Fully silicided NiSi gate on La₂O₃ MOSFETs

We have fabricated the fully silicided NiSi on La₂O₃ for n- and p-MOSFETs. For 900°C fully silicided CoSi₂ on La₂O₃ gate dielectric with 1.5 nm EOT, the gate dielectric has large leakage current by possible excess Co diffusion at high silicidation temperature. In sharp contrast, very low gate leakage current density of 2 × 10^-4 A/cm² at 1 V is measured for 400°C formed fully silicided NiSi and comparable with Al gate. The extracted work function of NiSi was 4.42 eV, and the corresponding threshold voltages are 0.12 and -0.70 V for respective n- and p-MOSFETs. Electron and hole mobilities of 156 and 44 cm²/V-s are obtained for respective n- and p-MOSFETs, which are comparable with the HfO₂ MOSFETs without using H₂ annealing.