Characterization of Slow Traps in SiGe MOS Interfaces by TiN/Y2O3 Gate Stacks

We have examined the slow electron and hole trap density at TiN/Y
₂
O
₃
/SiGe MOS interfaces. The effect of trimethylaluminum (TMA) pre-treatment before Y
₂
O
₃
deposition on the slow trap density has been studied. Also, the dependency of the slow trap density on Ge contents of SiGe has been systematically evaluated and the influence of the composition of interfacial layers (ILs) is examined. It is found that 10-cycle TMA treatment is effective to suppress the formation of slow traps attributable to Ge-O bonds in ILs. On the other hand, the density of electron and hole slow traps in the Y
₂
O
₃
/SiGe MOS interfaces increases with higher Ge content of SiGe, which can be explained by the formation of vacancy-related defects due to incorporation of Ge-O bonds into SiO
₂
IL networks.