Interfacial reactions and electrical characteristics in Ti/SiGe/Si(100) contact systems

Abstract

Schottky barrier heights (SBH's), contact resistivities and solid-phase reactions at the interface of Ti/Si 0.8Ge 0.2/Si(100) 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 0.88Ge 0.12) 2 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(100) are obtained at 650°C, which is considered to be due to the work function of reaction products such as C54-Ti(Si 1− y Ge y ) 2. The contact resistivities smaller than those expected from the SBH's are obtained for n +- and p +-SiGe at 580°C.