Induced Defects in GaAs Etched by Low Energy Ions in Electron Beam Excited Plasma (EBEP) System

Abstract

Ion beam etching (IBE) of GaAs with a source gas of Cl 2 or Ar was carried out at a low energy ranging from 5 to 130 eV by using an electron-beam-excited-plasma system, and residual defect centers were investigated by means of deep-level transient spectroscopy (DLTS). Foul kinds of defect centers labeled L1 L2, L3, L5 with activation energies of 0.31, 0.45, 0.58, 0.48 eV, respectively, were resolved. Three of them were associated with damages induced by IBE and it was found that they have different thresholds for their generation, i.e., 60, 40 and 20 eV for L1, L2 and L3, respectively. It is necessary to reduce ion energy to less than 20 eV for perfect damage-free IBE of GaAs.