Electrical evaluation of InP surface damage by reactive ion etching using mixture of ethane (C2H6) and hydrogen (H2)

The electrical properties of the (100) InP surface were studied based on the fabrication process of a buried heterostructure (BH) laser diode (LD). The current-voltage (I- V) and capacitance-voltage (C- V) characteristics were measured for Schottky barriers on the surface at each step of the process. The characteristic variation during the process showed the C2H6/H2-reactive ion etching (RIE) induced damage on the near-surface region: a layer resulting from phosphorus desorption, a low p-concentration layer due to hydrogen passivation, and deep donor defects with electrical drift phenomena. It was found that the damage layers were removed by annealing after the chemical etching which produced almost the same surface as that immediately before the BH regrowth.