Crystal Growth of InGaAsSb Compound Semiconductors for Infrared Devices

了解三元化合物半导体的晶体生长规律对制备InGaAsSb晶体作为红外材料具有重要意义。首先，研究了cz生长的InGaSb和GaAlSb，以及温差法和旋转Bridgman法生长的InGaAs的成分比、偏析和晶体质量的控制。对晶体生长模型进行了模拟，并与实验结果进行了比较。对于InGaAs在GaAs上的异质生长，采用横向过生长技术在SiN_x薄层上获得了低缺陷密度（10^4/cm^2）的晶体层。即使InGaAs中In的组成比从0.06提高到0.1，晶体质量也不会发生变化。其次，在不同组成比的多层生长中，研究了InAsSb在InAs上的光学性质；随着外延层数的增加，截止波长向较长波方向偏移。4个外延层的截止层为8mum，但吸收边不那么锋利。最后，在InGaAsSb/(100) InAs的研究中，在in - ga - as - sb源溶液中加入Gd组分可以提高生长外延层的电学性能。从SIMS测量中可以看出，溶液中的Gd与S组分发生反应，从而减少了S在外延层中的偏析。在300K和77K条件下，生长的InGaAsSb迁移率分别为3.0*10^4和8.2*10^4cm^2/Vs。300K时载流子密度为5.7*10^<15>，77K时载流子密度为4.0*10^<15>cm^<-3>。这些值相对优于InAs衬底的值。人们期望实验事实有助于红外材料的制造。

It is very important to understand the crystal growth of ternary compound semiconductors in order to grow InGaAsSb crystals used as infrared materials. First, the control of compositional ratio, segregation, and crystal quality were investigated in Cz-grown InGaSb and GaAlSb, and also in InGaAs grown by both the temperature difference method and the rotary Bridgman method. Further, the model of crystal growth was simulated compared with the experimental results. Concerning the hetero growth of InGaAs on GaAs, crystal layrs of low defect density (10^4/cm^2) was obtained on the SiN_x thin layr by the lateral over growth technique. The crystal quality was not changed even if the compositional ratio of In in InGaAs was increased from 0.06 to 0.1. Next, in the growth of multi-layrs with different compositional ratios, the optical properties of InAsSb on InAs were studied ; The cutoff wavelength shifted to the longer wavelength with the number of epi-layrs. The cutoff one of 4 epi-layrs was 8mum though the absorption edge was not so sharp. Finally, in study of InGaAsSb/(100) InAs, the addition of Gd component into the In-Ga-As-Sb source solution made the electrical properties of grown epi-layrs raise. From the SIMS measurement, it was understood that Gd in the solution reacted with S component and as a result the segregation of S into the epi-layr was reduced. The mobility of grown InGaAsSb was 3.0*10^4 and 8.2*10^4cm^2/Vs at 300K and 77K,respectively. The carrier density was 5.7*10^<15> at 300K and 4.0*10^<15>cm^<-3> at 77K.These values were relatively superior to those of the InAs substrate. Experimental facts were expected to contribute to the fabrication of infrared materials.