Research On Preparation Of HgCdTe Films Crystal By Liquid Crystal Phase Epitaxy

At present, many reasons restrict the application and development of infrared detector seriously, such as the high cost, low growth efficiency, poor quality of HgCdTe films, foreign technology blockade and so on. Tellurium-rich horizontal graphite boat liquid phase epitaxy technology, for its low cost, simple process, mature technology, becomes the key to research on the growth of HgCdTe film in domestic and foreign. But how to get the better HgCdTe film on crystal structure integrity, that still has many problems to be solved, such as:(1) various surface macro defects, ripple formation mechanism and elimination thereof;(2)the distribution and characteristics of dislocation;(3)how to optimize the annealing conditions in order to reducing the dislocation density;(4) component uniformity of the material, etc. In this paper, combining with the research status at home and abroad, through the FTIR, X ray diffraction crystal rocking curve half peak width (FWHM), X ray topography physiognomy, metallographic microscope, chemical etch, SEM and other means, we study deeply on the structure and defects of HgCdTe film grown by graphite boat liquid phase epitaxy technology.1.Studying on how the crystal structure integrity of HgCdTe film, grown in liquid phase epitaxy, is effected by the sedimentary phase in cadmium zinc telluride substrate, twin, grain boundary, inclusions and other defects.The dislocations located around defects will extend divergent to film during epitaxial growth, which result in grain boundary and twinned crystal in film as well as impact seriously on the film structure integrity.2. Discuss the characteristics, causes, elimination methods of the HgCdTe film defects which include twinning and grain boundaries, black defects, crystallization, Te inclusions, scratch and surface ripples. At least, the quality of HgCdTe film has been improved.3.Reserch on the properties and dislocation of etch pits and studying different annealing conditions on the dislocation density.It reveals variable temperature cycle annealing can reduce effectively EPD, and release the stress in the material. It proves variable temperature cycle annealing can improve MCT film material crystal quality effectively. 4.Study in the component uniformity of HgCdTe films grown by LPE, We obtain the good uniformity.