Improved Electrical Characteristics of Ge p-MOSFET with Ti-GeOx Interfacial Layer by in-situ Plasma-enhanced Atomic Layer Deposition

In this study, we successfully investigated Hf-based gate stacks with
$\text{Ti}-\text{GeO}_{\mathrm{x}}$
interfacial layer (IL) on a Ge channel p-MOSFET. The results revealed that thicker
$\text{TiGeO}_{\mathrm{x}}$
ILs could reduce interface trap density and leakage current. The X-ray photoelectron spectroscopy (XPS) analyses indicated fewer Ge-O bonds and O-Ge-O bonds but more
$\text{Ti-GeO}_{\mathrm{x}}$
bonds when the IL was thicker. Meanwhile, lower leakage current and higher mobility were observed by using Hf-based gate stack with
$\text{Ti-GeO}_{\mathrm{x}}$
IL on a Ge channel p-MOSFET.