Abstrakt
The blistering efficiency in He-H-ions co-implanted and annealed InP has been found to peak and vanish in a narrow range of ion fluence ratio (?H/?He = 1.5?3.5) with a fixed He fluence of 2 ? 1016 He+/cm2. The blisters are formed at low fluence (?H/?He = 1.5), peaked in the middle (?H/?He = 2.5), and disappeared at the high fluence ratio (?H/?He = 3.5).
To get a fundamental understanding of blister formation in nanoscale, the defect profiles were studied by various experimental techniques combined with FEM and ab-initio simulations. Crosssection TEM images showed that at a low fluence ratio, He and H are stored in microcracks and bubbles whereas, at a high fluence ratio, the ions are trapped only inside bubbles.
These atomic processes that occur during and after co-implantation and annealing are presented together with detailed scenarios in an attempt to explain our results. Based on DFT simulations, the de-trapping of He atoms from the small clusters is energetically cheaper compared to the migration of He from the large clusters formed at high fluence.
Moreover, at a high fluence ratio, the presence of large clusters inhibits the He diffusion to the small clusters (precursor of blisters) by capturing migrating He atoms.