Optical emission characteristics of ablation plasma plumes during the laser-etching process of CdTe

Optical emission and surface compositional change during the laser-etching process of CdTe are reported. The etching rate increases in proportion to the laser energy density. However, the increase in etching rate is suppressed because ablation plasma plumes generated by the laser irradiation at the energy densities above 0.4 J/cm² shield the laser beam. The etching rate at the energy density of 1.0 J/cm² has been determined to be 91 nm/pulse. Also, 80-μm-deep and 55-μm-wide trenches have been formed with the laser-etching process.