Accurate modeling and parameter extraction for 6H-SiC Schottky barrier diodes (SBDs) with nearly ideal breakdown voltage

Abstract

We have fabricated Ni Schottky rectifiers on 2.7/spl times/ 10/sup 16/ cm/sup -3/ n-type 6H-SiC epilayer using an effective edge termination based on an oxide ramp profile around the Schottky contact. Several anneals of the Schottky contacts were experimented. In particular the diodes annealed at 900/spl deg/C showed excellent reverse characteristics with a nearly ideal breakdown at about 800 V. Forward characteristics follow the thermionic emission theory with the ideality factor close to one at low biases. An accurate analytical model and complete parameter extraction of the forward characteristics of the Ni/6H-SiC Schottky barrier diodes (SBDs) for low and high-level current densities are presented. The model takes into account the high-level injection effects and the current dependence of the series resistance. Direct extraction of the SBD parameters is carried out. A very good agreement between the simulated forward curves using extracted parameters and measured data up to 500 A/cm/sup 2/ is obtained.