The evolution of the sheet resistance of n-type epilayers irradiated with MeV H and 12C ions was studied. The results showed that both the implantation temperature (77 to 423K) and the ion-beam flux affected the process of electrical isolation in the case of irradiation with 12C ions. This behavior was consistent with the occurrence of appreciable dynamic annealing during MeV light-ion bombardment, and suggested a situation in which the centers responsible for electrical isolation were defect clusters or antisite-related defects. Dynamic annealing caused simple ion-beam generated Frenkel pairs to annihilate (or cluster) during irradiation at liquid-N temperatures and above. These beam-flux and irradiation-temperature effects were not observed during bombardment with lighter 1H ions; which produced very dilute collision cascades. A qualitative model was proposed in order to explain temperature and flux effects in the MeV light-ion bombardment regime which was used for electrical isolation.

Effect of Irradiation Temperature and Ion Flux on Electrical Isolation of GaN. S.O.Kucheyev, H.Boudinov, J.S.Williams, C.Jagadish, G.Li: Journal of Applied Physics, 2002, 91[7], 4117-20