Numerical study of electrical transport in inhomogeneous Schottky diodes

The Poisson equation together with the drift-diffusion equations have been used to simulate both forward and reverse I - V and C - V characteristics of inhomogeneous Schottky diodes. The barrier height distribution has been modeled by a single Gaussian. It is shown that the I - V and C - V curves and consequently extracted apparent Schottky diode parameters depend only slightly, if at all, on a lateral correlation between the single barrier patches in the structure for larger dimension of patches. The apparent barrier height of ordered structures differ only in several thousandths of volt from that of uncorrelated barrier patches. Very small differences were also found between the currents through the diodes with large inhomogeneities and nanosize inhomogeneities. The numerical results show that there is almost no dependence of the current on a pinch-off effect of electric potential. The diminishing of a drift part of the total current in the area of pinched-off potential is probably compensated by a greater diffusion current in the region. Consequently, very small and not unambiguous differences were found between the so called interacting and noninteracting diodes and this division is, according to the above results, questionable. (C) 1999 American Institute of Physics. [S0021-8979(99)02203-3].