High speed trench DMOS
First Claim
Patent Images
1. A method for forming a trench DMOS, comprising the steps of:
- providing an article comprising a substrate of a first conductivity type and a body region of a second conductivity type, said article having a trench which extends through said body region and said substrate;
depositing a gate oxide layer in the trench;
forming a gate in the trench, said gate having at least one layer comprising a material selected from the group consisting of polycide and refractory metals; and
forming a source region in the body region;
wherein the source region is formed after the gate oxide layer is deposited.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for making trench DMOS is provided that utilizes polycide and refractory techniques to make trench DMOS which exhibit low gate resistance, low gate capacitance, reduced distributed RC gate propagation delay, and improved switching speeds for high frequency applications.
33 Citations
36 Claims
-
1. A method for forming a trench DMOS, comprising the steps of:
-
providing an article comprising a substrate of a first conductivity type and a body region of a second conductivity type, said article having a trench which extends through said body region and said substrate;
depositing a gate oxide layer in the trench;
forming a gate in the trench, said gate having at least one layer comprising a material selected from the group consisting of polycide and refractory metals; and
forming a source region in the body region;
wherein the source region is formed after the gate oxide layer is deposited.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
forming a patterned BPSG layer over said trench.
-
-
22. The method of claim 21, wherein the pattered BPSG layer is formed over the trench with a flow temperature cycle ranging from about 900 to about 950°
- C.
-
23. The method of claim 1, wherein the step of forming a gate in the trench includes the steps of filling the trench with polysilicon, and depositing on the polysilicon a layer comprising a material selected from the group consisting of polycide and refractory metals.
-
24. A method for making a trench DMOS, comprising the steps of:
-
providing a substrate of a first conductivity type;
forming a body region on the substrate, said body region having a second conductivity type;
forming a masking layer defining at least one trench;
forming the trench defined by the masking layer, said trench extending through the body region and the substrate;
forming a gate in the trench, said gate comprising a first layer comprising undoped polysilicon, a second layer comprising doped polysilicon, and a third layer comprising a material selected from the group consisting of polycide and refractory metals; and
forming a first source region of the first conductivity type in the body region adjacent to the trench. - View Dependent Claims (25, 27, 28)
forming a second source region of a third conductivity type adjacent to said first source region.
-
-
27. The method of claim 24, wherein said trench is covered with an insulating layer before said gate is formed.
-
28. The method of claim 27, wherein said insulating layer is a gate oxide layer.
-
26. The method of claim wherein said first source region is an n+ source, and wherein said second source region is a p+ source.
-
29. A method for forming a trench DMOS transistor cell, comprising the steps of:
-
providing an article comprising a substrate of a first conductivity type and a body region of a second conductivity type, said article having a trench which extends through said body region and said substrate;
forming a gate overlying said trench and said body region, said gate having at least one layer comprising a material selected from the group consisting of polycide and refractory metals;
placing a mask over the trench;
removing the unmasked portions of the gate; and
forming a first source region in the body region. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
forming a second source region of a third conductivity type.
-
-
34. The method of claim 29, wherein the first source region is an n+ source region.
-
35. The method of claim 33, wherein the first source region is an n+ source region, and wherein the second source region is a p+ source region.
-
36. The method of claim 29, wherein the step of forming the gate includes the steps of filling the trench with polysilicon, and depositing on the polysilicon a layer comprising a material selected from the group consisting of polycide and refractory metals.
Specification