The effect of series resistance on the relationship between barrier heights and ideality factors of inhomogeneous Schottky barrier diodes

We have studied Cd/n-Si (33 dots) Schottky barrier diodes (SBDs). Si surfaces have been prepared by the usual chemical etching. and the evaporation of metal has been carried out in a conventional vacuum system. The effective Schottky barrier heights (SBHs) and ideality factors obtained from the current-voltage (I-V) characteristics differ from diode to diode although the samples were identically prepared. The SBH for the Cd/n-Si diodes ranged from 0.605 eV to 0.701 eV. and ideality factor n from 1.213 to 1.913. The reason for that the experimental data differ from diode to diode has been analyzed by applying thermionic emission theory (TET) of inhomogeneous Schottky contacts together with standard TET and thus the effect of series resistance on the relationship between barrier heights and ideality factors of the inhomogeneous SBDs has clearly been shown. A laterally homogeneous SBH value of approximately 0.770eV for Cd/n-Si SDs has been obtained by the barrier inhomogeneity model.