Computer analysis of dc field and current-density profiles of DAR IMPATT diode

A computer study is carried out on the dc field and current-density profiles of an Si n(+)-p-nu-n-p(+) double avalanche region (DAR) IMPATT. It is found that with increasing current density, the uniform electric field in the central drift region remains almost unaffected owing to a cancellation of mobile space charge for the case of a symmetrically doped structure. What is more, the avalanche and drift-zone widths and the RF conversion efficiency remain almost unaltered. A small space-charge effect is seen in the case of asymmetric doping. A DAR device suitable for operation in the range 40-50 GHz is chosen, with W = 1.3 microns.