Laser-controlled etching of chromium-doped 〈100〉 GaAs

The photocontrolled etching of 〈100〉 Cr:GaAs in HNO3 is examined in the wavelength region of 334–514 nm with an Ar ion laser. The etching rate decreases with increasing wavelength and correlates with the optical absorption coefficient in the GaAs. The etching process is found to be photochemically and not thermally controlled. Etch rates for the UV are 30(μ/s)/(MW/cm2) for laser intensities between 3 and 80 kW/cm2.