PLASMA-INDUCED DAMAGE BEHAVIOR IN GAAS BY PHOTOREFLECTANCE SPECTROSCOPY

Photoreflectance spectroscopy (PR) is applied to in situ, noninvasive determination of plasma-induced damage in GaAs for the first time. PR can evaluate damage such as nonradiative recombination centers and compensation centers in a near-surface layer. A new source of damage is revealed: short-term introduction followed by reduction of nonradiative recombination centers. This phenomenon cannot be detected by photoluminescence spectroscopy, a conventional noninvasive method. Comparing PR to the C- V method, we show that PR can be used as a highly sensitive probe for damage confined within the near-surface layer. This discovery will be helpful in developing methods that can be used for real-time, noninvasive detection of process-induced damage occurring during device processing.