The low-frequency noise characteristics of p-type metal-oxide-semiconductor field effect transistors with a strained-Si_0.88Ge_0.12 channel grown on bulk Si and a PD-SOI substrate

Low-frequency noise properties have been investigated for SiGe p-type metal-oxide- semiconductor field effect transistors with different substrates using Si bulk and a partially depleted silicon-on-insulator (PD SOI). The electrical properties of SiGe PD SOI were enhanced in the subthreshold slope and drain induced barrier lowering. However, the low-frequency noise for the PD SOI was found to degrade significantly in terms of the power spectral density. The low frequency noise was observed to follow the typical 1/f ^γ(γ = 1) dependence in SiGe bulk devices, but abnormal changes with γ = 2 were revealed in the SiGe PD SOI. The difference of the noise frequency exponent was mainly attributed to generation-recombination by traps presented at the silicon-oxide interface of the SOI. Regardless of the degraded noise performance in the SOI structure, the low-frequency noise level remained well at an acceptable level by virtue of the effective carrier confinement in the SiGe channel.