Hydrogen Diffusion in Zinc Oxide Thin Films

Hydrogen diffusion in zinc oxide thin films was studied by secondary ion mass spectrometry (SIMS) measurements, investigating the spreading of implanted deuterium profiles by annealing. By effusion measurements of implanted rare gases He and Ne the microstructure of the material was characterized. While for material prepared by low pressure chemical vapour deposition an interconnected void structure and a predominant diffusion of molecular hydrogen was found, sputter-deposited ZnO films showed a more compact structure and long range diffusion of atomic hydrogen. Hydrogen diffusion energies of 1.8 – 2 eV, i.e. higher than reported in literature were found. The results are discussed in terms of a H diffusion model analogous to the model applied for hydrogen diffusion in hydrogenated amorphous and microcrystalline silicon.