Modified transmission line model and its application to aluminum ohmic contacts with n-type GaN

A modified transmission line model (MTLM) of ohmic contact measurement is presented. This model preserves the simplicity of the circular transmission line model but eliminates the shortcoming of the possibility of obtaining misleading results. This model was applied to n-type GaN ohmic contacts and results similar to those obtained by Hall measurement were obtained. The ohmic contact pattern used in MTLM method occasionally exists during the fabrication of several devices. In such cases, the method can be used to determine the device processing quality without the need for any other test pattern.