Swift heavy ion irradiation induced modification of electrical characteristics of Au/n-Si Schottky barrier diode

Abstract

Modification in the electrical transport properties of Au/n-Si(1 1 1) Schottky barrier diode (SBD) by swift heavy ion (SHI) irradiation has been investigated using in situ capacitance–voltage ( C– V) and current–voltage ( I–V) measurements at various irradiation fluences ranging from 1×10 12 to 1×10 13 ions cm −2. The variations in various parameters of the Schottky diode have been systematically studied as a function of fluence during irradiation. The ionized-donor concentration decreases with the increase in fluence, while the ideality factor, reverse saturation current and reverse leakage current increases with fluence. The change in these parameters is explained in the light of basic energy loss mechanisms of the SHI at the metal–semiconductor (MS) interface. The Schottky barrier height (SBH) decreases from a value of 0.83 eV for the unirradiated diode to 0.66 eV for the diode irradiated with a fluence of 1×10 12 ions cm −2. After this fluence the SBH remains almost constant up to a fluence of 1×10 13 ions cm −2. The reduction in SBH is caused by an increase in interface state density at the MS interface induced by SHI irradiation. The role of electronic energy loss in modification of interface states has been envisaged in relation to the immunity of SBH over a wide fluence range after an initial fluence of 1×10 12 ions cm −2.