Experimental Determination of the Temperature Dependency of the Elastic Constants of Degenerately Doped Silicon

We study experimentally the temperature dependence of the elastic constants of degenerately doped silicon as a function of the doping level. First and second order thermal coefficients of the elastic constants are extracted from the temperature dependent resonance frequencies of a set of MEMS resonators fabricated on phosphorus, arsenic and boron doped wafers having maximum doping levels of 7.5 × 10 19 cm -3 , 2.5 × 10 19 cm -3 and 3 × 10 19 cm -3 , respectively. Trends in the behavior of the thermal coefficients as a function of doping are identified and discussed.