Browse Prior Art Database

Semiconductor Temperature Sensor

IP.com Disclosure Number: IPCOM000095054D
Original Publication Date: 1965-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Gardner, EE: AUTHOR

Abstract

The temperature sensor is a resistor element having an epitaxial layer of semiconductor material mounted on semiconductor substrate. The correlation between change of impedance of the resistor element with a change in temperature is utilized to accurately determine absolute temperature of various environments.

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Semiconductor Temperature Sensor

The temperature sensor is a resistor element having an epitaxial layer of semiconductor material mounted on semiconductor substrate. The correlation between change of impedance of the resistor element with a change in temperature is utilized to accurately determine absolute temperature of various environments.

An epitaxial layer 1 and 2 of the proper resistivity and thickness is initially grown on semiconductor substrate 3 of the opposite type by standard techniques. The layer is preferably grown on the 100 crystal plane orientation. Such minimizes changes of resistance due to strain i. e., piezoresistive effect, caused by the differential expansion coefficient of silicon and the material on which the sensor is mounted. Layer portion 2 is separated from the rest of layer 1 by groove 4, which is etched down to the substrate. Dimensions W, L and t of layer 2 are dictated by the resistivity of the epitaxial material and the desired resistance of the sensor. Ohmic contacts 5 are provided on each end of the sensor to which electrical leads are attached.

While the dimensions of the sensor can be varied to suit individual requirements, the resistor portion of the sensor is typically 40 to 60 mils in length, 5 to 60 mils in width, with an epitaxial layer thickness of from, 3 to 7 mils in thickness. In general, the sensors having such dimensions have a minimum sensitivity of 4.5 ohms per degree F and a maximum resistance of 4500 ohms at th...