The piezoresistive behavior of nc-diffusions in monocrystalline CMOS-processed silicon is calibrated by independent measurements of the three piezoresistive pi-coefficients. These are obtained by subjecting integrated resistors on test chips to three distinct stress fields, (a) using a four-point bending bridge and (b) applying a pressure perpendicular to the die surface. This represents a novel method of calibrating stress sensor test chips. The experimentally induced stresses are computed by finite element analysis. Values of pi(11) = (-3.68 +/- 0.24) x 10(-4) MPa-1, pi(12) = (2.24 +/- 0.18) x 10(-4) MPa-1, and pi(44) = (-1.59 +/- 0.09) x 10(-4) MPa-1 are obtained. [References: 8]
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