MOSGATED POWER SEMICONDUCTOR DEVICE WITH SOURCE FIELD ELECTRODE

• US 20090096019A1
• Filed: 10/01/2008
• Published: 04/16/2009
• Est. Priority Date: 02/08/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Girdhar, Dev Alok, Henson, Timothy Donald
• Granted Patent: US 8,884,367 B2
• Time in Patent Office: Days
• US Class Current: 257/331
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• 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 29/76 Unipolar devices , e.g. field effect transistors
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A power semiconductor device which includes a source field electrode, and at least one insulated gate electrode adjacent a respective side of the source field electrode, the source field electrode and the gate electrode being disposed in a common trench.

Claims

1. A power semiconductor device comprising:

a semiconductor body having a common conduction region of one conductivity type, and a base region of another conductivity type, said semiconductor body including a first surface;

a trench extending from said first surface through said base region and into said common conduction region, said trench including at least two opposing sidewalls and a bottom;

an insulated gate electrode including a gate insulation adjacent one of said sidewalls and a gate electrode adjacent said gate insulation and spanning said base region;

a source field electrode inside said trench, said source field electrode including a first portion spanning said gate electrode and a second portion extending to a depth below said insulated gate electrode;

a source region adjacent a sidewall of said trench and said base region; and

a source contact ohmically coupled to said source region, and at least a portion of said source field electrode that faces a direction parallel to said semiconductor body.

2. A semiconductor device according to claim 1, wherein said source contact is ohmically coupled to a portion of a top surface of said source field electrode.

3. A semiconductor device according to claim 1, further comprising a bottom insulation body disposed between said second portion of said source field electrode and said sidewalls and said bottom of said trench.

4. A semiconductor device according to claim 3, wherein said bottom insulation body is thicker than said gate insulation.

5. A semiconductor device according to claim 3, wherein said bottom insulation body includes a first portion disposed below said gate electrode and a second portion opposite said first portion having a recess formed therein and another electrode formed in said recess ohmically coupled to said source contact.

6. A semiconductor device according to claim 1, wherein said source field electrode is comprised of conductive polysilicon.

7. A semiconductor device according to claim 1, wherein said gate electrode is comprised of conductive polysilicon.

8. A semiconductor device according to claim 1, wherein said semiconductor body is comprised of epitaxial silicon.

9. A semiconductor device according to claim 8, wherein said epitaxial silicon is formed over a silicon substrate, and further comprising a drain contact ohmically connected to said silicon substrate.