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

Germanium movement in the thermal reaction between Pt and the Ge0.15Si0.85/Si heterostructure was studied by Auger electron spectroscopy. The compounds formed were identified by x-ray diffraction after various anneals from 300 to 760-degrees-C. Pt2Ge and Pt2Si formed at low annealing temperatures. At higher temperatures, Pt (GexSi1-x) formed. Two types of Ge segregation were observed. Ge was rich at the surface and the PtGeSi/GeSi interface. Some Ge was pushed inward during thermal reaction at all of the above conditions. This procedure was enhanced by higher annealing temperature. Some Ge in the PtGeSi layer segregated to the surface. Both types of Ge segregation were strong after a 3 h, 300-degrees-C anneal. The mechanism of the phenomena is discussed. This will have certain affects on the properties of PtGeSi/GeSi Schottky devices.