Growth of InAsSb alloy layrs by compositional conversition and its application to mid-infrared sensing devices

InAsSb合金是一种很有前途的中红外器件材料。然而，缺乏与合金系统晶格匹配的衬底使得难以制造高性能器件。为了克服这一问题，本文采用“成分转换”的方法在现有的复合晶体衬底上制备了具有所需成分的InAsSb合金层。在该技术中，材料的熔点（Tf）对合金层的生长起着重要的作用，首先研究了低Tf晶体（InSb）在高Tf衬底（InAs）上的生长，明确了在相对较高的生长温度下可以获得层模式生长。在InAs衬底上生长InSb时，最佳温度范围为390 ~ 440 ℃。实验表明：高Tf合金组分向低Tf生长层的扩散很大，因此低Tf生长层的成分立即发生转变，在随后的时间内成分均匀化和晶格修复得到进展，最终合金成分与所用溶液达到平衡成分;因此，通过调节溶液的组成，可以实现具有所需组成的合金层;具有最高Tf的基底在该转化过程中是稳定的。在转化后的合金层上连续生长合金表明，生长合金的结晶质量得到了显著提高，从而开拓了InAsSb合金的器件应用前景。基于所获得的知识，可以制造中红外装置，使得在不久的将来所需的信息通信系统和/或空气污染监视系统取得进展。

InAsSb alloy is a promising material for mid-infrared devices. However the lack of a substrate lattice-matched to the alloy system makes it difficult to fabricate the higt performance devices. To overcome this problem, "compositional conversion" was applied to the formation of InAsSb alloy layrs with desired composition on a compound crystalline substrate available at present. In this technique, melting point (Tf) of the materials plays an important role to grow the alloy layr.At first, the growth of low Tf crystal (InSb) on a higt Tf substrate (InAs) was investigated and made it clear that layr-mode growth is obtained at relatively higt growth temperature. In the case of InSb growth on InAs substrates, the temperature range between 390C and 440C is preferable.The samples prepared were contacted to ternary solution saturated with alloy components, named "conversion process". The experiments made clear the following points : the diffusion of a high Tf alloy components into the low Tf grown layr is very high ; therefore the low Tf grown layr converts immediately in its composition ; homogenization in composition and lattice repairing advances in the following period ; the final alloy composition reaches to an equilibrium composition with the solution used ; therefore the alloy layrs with desired composition can be realized by adjusting the composition of the solution ; the substrate with the highest Tf is stable during this conversion process. Successive growth of alloy on the converted alloy layrs showed that the crystalline quality of grown alloy is drastically improved.Thus, the prospects for device application of InAsSb alloy was developed. Based on the knowledge obtained, the mid-infrared devices could be fabricated, making progress an information-communication system and/or an air pollution watching system demanded in near future.