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在 n 型砷化镓外延层的汽相生长中,硫是一个常用的掺杂剂。最简单的方法是用硫化氢作为汽相掺杂剂。用氢稀释的这种气体可以购买到,并用可变泄孔送进淀积系统中。但是,由于泄漏速度的不可逆的变化,要得到恰当限量的以及可重复的掺杂剂浓度是困难的。实验已表明,在真空系统中常用的可变泄漏(Varian,Leybold)只能校准到一个数量级之内。其他方法例如用精密计量阀和转子法量计逐级稀释掺杂气体,也需大量的设备和长时间的校准。参考资料中关于气相中硫化氢浓度和外延膜中的施主浓度之间的关系方面的数据。存在着大量矛盾,多半是由这些问题所造成。
In the vapor phase growth of n-type gallium arsenide epitaxial layers, sulfur is a common dopant. The simplest method is to use hydrogen sulfide as a vapor phase dopant. This gas, diluted with hydrogen, is commercially available and fed into the deposition system with variable venting. However, due to the irreversible change in leak rate, it is difficult to get the proper limit and repeatable dopant concentration. Experiments have shown that the variable leak (Varian, Leybold) commonly used in vacuum systems can only be calibrated to an order of magnitude. Other methods, such as diluting the doping gas stepwise with precision metering valves and rotor gauges, require extensive equipment and long calibration. Reference data regarding the relationship between the concentration of hydrogen sulfide in the gas phase and the donor concentration in the epitaxial film. There are a large number of contradictions, mostly caused by these problems.