Carrier concentration dependence and temperature dependence of mobility in silicon (100) N-channel inversion layers at low temperatures

Abstract

The carrier concentration ( N s ) dependence of electron mobility in Si (100) inversion layers has been measured at temperatures T = 1.5−70K for high- and low-mobility MOSFETs. An extrinsic term is observed in the T-dependent part of the scattering probability, τ −1 T . At T = 4.4 K, τ −1 T depends on N s as N −1.9 s in low mobility samples. In high-mobility samples, τ −1 T increases with increasing N s in high N s region while τ −1 T ∝ N −1.6 s in low N s region. The N s -dependence of τ −1 T becomes weaker with increasing T in both of low- and high-mobility samples. At N s = 3 × 10 12 cm −2, τ −1 T depends on T as T 1.8 in low-mobility samples and τ −1 T ∝ T 2.0 in high- mobility samples at T 5 K.