Improvement of SiGe MOS interface properties with a wide range of Ge contents by using TiN/Y2O3 gate stacks with TMA nassivation

Abstract

We demonstrate the low interface trap density at SiGe p-MOS interfaces with TiN/Y2O3gate stacks by employing the Trimethylaluminum (TMA) passivation. PMA temperature is optimized to maximize scavenging of GeOx. The impact of the gate electrode among TiN, Al, Au and W is studied for Y2O3/SiGe interfaces. The TiN/Y2O3/ SiGe interfaces with PMA at 450°C minimize interface trap density $(\text{D}_{\text{it}})$, hysteresis and gate leakage current. TMA passivation is found to further improve the interfacial pronerties. The record-low minimum $\text{D}_{\text{it}}$ of $2.7\text{x}10^{10} 5.4{\text{x}}10^{10},1.7\text{x}10^{11},2.0\text{x}10^{11},7.4\text{x}10^{11}$ and $4.2\text{x}10^{12}\text{eV}^{-1}\text{cm}^{-2}$ are obtained for SiGe MOS interfaces with the Ge contents of 0.13, 0.22, 0.32, 0.38, 0.49, and 0.62, respectively.