MOSFETs with high mobility channel materials and higher-k/metal gate stack

Integration of lanthanum lutetium oxide (LaLuO₃) with a κ value of 30 is demonstrated on high mobility biaxially tensile strained Si (sSi) and compressively strained SiGe for fully depleted n/p-MOSFETs as a gate dielectric. N-MOSFETs on sSi fabricated with a full replacement gate process indicated very good electrical performance with steep subthreshold slopes of ~72 mV/dec and I_on/I_off ratios up to 10⁹. Strained SOI (sSOI) channel devices show higher electron mobility of 385 cm²/Vs compared to the reference device on SOI which has a mobility of 188 cm²/Vs. P-MOSFETs fabricated on sSi/Si_0.5Ge_0.5/sSOI heterostructure with a gate first process showed a subthreshold swing of 92 mV/dec and an I_on/I_off ratio of 10⁵. The extracted hole mobilities are similar to the reference device with HfO₂ as gate dielectric, and are much higher than the hole mobilities in Si.