Electrical properties of InPxOy -InP metal-insulator-semiconductor structures

The electrical properties of n-type InP metal-insulator-semiconductor (MIS) structures have been investigated. As gate insulators, InPxOy layers are formed by a new method. In the method, a Px′Oy′ layer is deposited on InP by evaporation of P2O5 powder. The reaction between the Px′Oy′ layer and InP substrate yields an InPxOy layer. The InPxOy layers 500–1450 Å thick exhibit high resistivities ρ and low dielectric dissipations D, i.e., ρ≊2×1015 Ω cm and D≤0.01 in the frequency range 0.02–100 kHz at room temperature. The hysteresis in the capacitance-voltage curves of a typical InP MIS structure is found to be less than 0.6 V and an ion-drift type. The interfacial properties of InP MIS structures are shown to be well explained by the statistical model in the conductance method. A typical value of the minimum surface state density is evaluated as 3.3×1011 cm−2 eV−1 at about 0.26 eV below the conduction-band edge. The distribution of the electron capture cross sections σ of surface states is also obtained, e.g., σ=1.6×10−16 cm2 at 0.4 eV below the conduction-band edge.