SOLID-STATE REACTION OF CO,TI WITH EPITAXIALLY-GROWN SI1-XGEX FILM ON SI(100) SUBSTRATE

The solid state reaction of Co,Ti with an epitaxially grown Si 1-xGex strained layer is investigated in this article. The reaction was performed in a rapid thermal annealing system. The resulting films were characterized by Rutherford backscattering, Auger electron spectroscopy, x-ray photoelectron spectroscopy, x-ray diffractometry, and scanning electron microscopy. The electrical resistivity and Hall effect were measured in the temperature range of 77-300 K. Rapid thermal annealing of Co/Si 0.8Ge0.2 at 650°C results in a Co(Si 0.9Ge0.1) film with cubic crystalline structure. At higher temperature CoSi2 is formed with Ge segregation towards the surface. After a multi-step annealing, a highly oriented CoSi2 layer can be grown. For TiN/Ti/SiGe, the ternary phase of Ti(Si1-yGe y)2 is formed, with a smooth surface and with resistivity comparable to the lowest value exhibited by TiSi2. The Co/Ti/SiGe/Si reaction is studied for the first time, demonstrating that the uniformity of Co/SiGe reaction is improved by applying the Co/Ti bilayer. A TiN(O)/CoSi 2(Ge)/Si multilayer structure is formed, and the CoSi2(Ge) layer exhibits a strongly textured structure. Low temperature measurement reveals that the CoSi2(Ge) layer has a resistivity slightly higher than that of CoSi2. © 1995 American Institute of Physics.