Low Temperature Fluorination of GaAs Surface

1)采用CF_4等离子体在300 ℃低温下对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）用氟化物膜/n-GaAs结构制作的MIS二极管显示出与SiO_2/氢化GaAs结构相当的良好的电学特性。4）尝试用a-Si覆盖层作为防潮层以减少氧引入氟化物膜中，但是没有用5）通过使用新开发的具有三个独立电极的“远程等离子体”室来进行可能覆盖有自然氧化物的衬底表面的氢清洁6）氢的离子种类即使在低于30 ℃下也非常有效地去除衬底上的自然氧化物，并且没有引入工艺引起的损伤。7）需要进一步研究以消除膜中的元素砷。

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.