Crystallinity and resistivity of ZnO thin films with indium implantation and postannealing

Ion implantation experiments of indium (In) into sputter-deposited undoped ZnO films were carried out to control the resistivity for n + - Zn O layers of electronic device. Improvement of ZnO crystallinity after the ion implantation was revealed by x-ray diffraction patterns including a shift of lattice parameter, enhancement of peak intensity, and a decrease in full width at half maximum in 2 θ . In-implanted ZnO crystallinity was greatly improved compared to results of the Ga and Al-implanted ZnO experiments. The resistivity of 1 × 10 16 ions ∕ cm 2 implanted ZnO film was decreased with over 11 orders of magnitude to 5.1 × 10 − 2 Ω cm with postimplantation annealing at 400 ° C . The ratio of resistivity between unimplanted ZnO and In-implanted one at 1 × 10 15 ions ∕ cm 2 was seven orders of magnitude after annealing at 300 ° C . The In-implanted ZnO would be suitable for fabricating source and drain regions of ZnO thin film transistors.