High voltage thin film transistor having a linear doping profile

Claim 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: Q(X)=Q(0)+(X/L)Q.sub.max where 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 1×10 11 /cm 2 to about 1×10 12 /cm 2 ; Q max is substantially in the range of 5×10 12 /cm 2 to about 2×10 13 /cm 2 , and Q(0)+Q max 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.