IP Library › Granted Patent US 10,211,333
Granted Patent B2
US 10,211,333 · App. 15/498,366 · Granted Feb 19, 2019

Scalable SGT structure with improved FOM

Inventors: Madhur Bobde (Sunnyvale, CA); Sik Lui (Sunnyvale, CA)
Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
H01L29/7813H01L21/28273H01L29/407H01L29/4236H01L29/42324H01L29/42376H01L29/66734H01L29/66825H01L29/7889
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 10,211,333
App. No.
15/498,366
Granted
Feb 19, 2019
Kind
B2
Abstract

A shielded gate trench field effect transistor comprises an epitaxial layer above a substrate, a body region, a trench formed in the body region and epitaxial layer and one or more source regions formed in a top surface of the body region and adjacent a sidewall of the trench. A shield electrode is formed in a lower portion of the trench and a gate electrode is formed in an upper portion of the trench above the shield electrode. The shield electrode is insulated from the epitaxial layer by a first dielectric layer. The gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer. The first and second dielectric layer has a same thickness.

Claims (59)

1. A shielded gate trench field effect transistor, comprising:

a) a substrate of a first conductivity type;

b) an epitaxial layer of the first conductivity type provided on top of the substrate;

c) a body region of a second conductivity type that is opposite to the first conductivity type formed above the epitaxial layer;

d) a trench formed in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer and wherein the trench has a pitch less than 1 μm;

e) a shield electrode formed in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

f) a gate electrode formed in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness; and

g) one or more source regions of the first conductivity type formed in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench.

2. The field effect transistor of claim 1 , wherein the trench has a pitch about 0.6 um.

3. A shielded gate trench field effect transistor, comprising:

a) a substrate of a first conductivity type;

b) an epitaxial layer of the first conductivity type provided on top of the substrate;

c) a body region of a second conductivity type that is opposite to the first conductivity type formed above the epitaxial layer;

d) a trench formed in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer;

e) a shield electrode formed in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

f) a gate electrode formed in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness ranging between 10 to 25 nm; and

g) one or more source regions of the first conductivity type formed in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench.

4. A shielded gate trench field effect transistor, comprising:

a) a substrate of a first conductivity type;

b) an epitaxial layer of the first conductivity type provided on top of the substrate;

c) a body region of a second conductivity type that is opposite to the first conductivity type formed above the epitaxial layer;

d) a trench formed in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer and wherein the trench is extended in depth about 0.5 microns or less;

e) a shield electrode formed in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

f) a gate electrode formed in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness; and

g) one or more source regions of the first conductivity type formed in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench.

5. The field effect transistor of claim 1 , wherein the epitaxial layer has a dopant concentration that is constant throughout its depth.

6. The field effect transistor of claim 1 , wherein the shield electrode is as wide as the gate electrode.

7. A shielded gate trench field effect transistor, comprising:

a) a substrate of a first conductivity type;

b) an epitaxial layer of the first conductivity type provided on top of the substrate;

c) a body region of a second conductivity type that is opposite to the first conductivity type formed above the epitaxial layer;

d) a trench formed in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer;

e) a shield electrode formed in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

f) a gate electrode formed in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness; and

g) one or more source regions of the first conductivity type formed in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench, wherein the shield electrode is an upside down T-shaped electrode with a horizontal portion and a vertical portion, and the gate electrode is split into two portions, each provided above the horizontal portion of the shield electrode.

8. The field effect transistor of claim 1 , further comprising a P column formed in a core cell connected to the body region at the surface or orthogonal to the core cell.

9. The field effect transistor of claim 1 , further comprising a source pad formed above the body region, wherein the source pad is electrically connected to the one or more source regions and insulated from the gate electrode and the shield electrode, the source pad providing an external contact to the one or more source region.

10. A shielded gate trench field effect transistor, comprising:

a) a substrate of a first conductivity type, wherein a drain pad is provided under the substrate;

b) an epitaxial layer of the first conductivity type provided on top of the substrate;

c) a body region of a second conductivity type that is opposite to the first conductivity type formed above the epitaxial layer;

d) a trench formed in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer;

e) a shield electrode formed in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

f) a gate electrode formed in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness; and

g) one or more source regions of the first conductivity type formed in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench.

11. A method for manufacturing a shielded gate trench field effect transistor, comprising:

a) providing an epitaxial layer of a first conductivity type on top of a substrate of the first conductivity type;

b) providing a body region of a second conductivity type above the epitaxial layer, wherein the second conductivity type is opposite to the first conductivity type;

c) providing a trench in the body region and epitaxial layer, wherein the trench is lined with a first dielectric layer and the trench has a pitch less than 1 μm;

d) providing a shield electrode in a lower portion of the trench, wherein the shield electrode is insulated from the epitaxial layer by the first dielectric layer;

e) providing a gate electrode in an upper portion of the trench above the shield electrode, wherein the gate electrode is insulated from the epitaxial layer by the first dielectric layer and insulated from the shield electrode by a second dielectric layer, wherein the first and second dielectric layers have the same thickness; and

f) providing one or more source regions of the first conductivity type in a top surface of the body region, wherein each source region is adjacent a sidewall of the trench.

12. The method of claim 11 , wherein the trench has a pitch about 0.6 um.

13. The method of claim 11 , wherein the thickness of the first and second dielectric layer is in a range between 10 to 25 nm.

14. The method of claim 11 , wherein the trench is extended in depth about 0.5 microns or less.

15. The method of claim 11 , wherein the epitaxial layer has a dopant concentration that is constant throughout its depth.

16. The method of claim 11 , wherein the shield electrode is as wide as the gate electrode.

17. The method of claim 11 , wherein the shield electrode is an upside down T-shaped electrode with a horizontal portion and a vertical portion, and the gate electrode is split into two portions, each provided above the horizontal portion of the shield electrode.

18. The method of claim 11 , further comprising forming a P column formed in a core cell connected to the body region at the surface or orthogonal to the core cell.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 18, 2017
From: BOBDE, MADHUR; LUI, SIK
To: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
Reel/Frame 043033/0048 →
Continuity (1)
Related Publication 20180315846A1 · Nov 1, 2018