采用界面失配阵列技术在GaAs衬底上生长GaSb

Growth of GaSb on GaAs substrate by Interfacial Misfit arrays

采用界面失配阵列(Interfacial Misfit arrays,IMF)技术深入研究了在GaAs衬底上外延生长GaSb,研究了生长温度、Sb:Ga等效原子通量比、AlSb过渡层厚度和GaSb外延层厚度对材料结构质量的影响。其中,生长温度、AlSb过渡层厚度是影响GaSb材料结构质量的重要因素,通过高分辨率X射线衍射(HRXRD)研究,HRXRD测量材料的衍射峰半高全宽(FWHM)值对这两个参数的变化非常敏感,而Sb:Ga等效原子通量比(Effective atomic flux ratio),在富Sb条件下,材料结构质量受其变化影响有限,GaSb衍射峰FWHM值随其变化轻微,但是GaSb材料层结构质量随其厚度增加而提高。优化的条件为GaSb材料生长温度约为515℃,AlSb过渡层厚度为5 nm。制备10 nm厚的GaSb外延层,经HRXRD测试,其衍射峰FWHM值仅为约15 arcsec,与商用GaSb衬底的衍射峰FWHM值相当。生长于其上的量子霍尔器件,在1.8 K及无电场偏压测量条件下,电子迁移率高达1.5×10^(5)cm^(2)/Vs,达到了GaSb衬底上器件性能水平。

The epitaxial growth of GaSb on GaAs substrate was studied by using interface mismatch arrays(IMF).The effects of growth temperature,Sb:Ga effective atomic flux ratio,thickness of AlSb transition layer and GaSb epitaxial layer on the structural quality of the material were studied.High Resolution X-ray Diffraction(HRXRD)study shows that the FWHM of the diffraction peak measured by HRXRD was very sensitive to the changes of above parameters,while the effective atomic flux ratio(EFF)of Sb:Ga was the most important factor.The FWHM value of GaSb diffraction peak changes slightly with the increase of thickness,but the structural quality of GaSb layer improves with the increase of thickness.The results show that the optimum growth temperature of GaSb is 515℃,the optimum thickness of AlSb transition layer is 5 nm.The 10 nm thick GaSb epitaxial layer was prepared and characterized specifically.The results show that the FWHM value of the diffraction peak is only about 15 arcsec,which is equivalent to that of commercial GaSb substrate.The electron mobility of the quantum Hall device is as high as 1.5×10^(5) cm^(2)/Vs at 1.8 K under zero bias,which attains to the level of device performance on GaSb substrate.