Evolution of high-dose implanted hydrogen in ZnO

• Published in: Superlattices and microstructures 2005-10, Vol.38 (4), p.472-478
• Main Authors: Monakhov, E.V., Kuznetsov, A.Yu, Christensen, J.S., Maknys, K., Svensson, B.G.
• Format: Article
• Language: English
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2005.08.018

We have investigated evolution of implanted H in single crystalline ZnO in the temperature range from room temperature (RT) to 600  ∘C. H was implanted at RT with an energy of 100 keV and a dose of 2×10 17 cm −2. Secondary Ion Mass Spectrometry (SIMS) was used for the study of H distribution. The effect of the implanted H on electrical properties of ZnO as a function of depth was investigated by Scanning Spreading Resistance Microscopy (SSRM) and Scanning Capacitance Microscopy (SCM). After the implantation, the SIMS measurements reveal a H profile with a peak concentration of ∼10 22 cm −3 at a depth of 0.7 μm. An increased carrier concentration is observed by SSRM and SCM in the as-implanted sample in the H implanted region. After heat treatment for 2 h at 200  ∘C, no change in either H or carrier concentration profiles is detected. Annealing for 2 h at 400  ∘C leads to a decrease in the peak H concentration down to 2×10 21 cm −3. However, no diffusion-like broadening of the H profile is revealed. Heat treatment at 600  ∘C results in a further decrease of the H concentration to 2×10 20 cm −3 and, similarly to the 400  ∘C annealing, no broadening of the H profile is observed. This suggests that the implanted H is trapped in immobile complexes which dissociate during annealing with subsequent out-diffusion of H from the implanted region. The correlation between electrical activity of H and presence of radiation damage is discussed.