The interdiffusion and solid-state reaction of low-energy copper ions implanted in silicon

At room temperature, single-crystal silicon was implanted with Cu+ ions at an energy of 80 keV using two doses of 5 × 1015 and 1 × 1017 Cu+ cm−2. The samples were heat treated by conventional thermal annealing at different temperatures: 200 °C, 230 °C, 350 °C, 450 °C and 500 °C. The interdiffusion and solid-state reactions between the as-implanted samples and the as-annealed samples were investigated by means of Rutherford backscattering spectrometry (RBS) and X-ray diffraction (XRD). After annealing at 230 °C, the XRD results of the samples (subject to two different doses) showed formation of Cu3Si. According to RBS, the interdiffusion between Cu and Si atoms after annealing was very insignificant. The reason may be that the formation of Cu3Si after annealing at 230 °C suppressed further interdiffusion between Si and Cu atoms.