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一、引言 由于微波、激光、发光器件发展,促进了砷化镓衬底材料发展,而液封直拉法具有成品率高,规模大等优点使它日益成为拉制砷化镓的一种重要方法。 但是如文献所指出的那样,液封法由于B_2O_3液封剂存在,加之它固有的表面张力特性,其润湿角大于13°,自然趋于不平衡,等径控制较难实现。加上砷化镓单晶由于砷的存在,拉晶时不可避免有所逸出,对人体健康妨碍较大,因此如何用计算机实现自动控制,已是一个迫切任务。 我所采用上海玩具九厂产品SJX-107改进型的测量电视,成功地应用数字滤波方法介决了光环边缘的气泡干扰,较为准确地测
I. INTRODUCTION Due to the development of microwaves, lasers and light-emitting devices, the development of gallium arsenide substrate materials has been promoted. However, the liquid-sealed direct pull method has the advantages of high yield and large scale making it an increasingly important material for drawing gallium arsenide method. However, as pointed out in the literature, the liquid seal method due to the existence of B 2 O 3 liquid sealant, combined with its inherent surface tension characteristics, the wetting angle greater than 13 °, naturally tends to be unbalanced, equal control is more difficult to achieve. With gallium arsenide single crystal due to the presence of arsenic, crystal pulling inevitably have escaped, the greater the health hazards, so how to use computer automation is an urgent task. I used the Shanghai Jiujiu Changjiu products SJX-107 improved measurement of the TV, the successful application of digital filtering method to solve the bubble edge of the ring interference, a more accurate measurement