Patent ID: 8680609
Filing Date: 2014-03-25
Classification: H01L

Abstract:
1. A depletion mode trench semiconductor device, comprising: a substrate having a first type conductivity; a drift epitaxial layer having the first type conductivity, wherein the drift epitaxial layer is disposed on the substrate; a base doped region having a second type conductivity, wherein the base doped region is disposed in the drift epitaxial layer; a trench gate structure, disposed in a trench extending into the drift epitaxial layer and on a side of the base doped region, wherein the trench comprises a horizontal, flat bottom surface and a vertical outer sidewall; a source doped region having the first type conductivity, wherein the source doped region is disposed in the base doped region and adjacent to the trench gate structure; a contact doped region having the second type conductivity, wherein the contact doped region is disposed in the base doped region and adjacent to the source doped region; an inversion layer having the first type conductivity, wherein the inversion layer is disposed outside of the trench in the base doped region and the inversion layer encompasses the vertical outer sidewall of the trench; a diffused region of the first conductivity type in the drift epitaxial layer, wherein the diffused region encompasses the horizontal, flat bottom surface of the trench and extends to the vertical outer sidewall of the trench to merge with the inversion layer; a dielectric layer covering the trench gate structure; and a source conductive line electrically connecting with the source doped region and the contact doped region.