Electrical isolation of ZnO by ion bombardment

The evolution of sheet resistance of n-type single-crystal wurtzite ZnO epilayers exposed to bombardment with MeV ${}^{\mathrm{1}}\mathrm{H},$ ${}^{\mathrm{7}}\mathrm{Li},$ ${}^{\mathrm{16}}\mathrm{O},$ and ${}^{\mathrm{28}}\mathrm{Si}$ ions at room temperature is studied in situ. We demonstrate that sheet resistance of ZnO can be increased by about 7 orders of magnitude as a result of ion irradiation. Due to extremely efficient dynamic annealing in ZnO, the ion doses needed for isolation of this material are about 2 orders of magnitude larger than corresponding doses in the case of another wide-bandgap semiconductor, GaN. Results also show that the ion doses necessary for electrical isolation close-to-inversely depend on the number of ion-beam-generated atomic displacements. However, in all the cases studied, defect-induced electrical isolation of ZnO is unstable to rapid thermal annealing at temperatures above ∼300 °C.