A new recombination model for device simulation including tunneling

Abstract

A recombination model for device simulation that includes both trap-assisted tunneling (under forward and reverse bias) and band-to-band tunneling (Zener tunneling) is presented. The model is formulated in terms of analytical functions of local variables, which makes it easy to implement in a numerical device simulator. The trap-assisted tunneling effect is described by an expression that for weak electric fields reduces to the conventional Shockley-Read-Hall (SRH) expression for recombination via traps. Compared to the conventional SRH expression, the model has one extra physical parameter, the effective mass m*. For m*=0.25 m/sub 0/ the model correctly describes the experimental observations associated with tunneling. The band-to-band tunneling contribution is found to be important at room temperature for electric fields larger than 7*10/sup 5/ V/cm. For dopant concentrations above 5*10/sup 17/ cm/sup -3/ or, equivalently, for breakdown voltages below approximately 5 V, the reverse characteristics are dominated by band-to-band tunneling.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>