Atomic layer etching of (100)/(111) GaAs with chlorine and low angle forward reflected Ne neutral beam

Characteristics of atomic layer etching of (100) GaAs and (111) GaAs have been investigated using Ne neutral beam and Cl₂ gas. By using a Ne neutral beam dose and a Cl₂ gas pressure higher than critical values of 3.03 × 10¹⁶ atoms/cm²·cycle and 0.4 mTorr, respectively, steady state etch rates of 1.41 Å/cycle for (100) GaAs and 1.63 Å/cycle for (111) GaAs which correspond to the etch rate of one atomic layer/cycle could be obtained. At the monolayer etching condition, the roughness of the GaAs surface was remaining similar to that of the unetched GaAs surface. In addition, the GaAs etched by the atomic layer etching showed the surface composition similar to that before the etching while the GaAs etched by a conventional reactive ion etching such as an inductively coupled plasma etching showed significant change in the surface composition.