Experimental Investigation of Border Trap Generation in InGaAs nMOSFETs With $\hbox {Al}_{2}\hbox {O}_{3}$ Gate Dielectric Under PBTI Stress

The reliability performance of InxGa_1-xAs n-type metal-oxide-semiconductor field-effect transistors with Al₂O₃ gate dielectric under positive-bias temperature instability stress is investigated systematically. A model of stress-induced border traps was proposed to interpret all charge pumping and I-V experimental results excellently. The stress-induced border traps include recoverable donor traps and permanent acceptor traps with respective energy densities ΔD_SOX^Donor(E) and ΔD_SOX^Acceptor(E) . The shapes of ΔD_SOX^Donor(E) and ΔD_SOX^Acceptor(E) have been extracted from experimental data. ΔD_SOX^Acceptor(E) mainly distributes in the conduction band of InGaAs with a tail extending to the mid-gap, whereas ΔD_SOX^Donor(E) has a large distribution inside the energy gap and extends to the conduction band. The high density of ΔD_SOX^Donor(E) in the energy gap induces large degradation in the off-current, which is particularly serious when the In composition x is raised to 0.65.