CONTACTS ON SI1-X-YGEXCY ALLOYS - ELECTRICAL-PROPERTIES AND THERMAL-STABILITY

In this work, we have investigated the reactions between Zr and SiGeC alloys using rapid thermal annealing. The interactions of the metal fi lms with the Si1-x-yGexCy alloys have been investigated by using sheet resistance measurements, Rutherford backscattering (RBS), energy disp ersive spectroscopy (EDS), and x-ray diffraction. The morphologies of surfaces and interfaces were examined using atomic force microscopy (A FM) and cross-sectional transmission electron microscopy (TEM). The an alyses indicated that the C49-Zr(Si1-zGez)(2) phase is the final phase of the reaction. The ternary alloy even annealed at temperature as hi gh as 800 degrees C indicates the same Ge index x, as in the as-deposi ted Si1-xGex layer. We did not observe any Ge segregation after anneal ing. The results indicate that Zr may be a good candidate for contacts on IV-IV alloys in terms of thermal stability. In addition, we have s tudied the electrical properties of Schottky contacts to SiGeC alloys. We have shown that the dependence of the SBH on the metal work functi on is less pronounced for the alloys than for pure Si. The addition of Ge in the binary alloys always leads to a decrease of the SBH to p ty pe. The incorporation of C results in a large increase of the SBHs and provides the possibility to get field effect on p-type IV-IV alloys b y using Schottky contacts. (C) 1998 American Vacuum Society.