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Semiconductor pressure sensor

  • US 4,813,272 A
  • Filed: 07/31/1987
  • Issued: 03/21/1989
  • Est. Priority Date: 08/01/1986
  • Status: Expired due to Fees
First Claim
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1. In a semiconductor pressure sensor including a silicon single crystal elastic substrate whose surface tension changes in accordance with the pressure applied thereto, a strain gage defined by a P-type diffused layer formed on the surface of said substrate, a bridge circuit including said strain gage, a constant-current circuit for supplying a driving current to said bridge circuit, and an amplifier circuit for amplifying an output from the output terminals of said bridge circuit to form an output signal,the improvement comprising:

  • strain gages in said bridge circuit which are diffused resistor layers having a surface impurity concentration within the range from 2.3×

    1018 to 2.5×

    1018 atoms/cm3 ; and

    thermistor means in said constant-current circuit, the thermistor means having a temperature-resistance characteristic for cancelling a temperature-resistance characteristic of said diffused resistor layers by selection of a B constant of the thermistor within the range from 1400K to 2400K, thereby effecting temperature compensation of sensitivity.

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