Formation of InAs nanocrystals in Si by high-fluence ion implantation

We have studied the formation of InAs precipitates with dimensions of several nanometers in silicon by means of As (245 keV, 5 × 1016 cm−2) and In (350 keV, 4.5 × 1016 cm−2) implantation at 500 °C and subsequent annealing at 900 °C for 45 min. RBS, SIMS, TEM/TED, RS and PL techniques were used to characterize the implanted layers. The surface density of the precipitates has been found to be about 1.2 × 1011 cm−2. Most of the crystallites are from 3 nm to 6 nm large. A band at 1.3 μm has been registered in the low-temperature PL spectra of (As + In) implanted and annealed silicon crystals. The PL band position follows the quantum confinement model for InAs.