Theoretical accuracy of using Boltzmann and ionized impurity approximations in the analyses of recombination current at interface traps in metal-oxide-silicon structures

In order to provide high computation speed, the Boltzmann distribution and fully ionized impurity (BI) approximations have been used to analyze experimental recombination current data to extract interface properties of metal-oxide-semiconductor (MOS) structures. The accuracy of the BI approximation is theoretically estimated in this paper by computing its deviation from the exact Fermi distribution and de-ionizable-impurity theory. Five device and material parameters of the MOS transistor structures are varied: substrate dopant-impurity concentration, gate oxide thickness, forward source and drain junction bias, interface-trap energy level, and transistor temperature. The results show that the BI approximation gives less than 5% deviation over the practical ranges of the five parameters. (c) 2006 American Institute of Physics.