IN-SITU CHARACTERIZATION TECHNIQUES FOR MONITORING AND CONTROL OF VPEGROWTH 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, ca n be used in MBE monitoring but are not suitable for the high-pressure environment of MOVPE. Optical diagnostic techniques such as ellipsome try, laser reflectometry, quasielectric light scattering, reflection d ifference spectroscopy (RDS) and infrared reflection-absorption spectr oscopy (IRRAS) can be used as an in situ monitor in both UHV and high- pressure growth chambers. These are compared with the electron beam te chniques 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.