Fabrication of trench DMOS device having thick bottom shielding oxide
First Claim
1. A semiconductor device comprising:
- a semiconductor layer;
a trench formed in the semiconductor layer;
a conductive structure formed in the trench, the conductive structure having a top portion and a bottom portion electrically insulated from the semiconductor layer by a first insulating layer and a second insulating layer respectively, wherein the top portion is wider than the bottom portion and wherein a thickness of the second insulating layer proximate sidewalls of the trench between the bottom portion of the conductive structure and the sidewalls of the trench is T1 and a thickness of the second insulating layer proximate a bottom of the trench between the bottom portion of the conductive structure and the bottom of the trench is T2, wherein T2 is different from T1.
0 Assignments
0 Petitions
Accused Products
Abstract
Semiconductor device fabrication method and devices are disclosed. A device may be fabricated by forming in a semiconductor layer; filling the trench with an insulating material; removing selected portions of the insulating material leaving a portion of the insulating material in a bottom portion of the trench; forming one or more spacers on one or more sidewalls of a remaining portion of the trench; anisotropically etching the insulating material in the bottom portion of the trench using the spacers as a mask to form a trench in the insulator; removing the spacers; and filling the trench in the insulator with a conductive material. Alternatively, an oxide-nitride-oxide (ONO) structure may be formed on a sidewall and at a bottom of the trench and one or more conductive structures may be formed in a portion of the trench not occupied by the ONO structure.
-
Citations
9 Claims
-
1. A semiconductor device comprising:
-
a semiconductor layer; a trench formed in the semiconductor layer; a conductive structure formed in the trench, the conductive structure having a top portion and a bottom portion electrically insulated from the semiconductor layer by a first insulating layer and a second insulating layer respectively, wherein the top portion is wider than the bottom portion and wherein a thickness of the second insulating layer proximate sidewalls of the trench between the bottom portion of the conductive structure and the sidewalls of the trench is T1 and a thickness of the second insulating layer proximate a bottom of the trench between the bottom portion of the conductive structure and the bottom of the trench is T2, wherein T2 is different from T1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification