Changes in the sheet resistance of n-type and p-type conductive layers during proton irradiation, and the stability of the resultant insulation during post-irradiation annealing, were investigated. It was found that the threshold dose which was required in order to convert the conductive layer into a highly resistive one was different for n-type and p-type samples having similar initial free carrier concentrations. From the results, it was deduced that the antisite defects and/or related defect complexes which formed via replacement collisions were the carrier trapping centres, where InP was responsible for electron trapping and PIn for hole trapping.

Electrical Isolation of n-Type and p-Type InP Layers by Proton Bombardment. H.Boudinov, H.H.Tan, C.Jagadish: Journal of Applied Physics, 2001, 89[10], 5343-7