High voltage thin film transistor having a linear doping profile
First Claim
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1. A high voltage, semiconductor-on-insulator electronic device, comprising:
- a substrate;
a first insulating layer disposed on the substrate, the first insulating layer having a first insulating layer thickness;
a semiconductor layer disposed on the first insulating layer, wherein the semiconductor layer further comprises in lateral sequence a source region, a body region, a thin drift region and a drain region;
a gate oxide layer disposed atop the source, body and drift regions;
a gate region disposed atop the gate oxide layer;
a second insulating layer next to the gate oxide layer and the gate region and disposed atop the drift region;
wherein the drift region has a length L, describing the distance between the body region and the drain region along the drift region, a drift region thickness perpendicular to said length L, and a substantially linear doping profile along the length L of said drift region, from a minimum value the drift region adjacent to the body region, to a maximum value adjacent to the drain region;
wherein length L is substantially in the range of 10 microns to 60 microns;
wherein the drift region thickness is less than or equal to about 1 micron;
wherein the substantially linear doping profile is described at any point along the length of the drift region X microns distant from the body region by the relationship;
space="preserve" listing-type="equation">Q(X)=Q(0)+(X/L)Q.sub.maxwhere Q(0) is the minimum number of dopant ions per unit area in the drift region adjacent to the body region, and is substantially in the range of 1×
1011 /cm2 to about 1×
1012 /cm2 ;
Qmax is substantially in the range of 5×
1012 /cm2 to about 2×
1013 /cm2, and Q(0)+Qmax is the maximum number of dopant ions per unit area adjacent to the drain region; and
wherein the combination of the drift region having a thickness less than or equal to 1 micron and the substantially linear doping profile provides a higher breakdown voltage for the device.
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Abstract
The present invention is directed to a thin film transistor having a linear doping profile between the gate and drain regions. This is constructed in a particular manner in order to achieve a thin film transistor having a significantly high breakdown voltage of the order of 700 to 900 volts, much greater than that achieved in the prior art.
49 Citations
8 Claims
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1. A high voltage, semiconductor-on-insulator electronic device, comprising:
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a substrate; a first insulating layer disposed on the substrate, the first insulating layer having a first insulating layer thickness; a semiconductor layer disposed on the first insulating layer, wherein the semiconductor layer further comprises in lateral sequence a source region, a body region, a thin drift region and a drain region; a gate oxide layer disposed atop the source, body and drift regions; a gate region disposed atop the gate oxide layer; a second insulating layer next to the gate oxide layer and the gate region and disposed atop the drift region; wherein the drift region has a length L, describing the distance between the body region and the drain region along the drift region, a drift region thickness perpendicular to said length L, and a substantially linear doping profile along the length L of said drift region, from a minimum value the drift region adjacent to the body region, to a maximum value adjacent to the drain region; wherein length L is substantially in the range of 10 microns to 60 microns; wherein the drift region thickness is less than or equal to about 1 micron; wherein the substantially linear doping profile is described at any point along the length of the drift region X microns distant from the body region by the relationship;
space="preserve" listing-type="equation">Q(X)=Q(0)+(X/L)Q.sub.maxwhere Q(0) is the minimum number of dopant ions per unit area in the drift region adjacent to the body region, and is substantially in the range of 1×
1011 /cm2 to about 1×
1012 /cm2 ;
Qmax is substantially in the range of 5×
1012 /cm2 to about 2×
1013 /cm2, and Q(0)+Qmax is the maximum number of dopant ions per unit area adjacent to the drain region; andwherein the combination of the drift region having a thickness less than or equal to 1 micron and the substantially linear doping profile provides a higher breakdown voltage for the device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification