01/19/2015
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Ikura, Yoshihiro
• Primary Examiner(s): Landau, Matthew
• Assistant Examiner(s): WITHERS, GRANT S
• Application Number:
  US14/959,877
• Publication Number:
  US 20160211354A1
• Time in Patent Office: 326 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 27/0823 including vertical bipolar transistors only
• 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 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/0804 Emitter regions of bipolar transistors
• CPC Class Codes: H01L 29/0821 Collector regions of bipolar transistors
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/402 Field plates
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT

Abstract

A shield electrode is formed above a floating p region in a semiconductor layer and connected to a gate electrode in a trench. The shield electrode is composed of a material having an electrical resistivity lower than that of the gate electrode.

Claims

1. A semiconductor device, comprising:

a first semiconductor layer of a first conductivity type;

a second semiconductor layer of a second conductivity type provided on one surface of the first semiconductor layer;

a third semiconductor layer of the first conductivity type selectively provided in the second semiconductor layer;

a fourth semiconductor layer of the second conductivity type selectively provided in the second semiconductor layer so as to be adjacent and connected to the third semiconductor layer;

trenches each penetrating the second semiconductor layer to reach the first semiconductor layer, dividing the second semiconductor layer into a base region and a floating region, the base region having the third and fourth semiconductor layers therein, one sidewall of each of the trenches abutting the third semiconductor layer;

a fifth semiconductor layer of the second conductivity type provided below and electrically connected to another surface of the first semiconductor layer;

an emitter electrode electrically connected to the third semiconductor layer and the fourth semiconductor layer and electrically insulated from the floating region of the second semiconductor layer;

a collector electrode electrically connected to the fifth semiconductor layer;

a gate electrode provided in each of the trenches;

a gate insulating film provided in each of the trenches between the corresponding gate electrode and the trench;

a shield electrode provided over the floating region of the second semiconductor layer, the shield electrode being made of a material having an electrical resistivity lower than that of the gate electrode and being electrically connected to the gate electrode; and

an insulating film provided between the shield electrode and the floating region of the second semiconductor layer.

2. The semiconductor device according to claim 1,

wherein the shield electrode is made of a conductive film including a single film or a multilayer film comprising one or more of a metal silicide, a metal having a high melting point, and a metallic nitride having a high melting point.

3. The semiconductor device according to claim 2,

wherein a film thickness of the shield electrode is 10 nm to 800 nm.

4. The semiconductor device according to claim 3,

wherein the shield electrode laterally extends above the trench to directly connect to the gate electrode.

5. The semiconductor device according to claim 4,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

6. The semiconductor device according to claim 3,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

7. The semiconductor device according to claim 2,

wherein the shield electrode laterally extends above the trench to directly connect to the gate electrode.

8. The semiconductor device according to claim 7,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

9. The semiconductor device according to claim 2,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

10. The semiconductor device according to claim 1,

wherein a film thickness of the shield electrode is 10 nm to 800 nm.

11. The semiconductor device according to claim 10,

wherein the shield electrode laterally extends above the trench to directly connect to the gate electrode.

12. The semiconductor device according to claim 11,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

13. The semiconductor device according to claim 10,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

14. The semiconductor device according to claim 1,

wherein the shield electrode laterally extends above the trench to directly connect to the gate electrode.

15. The semiconductor device according to claim 14,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.

16. The semiconductor device according to claim 1,

wherein the insulating film disposed between the shield electrode and the floating region has a thickness greater than that of the gate insulating film.