Theoretical evidence for random variation of series resistance of elementary diodes in inhomogeneous Schottky contacts

The current-voltage (I-V) characteristics of Schottky diodes measured at low temperature shows an abnormal behavior, which is attributed to the presence of spatial variation of barrier heights of Gaussian type at metal-semiconductor interface. The simulation studies assuming Gaussian distribution of barrier heights also show similar temperature dependence of diode parameters as observed in real Schottky contacts fabricated on various metal-semiconductor systems. The simulation studies performed so far on inhomogeneous Schottky contacts assumes constant series resistance (RS) to all elementary diodes because of the complexity in programming. We have simulated I-V characteristics of inhomogeneous Schottky diodes with Gaussian distribution of Barrier heights (BHs) assuming different RS for different elementary diodes in the distribution. It is found that the simulation performed using randomly varying RS having Gaussian distribution yields I-V characteristics similar to those obtained using constant RS with its value about which variation in RS is considered for all elementary diodes. The simulation results provide theoretical evidence about the occurrence of random fluctuation of RS of Gaussian type in elementary diodes in inhomogeneous Schottky contact.