Electrical characteristics of Hg_(1-x)Cd_xTe (x= 0.1 to 0.8) grown on GaAs (100) by an inter diffused multilayer process

摘要

Hg1-xCd.vTe has been widely used for infrared detection in the long (8-12 fan), medium (3-5 jum) or short (1-2.5 jim) infrared spectral regions. Con-tinuous variation in the bandgap of the semicon-ductor was obtained by altering the Cd mole fraction of the alloy. The growth of Hg^Cd.vTe by metal/or-ganic vapour chemical deposition (MOCVD) on a substrate of GaAs has been performed typically at temperatures between 340 and 400 °C [1-5]. A buffer layer of CdTe has been used to contain misfit dislocations at the interface and prevent outdiffusion of Ga from the substrate [1-5]. However, the extent of indiffusion of Ga was shown to depend on the orientation of the substrate, even in the presence of a CdTe buffer layer. Korenstein et al. [6] have reported that the growth of Hg^Cd^Te on the (111)B orientation produced a higher Ga concen-tration by a factor of ~102 than for the (111)A orientation, while layers deposited on (10 0) yielded an intermediate level of Ga. These results were obtained by direct alloy growth of Hg^Cd^Te at a temperature of 360 °C [6].