Positive bias temperature instability degradation of InGaAs n-MOSFETs with Al2O3 gate dielectric

CP measurements show that PBTI stress induced interface trap area density ΔN_it in InGaAs/Al₂O₃ n-MOSFET is very small and has power law time evolution At^0.22 in the stress phase, and is partially recovered in the recovery phase. However the DC I_s-V_g measurements show large degradations of negative ΔV_g and sub-threshold swing S in the sub-threshold region and are recovered in the recovery phase, also show degradation of positive ΔV_g in the on-current region and continuing degradation in the recovery phase until reaching a stable state. The I_s-V_g degradation is mainly contributed by generation of near interface slow oxide traps under stress with recoverable donor trap energy density ΔD_SOX^DONOR in the InGaAs energy gap with a tail extended to the conduction band energy, and permanent acceptor trap energy density ΔD_SOX^ACCEPTOR in the conduction band energy with a tail extended to the energy gap. This trap model explains all experimental details perfectly.