The interface states and series resistance effects on the forward and reverse bias I–V, C–V and G/ω-V characteristics of Al–TiW–Pd2Si/n-Si Schottky barrier diodes

Illumination intensity effects on the electrical characteristics of Al–TiW–Pd2Si/n-Si Schottky structures have been investigated in this study for the first time. The electrical parameters such as ideality factor (n), zero-bias-barrier height (ΦB0), series resistance (Rs), depletion layer width (WD) and dopping concentration (ND) of Al–TiW–Pd2Si/n-Si Schottky barrier diodes (SBDs) have been investigated by using the forward and reverse bias current–voltage (I–V), capacitance–voltage (C–V) and conductance–voltage (G/ω-V) measurements in dark and under illumination conditions at room temperature. The values of C and G/ω increase with increasing illumination intensity due to the illumination induced electron–hole pairs in the depletion region. The density of interface states (Nss) distribution profiles as a function of (Ec − Ess) was extracted from the forward I–V measurements by taking into account the bias dependence of the effective barrier heights (Φe) for device in dark and under various illumination intensities. The high values of Nss were responsible for the nonideal behavior of I–V, C–V and G/ω characteristics. The values of Rs obtained from Cheung and Nicollian methods decrease with increasing illumination intensity. The high values of n and Rs have been attributed to the particular distribution of Nss, surface preparation, inhomogeneity of interfacial layer and barrier height at metal/semiconductor (M/S) interface. As a result, the characteristics of SBD are affected not only in Nss but also in Rs, and these two parameters strongly influence the electrical parameters.