Electrical isolation of p-type GaAsN epitaxial layers by ion irradiation

摘要

The evolution of sheet resistance (R_s) of p-type conductive GaAS(1-x)N_x epilayers (x=0.6%,1.4%,and 2.3%) exposed to MeV ~1H~+,~7Li~+,~(12)C~+,and ~(16)O~+ ions and the stability of the formed electrical isolation during post-irradiation annealing were investigated.Results show that the threshold dose (Dth) to convert a conductive layer to highly resistive one close-to-linearly depends on original free carrier concentration and inversely depends on the number of irradiation-generated atomic disglacements,and is independent of the nitrogen content in GaAsN layers.Increasing beam flux of ~(12)C~+ results in a lower D_(th) ,whereas lW beam flux does not affect it,showing the influence of collision cascade density.Results also show that irrespectively of the ion mass,the stability of electrical isolation formed in GaAsN is dependent on the ratio of the-concentration of irradiation-created carrier traps to D_(th).The electrical isolation can be preserved up to 550 deg C when the accumulated dose (D) is greater than 3.3 D_(th).