Desorption in light-induced dry etching of GaAs with Cl2 around 120 nm

Quantum efficiency for etching corresponding to the removal of more than 50 Ga and As atoms per incident photon is observed in the spectral range from 115 to 130 nm, which exceeds the values at long wavelengths by four orders of magnitude. Replica of good quality and a submicron spatial resolution are produced. Desorption of reaction products (GaClx, AsClx) depends on the wavelength and the thickness of a layer of reaction products increases by one order of magnitude from 123 to 117 nm. XPS studies combined with sputtering indicate that also the composition varies with wavelength. The products can be desorbed by long wavelength irradiation.