Hydrogen implantation into ZnO for n + -layer formation

Bulk ZnO crystals were implanted using 100 keV H + ions with doses 5 × 10 16 and 2 × 10 17 cm − 2 and subsequently annealed at 200 - 600 ° C to study the evolution of the implanted H by employing secondary ion mass spectrometry and scanning spreading resistance microscopy. It is shown that the heat treatment results in a decrease of H concentration in the implanted region, while no significant broadening of the H profiles is observed. This suggests that the implanted H is trapped in immobile complexes which dissociate during annealing with subsequent outdiffusion of H from the implanted region. The formation of a highly conductive n + -layer is observed in the implanted region, and the n + -layer is found to be stable up to 600 ° C . A correlation between electrical activity of H and presence of radiation damage is discussed.