Cl2 and HCl radical beam etching of GaAs and InP

Both the thermally activated and remote plasma activated etching reactions between Cl2 and HCl gases and GaAs and InP substrates are characterized. Though GaAs etches nearly three times faster in Cl2 with a remote plasma operating, the etch rate versus temperature behavior is similar to the plasma-off case. Significant etch rates of GaAs are observed for HCl remotely generated plasma even at room temperature (∼1500 Å/min). InP etching in HCl or Cl2 shows a weak temperature dependence for T>150 °C but changes rapidly below this temperature (EA∼55±15 kcal/mole).