Low-Frequency Noise Characteristics in Strained-Si nMOSFETs

The low-frequency (LF) (1/f) noise mechanism of strained-Si nMOSFETs grown on relaxed Si
_1-x
Ge
_x
virtual substrates (VSs) has been investigated. It is found that the Si-cap thickness plays an important role in characterizing the 1/f noise mechanism. Ge out-diffusion effect and slight strain relaxation in Si-cap layer are responsible for the degradation of 1/f noise in strained-Si device with 10- and 20-nm-thick Si-cap, respectively. In addition, by choosing proper Si-cap thickness, experimental result shows that as Si-cap undergoes stronger tensile strain for higher Ge concentration VS, the correlated mobility fluctuation term in the modified carrier-number fluctuation model is more dominated for the 1/f noise