Trench power device

Abstract

A trench power device includes a substrate, an epitaxial layer, a trench gate structure, a drain layer, and a source region. The trenched epitaxial layer is formed on a first surface of the substrate. The trench gate structure is located within the trench of the epitaxial layer. The drain layer is located on a second surface of the substrate. The source region is formed within the epitaxial layer on both sides of the trench gate structure. The trench gate structure includes a gate, a gate oxide layer, and a bottom dielectric layer formed within the trench. The gate oxide layer is formed on the sidewalls of the gate. The bottom dielectric layer is formed between the gate and the bottom surface of the trench. The thickness of the bottom dielectric layer is greater than the thickness of the gate oxide layer, and the top of the bottom dielectric layer includes a convex curved surface.

Claims

1. A trench-type power element, comprising: A substrate having a first surface and a second surface opposite to each other; An epitaxial layer is formed on the first surface of the substrate and has trenches; A trench gate structure is formed in the trench of the epitaxial layer; a drain layer is formed on the second surface of the substrate; The trench gate structure includes a source region formed within the epitaxial layer on both sides of the trench gate structure. The trench gate structure comprises: a gate formed within the trench; a gate oxide layer formed between the gate and the sidewall of the trench; and a bottom dielectric layer formed between the gate and the bottom surface of the trench, wherein the thickness of the bottom dielectric layer is greater than the thickness of the gate oxide layer, and the top of the bottom dielectric layer includes a convex curved surface, wherein the top of the bottom dielectric layer is a ridge bar, and the cross-section of the ridge bar has a triangular profile.

2. The trench power element as claimed in claim 1, wherein the bottom dielectric layer further includes a necking portion located between the ridge and the bottom surface of the trench.

3. The trench power device as claimed in claim 1, wherein the material of the bottom dielectric layer includes silicon oxide, silicon nitride, or metal oxide.

4. The trench power device as claimed in claim 1, wherein the substrate material includes Si, SiC, GaN, or GaAs.

5. The trench power device as claimed in claim 1, wherein the substrate comprises a glass substrate or a sapphire substrate.

6. A trench-type power element, comprising: A substrate having a first surface and a second surface opposite to each other; An epitaxial layer is formed on the first surface of the substrate and has trenches; A trench gate structure is formed in the trench of the epitaxial layer; a drain layer is formed on the second surface of the substrate; The trench gate structure includes a source region formed within the epitaxial layer on both sides of the trench gate structure. The trench gate structure comprises: a gate formed within the trench, wherein the bottom of the gate has a concave curved surface, and the cross-section of the bottom of the gate has a dovetail or arrowhead profile; a gate oxide layer formed between the gate and the sidewall of the trench; and a bottom dielectric layer formed between the gate and the bottom surface of the trench.

7. The trench power element as claimed in claim 6, wherein the gate is a single gate or a split gate.

8. The trench power element as claimed in claim 7, wherein an isolation layer is provided between the discrete gates.

9. The trench power device as claimed in claim 6, wherein the material of the bottom dielectric layer includes silicon oxide, silicon nitride, or metal oxide.

10. The trench power device as claimed in claim 6, wherein the substrate material includes Si, SiC, GaN, or GaAs.

11. The trench power device as claimed in claim 6, wherein the substrate material includes a glass substrate or a sapphire substrate.

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