OFF-AXIS SENSOR ROSETTES FOR MEASUREMENT OF THE PIEZORESISTIVE COEFFICIENTS OF SILICON

In this paper, experimental calibration results for the piezoresistive coefficients of silicon as a function of temperature are presented. M easurements have been performed using a test chip incorporating a new off-axis 0-45-degrees-90-degrees rosette design. This rosette requires the application of only uniaxial stress for measurement of the three individual piezoresistive coefficients of silicon: pi11, pi12, and pi4 4. Of even greater potential import, this rosette yields inherently te mperature compensated values of the coefficients pi44 and pi(D) = (pi1 1 - pi12). P-type off-axis rosettes have been characterized as a funct ion of temperature, and values for the temperature dependencies Of pi4 4 and pi(D) are reported. The coefficients pi44 in p-type silicon and pi(D) in n-type silicon are needed for an optimized stress sensor on ( 100) silicon.