Evaluation of the piezoresistive properties of non-single-crystal Si film

An improved means of evaluating piezoresistive properties (PR) of Si thin films is to measure the ratio of the longitudinal effect πl, to the transverse effect πt, in addition to the gauge factor, temperature coefficient of resistance and temperature coefficient of gauge factor. The PR made by various processes were evaluated. The property of p-type µc-Si:F:H made by d.c. glow discharge with a high power density and at 300–350°C is excellent. This film showed similar symmetry to that of single Si; πl=-2πt