Electrical characterization of defects introduced in Ge during electron beam deposition of different metals

We have used deep level transient spectroscopy to characterize the defects introduced in n-type, Sb-doped, Ge during electron beam deposition of different metals for Schottky contact formation. We have found that the relative concentration of the electron beam induced defects depended on the metal used: metals that required a higher beam intensity to evaporate, e.g. Ru, resulted in larger defect concentrations than metals that required a lower beam intensity, e.g. Pd. The nature of some of these defects could be established by comparing their properties to those of well-known defects introduced by electron irradiation of the same material. The most prominent defect thus identified was the E-center, i.e. the Sb-V center. This defect forms when vacancies, that are introduced during the interaction of energetic metal and other particles with the Ge surface, diffuse into the Ge where they bond to Sb dopant atoms.