The future of high-K on pure germanium and its importance for Ge CMOS

A comparison between atomic layer chemical vapor deposition (ALCVD) and metal organic chemical vapor deposition (MOCVD) HfO2 layers on Ge indicate that ALCVD layers have some improved capacitor characteristics. An NH3 pre-treatment was essential to obtain MOS C-V characteristics for the deposited HfO2 layer. We also report for the first time, deep sub-micron Ge pFETs made in a silicon-like process flow with a directly etched metal gate stack on a HfO2 dielectric. The results indicate that for improving Ge devices, more understanding on the dopant diffusion control and the reduction of interface state density will be necessary.