A study of the chemical oxide/InP interface states

Metal-Insulator-Semiconductor (MIS) structures have been produced by chemical oxidation of InP surfaces. In MIS diodes fabricated without thermal annealing of the as-grown surface oxide, a considerable increase of the ideality factor was observed in highly oxidized samples. It is demonstrated that this phenomenon is partly related to the quality of the as-grown oxide. Two interfacial deep levels with activation energies and capture cross sections, E1=390 meV, σ1=2×10−17 cm2 and E2=510 meV, σ2=4×10−12 cm2, respectively, have been observed. After a detailed study, it has been shown that these two interfacial states originate from the transition region between the as-grown oxide and the InP substrate.