Dynamics of laser stimulated etching of germanium by bromine

The dynamics of laser stimulated etching of Ge by Br2 have been studied by characterization of the desorbed products. The product time-of-flight distribution was measured with a quadrupole mass spectrometer, providing both product identification and velocity analysis. Transient reflectivity measurements were used to determine when the melt threshold for Ge was exceeded. At low Br2 pressure, etching at a rate of ∼0.1–0.2 Å per pulse was observed above the melt threshold. The principal product observed was GeBr2, whose translational energy distribution deviated slightly from Maxwell–Boltzmann: the observed distribution was relatively rich in high-energy species (i.e., hyperthermal).