High temperature hetero-epitaxial pressure sensor

Claim 2

A high temperature hetero-epitaxial piezoresistive pressure sensor comprising: a single crystal silicon substrate, the silicon having a bandgap of about 1 eV; a thin-film epitaxial single crystal layer comprised of a wider bandgap semiconductor than said silicon substrate epitaxially grown on said silicon substrate, said semiconductor also being of a type having large piezoresistive effects; diffused or ion implanted piezoresistive resistors in said wider bandgap semiconductor layer; and, a cup like depression in said substrate forming a diaphragm at the location of said piezoresistive resistors.

Claim 3

The sensor according to claim 1 in which the epitaxial layer is GaAs.

Claim 4

The sensor according to claim 2 in which the piezoresistive resistors are p-type and the epitaxial layer is semi-insulating or n-type.

Claim 5

The sensor according to claim 1 in which the epitaxial layer is Al x Ga 1-x As where 0<x≦1.

Claim 6

The sensor according to claim 4 in which the x>0.5 piezoresistive resistors are p-type.

Claim 7

The sensor according to claim 4 in which x>0.5 and the piezoresistive resistors are n-type.

Claim 8

The sensor according to claim 2 in which the GaAs layer is about 2 microns in thickness and in which the piezoresistive means are implanted into the GaAs layer to a depth of about 1 micron.

Claim 9

The sensor according to claim 1 in which the wider bandgap semiconductor layer is about 2 microns in thickness and into which the piezoresistive means are ion implanted to a depth of about 1 micron.

Claim 10

The sensor according to claim 1 in which the epitaxial layer has a piezoresistive coefficient >50×10 -12 cm 2 /dyne.

Claim 11

A high-temperature hetero-epitaxial piezoresistive pressure sensor comprising: a single crystal silicon substrate, the silicon having a bandgap of about 1 eV; a thin-film epitaxial single crystal layer of β-SiC having a wider bandgap semiconductor than said silicon substrate epitaxially grown on said silicon substrate, said semiconductor also being of a type having large piezoresistive effects; diffused or ion implanted piezoresistive resistors in said wider bandgap semiconductor layer; and, a cup like depression in said substrate forming a diaphragm at the location of said piezoresistive resistors.

Claim 12

A high-temperature hetero-epitaxial piezoresistive pressure sensor comprising: a single crystal silicon substrate, the silicon having a bandgap of about 1 eV; a thin-film epitaxial single crystal layer of β-SiC having a wider bandgap semiconductor than said silicon substrate epitaxially grown on said silicon substrate, said semiconductor also being of a type having large piezoresistive effects; diffused or ion implanted piezoresistive resistors in said wider bandgap semiconductor layer; and, a cup like depression in said substrate forming a diaphragm at the location of said piezoresistive resistors.