Polycrystalline silicon pressure transducer

A semiconductor pressure transducer having a thin vapor deposited polycrystalline silicon diaphragm providing an extremely sensitive and temperature stable device, said pressure transducer comprising:

• a monocrystalline silicon wafer serving as a supporting base member for said pressure transducer, said base member having two major end surfaces and an aperture extending therebetween;
• an etch-resistant layer of silicon dioxide on one of said base member end surfaces, said etch-resistant layer having a crystallographic structure so as to promote vapor deposition of polycrystalline silicon thereon;
• a thin, vapor deposited intrinsic polycrystalline silicon film on said etch-resistant layer and covering said aperture in said base member thereby providing an extremely sensitive pressure responsive diaphragm bridging said aperture, said polycrystalline silicon diaphragm being less than about 10 microns thick and having a resistivity of at least 10.sup.6 ohm-centimeters, said diaphragms being free of any material having a dissimilar coefficient of thermal expansion thereby providing improved temperature stability for said pressure transducer;
• an elongated doped region formed in said polycrystalline silicon diaphragm as a diameter thereof providing a pressure responsive resistor for said pressure transducer, said resistor being electrically isolated by the surrounding high resistivity polycrystalline silicon;
• and
• means for making electrical connection to said resistor thereby providing electrical access to said pressure transducer.