Low-Frequency Noise Characterization of GeOx Passivated Germanium MOSFETs

The gate-stack quality of planar MOSFETs fabricated in Ge-on-Si substrates and passivated by a GeOx interfacial layer is evaluated by low-frequency noise analysis. It is shown that for both n- and p-channel transistors predominantly 1/f. noise (gamma similar to 1) has been observed, which originates from number and correlated mobility fluctuations. The oxide trap density and mobility scattering coefficient derived from the input-referred voltage noise power spectral density are demonstrated to be significantly higher for nMOSFETs than for pMOSFETs with the same gate-stack, which explains the low electron mobility.