Low Temperature Fluorination of GaAs Surface

1)在低至300℃的CF4等离子体中对GaAs表面进行了氟化处理。2)用XPS分析了氟化膜的组成和成分。3)用氟化膜/n-GaAs制得的MIS二极管表现出相当好的电学特性，可与SiO_2/氢化-GaAs结构相媲美。4)试图用a-Si覆盖层作为防潮保护层，以减少氧气进入氟化物膜，但无济于事。5)通过使用新开发的具有三个独立电极的远程等离子体室来进行衬底表面的氢气清洁，可能覆盖有自然氧化物。6)即使在低于300℃的温度下，氢的离子物种也非常有效地去除衬底上的自然氧化物，7)膜中元素砷的去除还需要进一步的研究。

1) The GaAs surface was fluorinated at low temperatures as low as 300C in CF_4 plasma.2) The constitution and the composition of the fluoride films were analyzed by XPS. The film contained oxygen as well as elemental arsenic in the vicinity of the GaAs substrate.3) The MIS diodes fabricated with the fluoride film/n-GaAs showed fairly good electrical characteristics comparable to the SiO_2/hydrogenated-GaAs structure.4) An a-Si overlayer as a protection layer against moisture was tried in order to reduce oxygen introduction into the fluoride film, but in vain.5) Hydrogen cleaning of the substrate surface, possibly covered with native oxides, was done by using newly developed "remote plasma" chamber with three independent electrodes.6) Ionic species of hydrogen was very effective to remove native oxides on the substrate even below 300C, and furthermore introduced no process induced damages.7) Further study is needed for elimination of elemental arsenic in the film.