Chromium concentrations, depth distributions, and diffusion coefficient in bulk and epitaxial GaAs and in Si

Abstract

Implantation of 200-keV chromium fluences from 4.5×1012 to 1.0×1015 cm−2 and SIMS profiling were used to measure the atom densities and depth distribution of Cr in bulk GaAs (Cr), in undoped liquid-phase epitaxial GaAs grown on a GaAs(Cr) substrate, and in Si. The Cr atom density in both GaAs(Cr) substrates was ∼1.6×1017 cm−3. The background-limited detection sensitivity of SIMS for Cr in GaAs was ⩽3×1015 cm−3. Chromium outdiffused into the epitaxial layer during growth at 800 °C. The diffusion coefficient for CR at 800 °C in GaAs was determined to be 6.7×10−12 cm2/sec. Channeling tails were observed for the Cr implanted in Si and in the undoped epitaxial GaAs, but not in the bulk GaAs(Cr). Ranges, range straggles, and other Pearson IV moments for the implanted Cr distributions are given.