Ion beam assisted etching of GaAs by low energy focused ion beam

Abstract

We have been investigating the characteristics of the ion beam assisted etching (IBAE) of GaAs performed using a Ga low energy focused ion beam (FIB) and Cl2 gas. The etch yield increased monotonously with increasing the Cl2 flow rate and showed a tendency to saturate at a high Cl2 flow rate. At a flow rate of 7×1018 molecules/cm2 s and an ion current density of about 5 mA/cm2, etch yields of 18–52 atoms/ion were obtained for 0.2–15 keV Ga+ beams. The IBAE to physical sputter etching ratio was about 14 at 1 keV and above and became larger for lower energy. The etch yield of IBAE varied in proportion to the deposited energy at the surface. Residual chlorine was below the detection limit after IBAE by Auger electron spectroscopy. The radiation damage was estimated by photoluminescence (PL) measurements. After 600 °C annealing, full recovery of PL intensity was observed for IBAE at the energy of 0.2 keV.