2 MEV ALUMINUM IMPLANTATION INTO SILICON - RADIATION-DAMAGE

Damage accumulation by 2 MeV Al implantation into Si at temperatures b etween 140 and 450 K and in a dose range of 8 X 10(12) - 1 X 10(17) Al /cm(2) is studied by optical reflectivity depth profiling. For a wide range of doses and target temperatures the dose dependence of damage i s compared to that observed after MeV implantation into Si for differe nt ion species (Si [1], N [2], Ni [3]). It is shown that the dose depe ndence of damage can be described by a common model. Investigations fo r a temperature of 350 K indicate that amorphous volumina produced at the depth of nuclear stopping power maximum act as sinks for point def ects in the profile wings. For temperatures of 400 K and above, damage profiles for doses of 5 X 10(16) Al/cm(2) and above show a reduction of damage at the depth of former damage maximum. This can be ascribed to a defect transformation into extended defects. Wavelength dependent measurements point to an accumulation of Al in the depth region of th ese defects. An impeding effect of implanted Al on the amorphization o f Si is evident from a comparison of critical doses with those of 2 Me V Si ions.