Static current-voltage characteristics of Au/CaF2/n-Si(111) MIS tunneling structures

Using molecular-beam epitaxy, Au/CaF2/n-Si(111) structures were fabricated that exhibit lower currents at a given fluoride film thickness (1.5-2 nm) than those of all similar structures studied. At a positive voltage at the metal, the current is in agreement with that calculated within the model with conservation of the transverse component of the wave vector during tunneling transport. Relative contributions of electron and hole components were analyzed for forward and reverse biases. The effect of the nonuniform distribution of the insulator thickness over the area on measured currents was estimated. The thin CaF2 layers that were grown are potentially applicable as barrier layers in various devices of functional electronics.