Self-aligned contact for trench MOSFET
First Claim
Patent Images
1. A trench metal oxide semiconductor field effect transistor (MOSFET) structure on a substrate, comprising:
- a first trench and a second trench on the substrate, wherein both the first trench and the second trench are lined with a gate dielectric layer and filled with gate polysilicon;
a self-aligned source contact between the first trench and the second trench, wherein the self-aligned source contact is connected to a source metal;
a gate contact above the first trench, wherein the gate contact is connected to a gate metal and to the gate polysilicon in the first trench; and
a source region surrounding the self-aligned source contact,wherein the source region comprises a convex surface and a curved surface directly above the convex surface.
1 Assignment
0 Petitions
Accused Products
Abstract
The process methods and structures mentioned above for creating a trench MOSFET enables self-aligned contacts to be formed to allow decreasing pitch size for trench MOSFET. The self-aligned contacts are formed by etching exposed silicon areas without using lithographical mask and alignment. As a result, the allowance for alignment can be saved and the pitch size can be decreased.
-
Citations
20 Claims
-
1. A trench metal oxide semiconductor field effect transistor (MOSFET) structure on a substrate, comprising:
-
a first trench and a second trench on the substrate, wherein both the first trench and the second trench are lined with a gate dielectric layer and filled with gate polysilicon; a self-aligned source contact between the first trench and the second trench, wherein the self-aligned source contact is connected to a source metal; a gate contact above the first trench, wherein the gate contact is connected to a gate metal and to the gate polysilicon in the first trench; and a source region surrounding the self-aligned source contact, wherein the source region comprises a convex surface and a curved surface directly above the convex surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A trench metal oxide semiconductor field effect transistor (MOSFET) structure on a substrate, comprising:
-
a first trench, a second trench, and a third trench on the substrate, wherein the first trench, the second trench, and the third trench are lined with a gate dielectric layer and filled with gate polysilicon; a first self-aligned source contact between the first trench and the second trench and a second self-aligned source contact between the second trench and the third trench, wherein both the first and the second self-aligned source contacts are connected to a source metal; a gate contact above the first trench, wherein the gate contact is connected to a gate metal and to the gate polysilicon in the first trench; and a first source region surrounding the first self-aligned source contact and a second source region surrounding the second self-aligned source contact, wherein both the first and the second source regions are convex-shaped, and wherein the first source region and the second source region are above an upper surface of the gate polysilicon in the second trench. - View Dependent Claims (12, 13)
-
-
14. A transistor comprising:
-
a substrate doped with a first type dopant; an epitaxial layer over the substrate, the epitaxial layer having a doped portion doped with a second type dopant and a source region doped with the first type dopant; a first gate structure in the epitaxial layer, at least a portion of the first gate structure being adjacent to the doped portion, the first gate structure comprising; a gate electrode; and a gate dielectric layer sandwiched between the gate electrode and the epitaxial layer; a second gate structure in the epitaxial layer, at least a portion of the second gate structure being adjacent to the doped portion, the second gate structure comprising; a gate electrode; and a gate dielectric layer sandwiched between the gate electrode and the epitaxial layer; a source contact between the first gate structure and the second gate structure, the source region being adjacent to the source contact and convex-shaped with a convex surface facing the substrate; and a gate contact electrically coupled to the gate electrode of the first gate structure and the gate electrode of the second gate structure, wherein the source region is above an upper surface of the second gate structure. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
Specification