ANALYSIS OF THE IMPACT OF DISLOCATION DISTRIBUTION ON THE BREAKDOWN VOLTAGE OF GAAS-BASED POWER VARACTOR DIODES

A synchrotron x-ray topography analysis of the impact of the distribut ion of defects/dislocations on the electrical performance of GaAs powe r varactor diodes was carried out. Diodes fabricated on or near Liquid Encapsulated Czochralski cellular dislocation networks in the substra te, which are also known to be rich in As precipitates near these cell walls, were observed to have reduced breakdown voltages (V-BR). This is consistent with the possibility that the presence of space-charge c ylinders surrounding these dislocations gives rise to reduced VER if t hey thread a p-n junction; it is also in accord with the possibility t hat the As precipitates themselves can act as sites for local field en hancement, thus promoting premature avalanche breakdown. (C) 1996 Amer ican Institute of Physics.