High-Temperature Stable $\hbox{Ir}_{x}\hbox{Si}$ Gates With High Work Function on HfSiON p-MOSFETs

A novel 1000 $^{\circ}\hbox{C}$-stable $\hbox{Ir}_{x}\hbox{Si}$ gate on HfSiON is shown for the first time with full process compatibility to current very-large-scale-integration fabrication lines and proper effective work function of 4.95 eV at 1.6-nm equivalent-oxide thickness. In addition, small threshold voltages and good hole mobilities are measured in $\hbox{Ir}_{x}\hbox{Si/HfSiON}$ transistors. The 1000 $^{\circ}\hbox{C}$ thermal stability above pure metal (900 $^{\circ}\hbox{C}$ only) is due to the inserted 5-nm amorphous Si, which also gives less Fermi-level pinning by the accumulated metallic full silicidation at the interface.