High temperature silicon-on-insulator pressure sensor technology

Abstract

In this paper the recent development of a high sensitivity high temperature Silicon-On-Insulator (SOI) piezoresistive sensor technology that provides pressure sensing, temperature sensing, and feedback and bias resistor networks all integrated on a single miniature chip that measures only 0.23 cm software (90 mils square) is reported. This advanced sensor technology also provides sheet resistivities of approximated 3 times greater than conventional bulk silicon sensors while maintaining the same dopant concentration of the p-type resistor elements. The new chip design features a high impedance 30 K/spl Omega/ pressure bridge which provides a full scale output of 200 milli-volt per volt of excitation. This corresponds to a /spl Delta/R/R gage factor of 0.20. Also featured is a high impedance 60 K/spl Omega/ temperature bridge with an output sensitivity of 1.2 milli-volt per /spl deg/C per volt of excitation. This high temperature SOI sensor technology complements Honeywell's HTMOS high temperature electronics product line which provides both analog devices (including quad amplifiers and switches, fluxes, A/D's, and voltage references) and digital devices (including SRAMs, microcontrollers and clock generators) with operation up to 300/spl deg/C. This dual capability of high temperature sensors and high temperature electronics provides all the required functional blocks needed for designing complete sensor systems for an array of high temperature applications.