IN-SITU CHARACTERIZATION TECHNIQUES FOR MONITORING AND CONTROL OF VPE GROWTH OF HG1-XCDXTE

In situ diagnostic techniques are broadly divided into two categories, those involving an electron probe or reflected beam and those relying just on photon beams. The former, such as RHEED, XPS, AES and UPS, can be used in MBE monitoring but are not suitable for the high-pressure environment of MOVPE. Optical diagnostic techniques such as ellipsometry, laser reflectometry, quasielectric light scattering, reflection difference spectroscopy (RDS) and infrared reflection-absorption spectroscopy (IRRAS) can be used as an in situ monitor in both UHV and high-pressure growth chambers. These are compared with the electron beam techniques and some analogues are established in terms of the properties of the growing films. The in situ monitoring of MCT growth is helping to improve layer quality and reproducibility. Some specific examples are discussed, including the potential for in situ feedback control.