Examination of physical origins limiting effective mobility of Ge MOSFETs and the improvement by atomic deuterium annealing

It is found that traps inside conduction and valence bands of Ge is the dominating factor of effective mobility reduction for Ge MOSFETs in high N_s region and that surface roughness scattering can quantitatively explain the Hall mobility, which is free from the trapping effects. It is also found that atomic deuterium PDA sufficiently reduces the trap density inside conduction band of Ge, resulting in enhancement of effective electron mobility. Record high effective electron mobility of 488 cm²/Vs has been realized at N_s=8×10¹² cm^-2 for Ge nMOSFETs with atomic deuterium PDA at 400°C.