Thermally robust phosphorous nitride interface passivation for InGaAs self-aligned gate-first n-MOSFET integrated with high-k dielectric

Plasma-based PH₃ passivation technique is extensively studied for the surface passivation of InGaAs substrate prior to high-k deposition. The comparative analysis reveals that the striking improvement is achieved when a stable covalent-bond P_xN_y layer forms at the interface during plasma PH₃-passivation. We report that P_xN_y passivation layer improves thermal stability of high-k/InGaAs gate stack up to 750°C, which enables successful implementation of InGaAs MOSFETs by self-aligned gate-first process. By adopting P_xN_y passivation on InGaAs with MOCVD HfAlO and metal gate stack, we achieved subthreshold slope of 98mV/dec, G_m=378mS/mm at V_d=1V, and effective mobility of 2557cm²/Vs at E_eff=0.24MV/cm.