Damage Recovery and Dopant Diffusion in Si and Sn Ion Implanted β-Ga2O3

Abstract

The commonly used n-type dopants, Si and Sn, were implanted into bulk (−201) β-Ga2O3 over a 2 order of magnitude dose range and annealed at temperatures from 1000–1150°C. The original lattice parameters were restored by annealing at 1150°C for the highest dose Si implants, while only partial recovery was observed in Sn implanted samples. The Sn implanted samples had overall lower lattice parameters compared to the Si implanted samples, indicating that Sn generates tensile strain in the Ga2O3 lattice. The rocking curve FWHM was observed to increase with the annealing process, indicating that the annealing process does not improve the crystal quality. Transmission electron microscopy showed removal of the end-of-range lattice damage after 1150°C anneals of the heaviest implanted species, Sn. Cathodoluminescence at 5K showed recovery of intensity of the common UV band around 3.2 eV after annealing. Secondary Ion Mass Spectrometry profiling showed the presence of concentration-dependent diffusion of both Si and Sn, with values for diffusivity at 1150°C of 9.5 × 10−13 cm.s−1 for Si and 1.7 × 10−13 cm.s−1 for Sn obtained by fitting through the FLOOPS simulation package.