Investigations on the Nitride Interface Engineering at HfO2/Ge stacks for MOS devices

Abstract

Passivation layer influenced structural and electrical properties of Ge MOS devices have been reported. Nitride layer was deposited on Ge substrate with rapid thermal annealing before HfO2 deposition. XRD spectra revealed that there was no difractional peak related to HfO2 on Ge substrate after annealing. HREM images showed that there was clear interface at annealed HfO2/Ge stacks. C-V plots revealed that, intentionally formed interfacial nitride layer showed significant improvement in the interface quality between HfO2 and Ge. I-V characteristics showed that Ge devices showed about one order lower leakage current densities than Si devices. All of these observations might be due to the process of surface passivation on Ge substrate.