Dependency of barrier height and ideality factor on identically produced small Au/p-Si Schottky barrier diodes
Small high-quality Au/p-Si Schottky barrier diodes (SBDs) with extremely low reverse leakage current using wet lithography were produced. Their effective barrier heights (BHs) and ideality factors from current-voltage ( I- V) characteristics were measured by a conducting probe atomic force microscope (C-AFM). In spite of identical preparation of the diodes there was a diode-to-diode variation in ideality factor and barrier height parameters. By extrapolating the plots the built-in potential of the Au/p-Si contact was obtained as Vbi=0.5425 V and the barrier height value ( ΦB( C- V) ) was calculated to be ΦB( C- V) =0.7145 V for Au/p-Si for a typical 100 μm diode diameters. In the present work the nonlinear dependency of BH and ideality factor on the diode diameter studied fundamentally and an experimental relation for this new behavior is derived. It is found that for the diodes with diameters smaller than 100 μm the diode barrier height and ideality factor dependency to their diameters and correlation between the diode barrier height and its ideality factor are nonlinear, which is similar to the earlier reported different metal semiconductor diodes in the literature, these parameters for the here manufactured diodes with diameters more than 100 μm are also linear. Based on the very obvious sub-nanometer C-AFM produced pictures, the scientific evidence behind this controversy is also explained.