Reliability of High-Mobility InGaAs Channel n-MOSFETs Under BTI Stress

The reliability performance of InxGa1-xAs n-MOSFETs with Al2O3 gate dielectric under positive-bias temperature instability stress is investigated. The following new phenomena are demonstrated: 1) There are high densities of fast interface traps N-it and slow oxide border traps N-SOX near the interface between InGaAs and Al2O3. The border traps are more fragile under stress, and therefore, the stress mainly induces border traps. 2) The stress-induced border traps consist of permanent acceptor traps and recoverable donor traps. Acceptor trap energy density Delta D-SOX(Acceptor) (E) is mainly distributed above the conduction band edge E-c of InGaAs with a tail extending to the midgap, whereas donor trap energy density Delta D-SOX(Donor) (E) has a large distribution inside the InGaAs energy gap with a tail extending to the conduction band. 3) Flicker noise variation after stress and its correlation to the acceptor and donor trap generation and recovery are demonstrated. 4) The recoverable donor traps induce the subthreshold slope and off-current degradation in the stress phase and recover in the recovery phase and also induce continuous degradation of on-current in the recovery phase. The permanent acceptor traps induce the transconductance and on-current degradation. The long-term device lifetime is mainly determined by the generation rate of the acceptor traps. 5) Comprehensive comparison between the Si and InGaAs MOSFETs' degradation behaviors under bias temperature instability stress is presented. The physical recovery of donor oxide traps in dielectric in InGaAs/Al2O3 has never been observed in a Si MOS structure, deserving special attention and further investigation.