Interfacial reactions and electrical characteristics Ti/SiGe/Si(lOO) contact systems

Schottky barrier heights (SBH’S), contact resistivities and solid-phase reactions at the interface of Ti/Si,,Ge,,/Si(lOO) systems have been investigated. At annealing temperatures below 300°C Ti atoms react with Si atoms preferentially. Germanium atoms start to react above 400°C and the formation of C54_Ti(Si,,Ge,.,), IS confirmed by X-ray diffraction after annealing at 650°C. The annealing behavior of SBH’s suggests that Ge atoms are segregated in SiGe layers at the interface, which is consistent with the results on interfacial reactions. For both n- and p-SiGe, the lower SBH’s than Ti/Si(lOO) are obtained at 65O”C, which is considered to be due to the work function of reaction products such as CSCTi(Si, _ ,Ge,), . The contact resistivities smaller than those expected from the SBH’s are obtained for n +- and p+-SiGe at 580°C.