MOCVD法生长HgCdTe/CdTe/GaAs多层异质结材料工艺和性能研究

Study on the Preparation of the Multilayers Hetero-structures of HgCdTe/CdTe/GaAs Grown by MOCVD

本文简述MOCVD法生长HgCdTe晶膜的优点。采用变通的多层互扩散工艺生长了HgCdTe/GaAs外延片。研究了生长HgCdTe生长速率与衬底温度的关系,DETe和DMCd源分压对生长速率的影响,Hg_(1-x)Cd_xTe中x值与汞源温度的关系,当汞源温度固定时,Hg_(1-x)Cd_xTe中x值与气体流速V的关系。并采用多种方法分析HgCdTe外延片的表面形貌,结晶性,界面和缺陷,Te、Cd、Hg、Ga、As的截面分布,组份和其均匀性,光电性能等。测得HgCdTe和缓冲层CdTe的FWHM为450弧度秒,界面平坦、清晰,过度层约0.12μm。生长x值为0.1～0.8mol,均匀性△X=0.008。典型样品的性能,在77K电子浓度为1.4×10^(16)cm^(-3),迁移率为7.4×10~4cm^2/v·s,透射率为42％。

The n-type HgCdTe/CdTe/GaAs epitaxial layers were prepared by modified process of interdiffussion of multi-layers. The relationships of growth rate and temprature, x value and the temperature of Hg source, and x value and the ratio of DMCd/ DETe have been studied. The surface morphology, crystallinity, interface, defects, x value, compositional uniformity and Photoelectricity of the MOCVD epitaxial layers were analyzed. The HgCdTe in the area of I5×15mm^2 has the good morphologies and monocrystalline, Their interfaces are smooth. The FWHM of epitaxial CdTe and HgCdTe are 450 arc. sec., the diffussions of Ga and As are little or not found in the width of 0.12 μm, but there are microdefects in some small regions. The ranges of x value are 0.1-0.8, uniformity △x is about 0.008. The electron concentration, mobility and transmissivity of the typical sample is 1.4×10^(16)cm^(-3), 7.4×l0~4cm^2/v.s and 42% at 77k, respectively.