Semiconductor device
First Claim
1. A semiconductor device having a field effect transistor, said field effect transistor comprises:
- a semiconductor substrate;
a semiconductor layer formed on said semiconductor substrate;
a trench formed in said semiconductor layer;
a gate electrode provided within said trench via an gate insulating film intervening therebetween;
an insulating film provided on an upper portion of said gate electrode in the interior of said trench;
a source region provided on the side of said trench in an upper surface of said semiconductor layer;
a source electrode provided on upper portions of said insulating film and said source region;
a drain region provided under said trench; and
a drain electrode provided on a back surface of said semiconductor substrate, wherein said insulating film provides an electrical insulation of said gate electrode from said source electrode, wherein said semiconductor device comprises a cell portion and a terminal end provided in a periphery of said cell portion, and has said field effect transistor in said cell portion and has a trench in said terminal end, and wherein a bottom surface of the trench provided on said terminal end is positioned to be lower than a bottom surface of the trench of said field effect transistor provided on said cell portion.
2 Assignments
0 Petitions
Accused Products
Abstract
The leakage current generated due to the extension of the depleted layer to the end of the chip is reduced. In MOSFET 100, the depths of the trenches 112 in the gate pad portion 50 and the circumference portion 70 are larger than the depths of the trenches 111 in the cell region 60. Therefore, the depleted layer extending from the cell region 60 along the direction toward the gate pad portion 50 or the direction toward the circumference portion 70 is blocked by the presence of the trench 112. In other words, an extending of the depleted layer can be terminated by disposing the trench 112, so as to avoid reaching the depleted layer to the end of the semiconductor chip. Accordingly, a leakage current generated from the cell region 60 along the direction toward the end of the semiconductor chip can be reduced.
-
Citations
6 Claims
-
1. A semiconductor device having a field effect transistor, said field effect transistor comprises:
-
a semiconductor substrate;
a semiconductor layer formed on said semiconductor substrate;
a trench formed in said semiconductor layer;
a gate electrode provided within said trench via an gate insulating film intervening therebetween;
an insulating film provided on an upper portion of said gate electrode in the interior of said trench;
a source region provided on the side of said trench in an upper surface of said semiconductor layer;
a source electrode provided on upper portions of said insulating film and said source region;
a drain region provided under said trench; and
a drain electrode provided on a back surface of said semiconductor substrate, wherein said insulating film provides an electrical insulation of said gate electrode from said source electrode, wherein said semiconductor device comprises a cell portion and a terminal end provided in a periphery of said cell portion, and has said field effect transistor in said cell portion and has a trench in said terminal end, and wherein a bottom surface of the trench provided on said terminal end is positioned to be lower than a bottom surface of the trench of said field effect transistor provided on said cell portion. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification