VARIABLE THRESHOLD TRENCH IGBT WITH OFFSET EMITTER CONTACTS

• US 20090146177A1
• Filed: 10/16/2008
• Published: 06/11/2009
• Est. Priority Date: 10/17/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Ng, Chiu, Chao, Yuan-Heng
• Granted Patent: US 8,067,797 B2
• Time in Patent Office: Days
• US Class Current: 257/139
• CPC Class Codes: H01L 29/0839 Cathode regions of thyristors
• 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 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT

Abstract

A trench type IGBT as disclosed herein includes a plurality of channel regions having one threshold voltage for the normal operation of the device and a plurality of channel regions having a threshold voltage higher than the threshold voltage for the normal operation of the device.

Claims

1. An IGBT comprising:

a semiconductor body that includes a top surface and a bottom surface, and a drift region of one conductivity type;

a base region of another conductivity type over said drift region;

a plurality of trenches extending through said base region into said drift region, emitter regions adjacent said trenches; and

an insulated gate electrode inside each of said trenches, wherein each trench includes a channel region adjacent a respective sidewall thereof which upon application of a respective threshold voltage can be converted to a channel connecting an adjacently disposed emitter region and said drift region, and wherein at least a first group of said channel regions requires a first threshold voltage and at least a second group of said channel regions requires a second threshold voltage, said first threshold voltage is a device threshold voltage and said first threshold voltage and said second threshold voltage are different from one another.

2. The IGBT of claim 1, wherein said second threshold voltage is greater than said first threshold voltage.

3. The IGBT of claim 1, wherein at least one of said trenches includes a channel region from said first group of said channels adjacent one sidewall thereof and a channel region from said second group of said channels adjacent another sidewall thereof.

4. The IGBT of claim 1, wherein at least one of said trenches includes a channel region from said second group of said channels adjacent one sidewall thereof and a channel region from said second group of said channels adjacent another sidewall thereof.

5. The IGBT of claim 1, wherein at least one of said trenches includes a channel region from said first group of said channels adjacent one sidewall thereof and a channel region from said second group of said channels adjacent another sidewall thereof and at least another one of said trenches includes a channel region from said second group of said channels adjacent one sidewall thereof and a channel region from said second group of said channels adjacent another sidewall thereof.

6. The IGBT of claim 1, further comprising a contact region of said another conductivity type and lower resistivity than said base region disposed between and asymmetrically positioned between at least two of said trenches, said contact region having a channel region of the first group of said channel region adjacent one side thereof, and a channel region from the second group of said channel region adjacent another side thereof.

7. The IGBT of claim 1, further comprising a contact region of said another conductivity type and lower resistivity than said base region positioned between at least two of said trenches, said contact region having a channel region of said second group of said channel region adjacent one side thereof, and a channel region from said second group of said channel region adjacent another side thereof.