Deep doping profiles in silicon created by MeV hydrogen implantation: Influence of implantation parameters

The impact of dose variations of protons implanted with energies in the MeV range on the concentration and depth distribution of hydrogen-related shallow donors in float zone and Czochralski silicon after annealing at 470°C is examined with spreading resistance probe measurements. For moderate proton doses up to 1014cm-2, the measured effective carrier distribution in float zone silicon correlates with the calculated distribution of the primary radiation damage caused by the penetrating protons. With increasing doses above 1014cm-2, however, the effective carrier distribution significantly deviates from the distribution of the primary defects. Furthermore, the shape of the induced profiles in float zone and Czochralski silicon differ considerably. The effective carrier concentration at the maximum of the induced donor profile exhibits a linear dependency on the implanted dose after annealing around 370°C, whereas this dependency becomes clearly sublinear when annealing at 470°C. A temperature dependent model using two donor species is proposed which accounts for the different dose dependencies at the different annealing temperatures.