分子云外延Hg1-yCdySe/InAs/Si(211)红外探测器材料

High performance and large scale focal plane array need to be prepared under the condition of infrared technology development and application. There are large lattice mismatch and etch pit density(EPD) for Hg1-xCdxTe material at the range of long wavelength, which is degraded the performance of infrared focal plane array. This project proposed "Molecular Cloud Epitaxy(MCE)" technology which is combined with Liquid Phase Epitaxy (LPE), Hot Wall Epitaxy (HWE) and Isothermal Vapor Phase Epitaxy(ISOVPE), to prepare Hg1-xCdxSe films on InAs/Si(211) composite substrates. High quality, large scale, cheap long-wavelength infrared focal plane array could be obtained due to their comparatively low lattice mismatch and etch pit density between Hg1-xCdxSe films and InAs/Si(211) composite substrates. High quality Hg1-xCdxSe thin films and InAs/Si(211) substrates with As activation could be obtained through the improvement of MCE system, optimizing the preparation of quartz mold and growth conditions. The structure and properties of thin films could be characterized by XRD, FITR, SEM, Stylus profiler and Hall measurements. Furthmore, Hg1-xCdxSe films could be used to fabricate the infrared focal plane array. The results of this project obtained will provide the advanced material foundation for the development of long-wavelength of high performance infrared detectors.

红外长波技术发展及应用需要制备高性能大面积焦平面列阵。Hg1-xCdxTe材料在长波波段与衬底晶格失配度较大、位错密度较高，严重影响红外焦平面列阵性能。本项目提出采用结合液相外延（LPE）、热壁外延（HWE）、等温汽相沉积（ISOVPE）技术特点的"分子云外延（MCE）"，在InAs/Si(211)复合衬底表面制备Hg1-xCdxSe薄膜，Hg1-xCdxSe材料在长波波段与复合衬底晶格失配度较小、位错密度较低，进而可获得高质量、大面积、廉价长波红外焦平面列阵。通过完善分子云外延系统、优化制备石英模具及生长工艺条件，获得高质量As活化InAs/Si(211)复合衬底及组分均匀的Hg1-xCdxSe薄膜。通过XRD、FITR、SEM、台阶仪和Hall等对薄膜结构和性能进行表征；同时，将HgCdSe材料用于试制红外探测器焦平面列阵。项目研究结果为长波波段高性能红外探测器件研制奠定新的材料基础。

本项目采用分子云外延（Molecular Cloud Epitaxy，MCE）技术，在InAs/Si(211)复合衬底表面制备Hg1-xCdxSe薄膜。Hg1-xCdxSe材料在长波波段与复合衬底晶格失配度较小、位错密度较低，进而可获得高质量、大面积、廉价长波红外焦平面列阵。通过完善分子云外延系统、优化制备石英模具及生长工艺条件，获得高质量As活化InAs/Si(211)复合衬底及组分均匀的Hg1-xCdxSe薄膜。通过XRD、FITR、SEM、AFM、台阶仪和Hall等对薄膜结构和性能进行表征。项目获得以下结果：1. 通过加热去氢、As活化、低温生长缓冲层和增加后退火工艺等，在Si(211)衬底表面制备了InAs、CdSe和HgCdSe薄膜。测试结果表明获得了(111)择优取向、表面均匀平整、组分均匀的HgCdSe/InAs/Si(211)复合衬底材料；2. 在Si(211)衬底表面成功制备了InAs薄膜，薄膜具有闪锌矿结构并沿(111)方向择优生长。生长温度为400℃时薄膜的晶粒尺寸最大为73.4nm，载流子浓度达到10E22cm-3，霍尔迁移率数值约为10E2cm2/(V•s)，400℃生长的薄膜平均表面粗糙度Ra为48.37nm；3. 通过改变生长温度、蒸发源温、Se和Cd配比等生长参数，优化CdSe薄膜制备工艺。FTIR测试结果表明，在频率432-434、610-611和758-763cm-1存在典型的Cd-O弯曲和Cd-Se伸缩振动模式的峰。CdSe薄膜体电阻率为2.608Ohm∙cm，载流子浓度约为1.2E16cm-3，霍尔迁移率为2.0E2cm2∙v-1∙s-1；4. 通过使用Material Studio计算软件，采用GGA+PBE、PBESOL、RPBE等算法，截断能设置为450eV，k网格设置为2×2×2，赝势选择为Norm conserving，对Hg1-xCdxSe材料电子结构、光学性质、声学性质等进行系统完整的计算；采用Hubbard U方法，计算结果与实验值能够较好匹配。项目研究结果为进一步研究长波波段高性能红外探测器件奠定材料和理论基础。