Temperature dependence of the breakdown voltage for reverse-biased GaN p–n–n+ diodes

The temperature dependence of the breakdown voltage VB, due to impact ionization at high electric fields, for reverse-biased GaN p–n–n+ diodes has been measured at temperatures T between 98 and 248 K. The observed increase of VB with T is in excellent agreement with a simple model for the scattering of carriers by phonons with an effective energy of 42 meV. The impact ionization coefficients for the electrons and holes are nearly equal, and their geometric mean has the value 4×104 cm−1 at the breakdown electric fields, in good agreement with recent theoretical results for 300 K.