An extraction method for areal forward current/voltage characteristics of circular GaN p(+)n diodes

Anode-size-independent forward current-density/voltage (V) characteristics of circular GaN p(+)n diodes were extracted (in the V range of 2.7-3.0 V) from measured ones by an estimation technique of the effective anode radius, followed by the least-squares fitting technique of peripheral-to-area ratio analysis. It was found that the extracted diffusion current of diodes with a higher p-type doping level is lower than that of diodes with a lower one and that both currents have an ideality factor of unity. Since these findings agree with the diffusion theory, the demonstrated method should be useful for theoretical analysis of GaN p(+)n diodes.