プラズマイオンと紫外光線のシナジー効果によるワイドギャップ半導体エッチングダメージの振舞い

Damage characteristics of wide gap semiconductors (n-GaN and TiO2) etched or exposed by low
temperature plasmas have been studied. Morphologies of n-GaN surfaces etched by CCP He plasmas
seem to be similar to that of the as-grown, regardless of gas pressure and etch time, while
morphologies of TiO2 surfaces etched at high gas pressure (7~13 Pa) become rough when the etch
time lengthens. This difference between the two semiconductors would be explained by synergy
effect of He plasmas ions and UV lights (which corresponds to TiO2 band gap energy) emitted. In
contrast, DBD air plasma at 1 kPa and JET He plasma do not cause damage to TiO2: photo-catalytic
properties (hydrophilicities) of TiO2 are more enhanced by these two plasmas.