Impact of ge content on flicker noise behavior of strained-SiGe p-type metal-oxide-semiconductor field-effect transistors

The DC characteristic and low-frequency (1=f ) noise behavior of strained-Si_1-xGe_x p-type metal-oxide-semiconductor field-effect transistors (pMOSFETs) with 15 and 30% Ge channel have been investigated and compared with those of Si control counterparts. Enhancement in effective hole mobility of 24 and 45% were obtained in strained-SiGe devices with a 15 and 30% Ge channel, respectively. The strained-SiGe pMOSFETs with a higher Ge buried channel exhibit lower 1=f noise, indicating that more carriers are confined in the SiGe channel and interface scattering is remote. Moreover, we also found that the Ge concentration plays an important role in the noise mechanism. A new observation shows that carrier number fluctuation is more suitable for interpreting the mechanism of 1=f noise in strained-SiGe devices with 30% Ge channel, while both number fluctuation noise and mobility fluctuation noise are likely to contribute to the characteristics of SiGe pMOSFETs with 15% Ge and the Si control device.