June 14, 2012
Hydrogen Radicals ‘Heals’ Plasma-Damaged Semiconductor
Gallium nitride (GaN) is a highly promising material for a wide range of optical and high-power electronic devices, which can be fabricated by dry etching with plasmas. However, the plasma-induced defects and surface residues that remain after such processes tend to degrade the optical and electrical properties of the devices. A team of Japanese researchers has developed and tested a new way to "heal" such defects.
The team exposed plasma-damaged GaN to hydrogen (H) radicals at room temperature. After testing various doses of H radicals, the researchers evaluated the optical properties of the GaN. The intensity of light emitted when electrons near the edge of the valence shell in GaN absorbed and then re-emitted photons drastically decreased after chlorine plasma-beam etching. After treatment with the higher-level doses of H radicals, however, the photoluminescence was restored to almost the level of un-etched GaN.
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