硅中热施主的电子结构

利用20—300K的Hall系数测量和6-300K的红外光吸收,研究了含氧P型CZ硅单晶经450℃不同时间热处理后所产生的热施主问题。Hall系数测量表明:经100hr热处理的样品存在两个施主能级:E₁=58meV,E₂=110meV。对不同热处理时间的样品,从低温红外光吸收则可看见由于热施主所引起的复杂吸收光谱。这些吸收峰的数目随着热处理时间的加长而增加和加强。利用类氢模型和有效质量理论拟会和计算,可以证明与氧有关的热施主很可能是双重电荷施主。这些双重施主有多种组态,它与450℃热处理的时间有关。 关键词：

THE ELECTRONIC STRUCTURE OF THERMAL DONOR IN ANNEALED SILICON

Using (20-300K) Hall coefficient measurement and (6-300K) IR optical absorption, thermal donor generated in P-CZ Si single crystal after heat treatment at 450℃ over a wide range of time has been studied. It is shown from Hall coefficient measurements that two donor levels in the specimen after 100 hrs. annealing are observed: E₁= 56 meV, E₂= 110 meV. Low temperature IR optical absorption of specimens after annealing of different duration shows complex structure arising from thermal donor. The intensity and number of the absorption peaks increase with increasing duration of annealing. The results obtained can be phenomenologically explained fairly well by the hydrogen-like effective mass approximation theroy assuming the occurence of different species of doubly charged donor. The oxygen-related thermal donor can also be possibly understood as doubly charged donor. The number of species of thermal donor is closely correlated to the duration of annealing.