Ni-salicided CMOS with a poly-SiGe/Al2O3/HfO2/Al2O3 gate stack

Ni-salicided MOSFETs with a gate stack of ALD Al2O3/HfO2/Al2O3 high-κ dielectric and poly-SiGe gate electrode were fabricated. The Si pMOSFETs with an EOT of 1.7 nm showed an expected gate leakage current reduction compared to SiO2 with the same EOT and a mobility around 20% lower than the universal curve. The strained SiGe surface-channel pMOSFETs with the same gate stack showed an enhanced current drive and hole mobility. The Si nMOSFETs, however, exhibited a degraded subthreshold slope and a lower current drive even compared with the Si pMOSFETs. Possible reasons for the degradation of Si nMOSFETs were discussed.