GaAS/Si(100)异质外延4°偏角衬底对外延层结晶质量的提高(英文)

Crystalline quality improvement of GaAs/Si(100) heterostructures by using 4° misoriented substrates

用低压金属有机物化学汽相沉积法(MOCVD)在Si(100)无偏角和Si(100)4°偏角衬底上外延生长GaAs层。异质外延采用两步生长法,并分别优化了两种衬底上的非晶低温缓冲层的生长条件。用X射线双晶衍射(XRD)和透射电子显微镜(TEM)对两种衬底上的GaAs外延层进行了结构表征,其中Si(100)4°偏角衬底上1.8μm厚GaAs的(004)面XRD衍射半高全宽338 arcsec,同比在无偏角衬底上的半高全宽为494arcsec,TEM图片显示4°偏角衬底上外延层中的位错密度大大降低。

GaAs epilayers were grown on exactly （100） -oriented Si and 4° misoriented （100） Si substrates by low - pressure metalorganic chemical vapor deposition （ LP - MOCVD）. Two - step method was used to the heteroepitaxial growth and the initial amorphous GaAs buffer layers were optimized, respectively. X -ray diffraction （XRD） and transmission electron microscopy （TEM） were employed to characterize the quality of GaAs epilayers. The full width at half maximum （FWHM） value of XRD （400） ω scan is 340arcsec for 1. 8μm GaAs epilayer on 4° misoriented （100） Si, compared to 494arcsec for 1.8μm GaAs epilayers on exactly （100） -oriented Si. The images of TEM shows the dramatical reduction of dislocations in GaAs epilayers on 4°misoriented （100） Si substrates.