On the electrical properties of the AlIn xP yO z-InP interface

Abstract

Metal-insulator-semiconductor structures have been fabricated on n-type InP substrates using AlIn x P y O z layers as gate insulators. Formed AlIn x P y O z layers were found to have good properties as insulators. The 1 MHz and quasi-static capacitance-voltage measurements were performed to evaluate the density of interface states near the AlIn x P y O z -InP interface. From the Berglund analysis, the minimum density of interface states obtained was about 6 × 10 11 cm −2eV −1 at 0.30 eV below the conduction band edge of InP. The admittance connected with interface states was measured in the frequency range 0.02–5 kHz. The admittance data have been well explained by the tunneling model. For the interface states with (2 πτ) −1 ∼ 0.02–5 kHz, their distribution in the AlIn x P y O z layer was obtained, where τ is the time constant of the interface state. Such interface states were found to extend into the AlIn x P y O z layer up to about 25 Å in depth. The electron capture cross-sections were obtained for the interface states with (2 πτ) −1 ∼ 0.02–5 kHz located just at the AlIn x P y O z -InP interface. They are evaluated in the range 0.06–7.3 × 10 −16 cm 2 at about 0.27 eV below the conduction band edge of InP.