Simultaneous and Independent Measurement of Stress and Temperature Using a Single Field-Effect Transistor Structure

This paper reports on the simultaneous and independent measurement of mechanical stress and temperature using p- and n-channel field-effect transistor structures with multiple drain/source contacts fabricated in a commercial complementary metal-oxide-semiconductor technology. The respective average stress sensitivities of of three p-channel devices and 66 of two n-channel devices at room temperature originate from the shear piezoresistance effect, also termed pseudo-Hall effect, of the inversion layer carriers. The stress sensitivities show very small average temperature coefficients (TCs) of 1127 and 431 ppm/K for the p- and n-channel devices, respectively. Temperature values were obtained from the temperature-dependent threshold voltage . Robust values were extracted from the second-order transconductance smoothed using a new variant of Tikhonov's regularization method. With both types of devices, the obtained by this procedure was found to be stress insensitive in the range of stresses from 0 to 20.4 MPa. Between 25 and 150 , depends linearly on temperature, with average slopes of 1.67 and for p- and n-channel devices, respectively. Device-to-device variations of the temperature sensitivity and its slope suggest the use of a two-point calibration. With only a one-point calibration, a temperature uncertainty of less than 3 over a temperature range of 100 is achieved.