Semiconductor device with termination structure for power MOSFET applications

Patent metadata

Field	Value
Publication number	US-9356022-B2
Application number	US-201514807633-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Feb 25, 2013
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A semiconductor device may have an active device region containing a plurality of active devices and a termination structure that surrounds the active device region. The termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region. The active device region and termination structure are formed into a semiconductor material of a first conductivity type. The first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal.

First claim

What is claimed is:

1. A semiconductor device comprising:
an active device region containing a plurality of active devices; and

a termination structure that surrounds the active device region, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region,
wherein the active device region and termination structure are formed into a semiconductor material of a first conductivity type,
wherein the first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal; and
a termination shield formed between the first and second conductive regions, wherein the termination shield is electrically isolated from the first and second portions of conductive material, and wherein the termination shield is maintained at a source potential.

2. The semiconductor device of claim 1 , wherein the first and second conductive regions and the insulating region are formed in a common trench in the semiconductor material that surrounds the active region.

3. A semiconductor device comprising:
an active device region containing a plurality of active devices; and
a termination structure that surrounds the active device region, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region,
wherein the active device region and termination structure are formed into a semiconductor material of a first conductivity type,
wherein the first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal; and
a Schottky contact formed below the termination structure.

4. The semiconductor device of claim 3 , wherein the first and second conductive regions and the insulating region are formed in a common trench in the semiconductor material that surrounds the active region.

5. A semiconductor device comprising:
an active device region containing a plurality of active devices; and
a termination structure that surrounds the active device region, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region,
wherein the active device region and termination structure are formed into a semiconductor material of a first conductivity type,
wherein the first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal, wherein the first and second conductive regions and the insulating region are formed in a common trench that surrounds the active region, and wherein a dielectric material lining an upper portion of sidewalls of the common trench is a first thickness, and a dielectric material lining a lower portion of the sidewalls of the common trench is a second thickness, wherein the second thickness is greater than the first thickness.

6. The semiconductor device of claim 5 , further comprising:
a source layer of a second conductivity type formed in an upper portion of the semiconductor material bounded by an outermost active semiconductor device of the plurality and the termination trench; and
a body layer of the first conductivity type formed below the source layer.

7. The semiconductor device of claim 6 , wherein a distance between the outermost active semiconductor device and the termination trench is equal to a distance separating each of the active semiconductor devices from each other.

8. The semiconductor device of claim 5 , further comprising an electrical field line tuning region of the second conductivity type formed below the termination structure.

9. The semiconductor device of claim 5 , wherein the termination structure further surrounds a gate pickup feature.

10. A semiconductor device comprising:
an active device region containing a plurality of active devices; and
a termination structure that surrounds the active device region, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region, wherein the termination structure further surrounds an electrostatic discharge feature,
wherein the active device region and termination structure are formed into a semiconductor material of a first conductivity type,
wherein the first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal.

11. The semiconductor device of claim 10 , wherein the first and second conductive regions and the insulating region are formed in a common trench in the semiconductor material that surrounds the active region.

12. A semiconductor device comprising:
an active device region containing a plurality of active devices; and
a termination structure that surrounds the active device region, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region, wherein a Schottky contact is formed outside of the termination structure,
wherein the active device region and termination structure are formed into a semiconductor material of a first conductivity type,
wherein the first conductive region is electrically connected to a gate metal and the second conductive region is connected to a drain metal.

13. The termination structure of claim 12 , wherein the Schottky contact includes a body clamp feature.

14. A method for forming a semiconductor device comprising:
forming an active device region containing a plurality of active devices in a semiconductor material of a first conductivity type;
forming a termination structure that surrounds the active device region in the semiconductor material of the first conductivity type, wherein the termination structure includes a first conductive region that surrounds the active device region, an insulator region that surrounds the first conductive region, and a second conductive region that surrounds the first conductive region and the insulator region, wherein forming the termination structure includes:
forming a termination trench in the semiconductor material of the first conductivity type, wherein the termination trench surrounds the active device region;
lining sidewalls and a bottom surface of the termination trench with a dielectric material;
disposing a conductive material in the termination trench, wherein the disposed conductive material lines the dielectric material on the sidewalls and the bottom surface;
removing the conductive material on the bottom surface of the termination trench, wherein the first conductive region includes a first portion of the conductive material that remains on a sidewall of the termination trench that is closest to the one or more active semiconductor devices, and wherein second conductive region includes a second portion of the conductive material remains on a sidewall of the termination trench furthest from the one

Assignees

• Alpha & Omega Semiconductor

Inventors

• Lee Yeeheng
• Bobde Madhur
• Calafut Daniel
• Yilmaz Hamza
• Wang Xiaobin
• Pan Ji
• Chang Hong
• Kim Jongoh

Classifications

• H10P50/691

  for Group V materials or Group III-V materials · CPC title

• H10P30/20

  into semiconductor materials, e.g. for doping · CPC title

• H10D64/516

  the thicknesses being non-uniform · CPC title

• H10D64/256

  for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies (source or drain electrodes of TFTs H10D30/673) · CPC title

• H10D62/107

  Buried supplementary regions, e.g. buried guard rings  (multi-RESURF H10D62/111) · CPC title