Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The strong influence of dose rate and implantation temperature on the dose dependence of the shape of Ge channeling implantation profiles is demonstrated for the first time. Applying a focused ion beam (FIB) system allows the use of a very high (10¹⁸ cm^-2s^-1) and a very low (10¹⁰-10¹¹ cm^-2s^-1) dose rate. Implantations are performed at R.T. and at 250°C. At the high dose rate and R.T. the dose rate dependence of the profile shape is found to be most pronounced. Atomistic computer simulations using a relatively simple damage buildup model can explain the effects observed. It is shown that at R.T. defect relaxation processes can last up to 1 s, which is longer than assumed so far. The lifetime of implantation defects at 250°C is estimated to be in the order of 10s.