Effect of forming gas annealing on the inversion response and minority carrier generation lifetime of n and p-In_0.53Ga_0.47As MOS capacitors

In_0.53Ga_0.47As MOS capacitors with a range of Al₂O₃ oxide thickness values were examined using multi-frequency capacitance-voltage and conductance-voltage characterization for n and p-type In_0.53Ga_0.47As epitaxial layers. The samples exhibited a minority carrier response consistent with surface inversion for both n and p-type In_0.53Ga_0.47As MOS structures. An equality between the peak magnitude of the frequency scaled conductance, G/ω, and the derivative of capacitance with frequency, -ωdC/dω in strong inversion allows estimation of accurate C_ox values for the varying thickness MOS devices. Minority carrier generation lifetimes, τ_g, were extracted from the experimentally measured transition frequencies, ω_m, through physics based a.c. simulations. It was observed that τ_g was reduced following a post-metallization 275 °C forming gas anneal treatment over both n and p-In_0.53Ga_0.47As. This is indicative of an improvement in the In_0.53Ga_0.47As quality by means of hydrogen passivation of the mid-gap bulk defects responsible for the observed minority carrier response.