STUDY OF GE MOVEMENT DURING THERMAL-REACTIONS BETWEEN PT AND GESI SI HETEROSTRUCTURES/

Germanium movement in the thermal reaction between Pt and the Ge0.15Si 0.85/Si heterostructure was studied by Auger electron spectroscopy. Th e compounds formed were identified by x-ray diffraction after various anneals from 300 to 760-degrees-C. Pt2Ge and Pt2Si formed at low annea ling temperatures. At higher temperatures, Pt (GexSi1-x) formed. Two t ypes of Ge segregation were observed. Ge was rich at the surface and t he PtGeSi/GeSi interface. Some Ge was pushed inward during thermal rea ction at all of the above conditions. This procedure was enhanced by h igher annealing temperature. Some Ge in the PtGeSi layer segregated to the surface. Both types of Ge segregation were strong after a 3 h, 30 0-degrees-C anneal. The mechanism of the phenomena is discussed. This will have certain affects on the properties of PtGeSi/GeSi Schottky de vices.