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

The temperature dependence of the breakdown voltage V-B, due to impact ioni zation 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 V-B with T is in excellent agreement with a simple model for the scatte ring of carriers by phonons with an effective energy of 42 meV. The impact ionization coefficients for the electrons and holes are nearly equal, and t heir geometric mean has the value 4 x 10(4) cm(-1) at the breakdown electri c fields, in good agreement with recent theoretical results for 300 K. (C) 2001 Elsevier Science Ltd. All rights reserved.