The behavior of intrinsic materials (i-GaN and i-AlN) at high fields and room temperature, using small gap lateral test devices in vacuum ambient, is analyzed. Unprecedented hold-off fields of more than 375 kV/cm were obtained for intrinsic nitride layers grown on sapphire. The superior high field performance of intrinsic nitride materials indicate a great potential of nitride semiconductors for the next generation high power/high voltage/high frequency/high temperature electronic devices. (C) 1995 American Institute of Physics.