Properties of a previously unobserved donor-related electrically active defect in Ge induced by alpha particle irradiation

Abstract

Alpha particle irradiation was used to study the radiation-induced defects in n-type germanium (Ge). Investigation of the well-known antimony (Sb)-vacancy complex (commonly known as the E-center) in Ge, with an activation energy of 0.37eV (E0.37), has led to the discovery of another defect with a DLTS signature virtually indistinguishable from the E-center, but with different annealing characteristics. We shall refer to this new defect as the E-prime. Although the two defects are easily distinguishable by annealing, the DLTS signal produced by the E-center and E-prime were not distinguishable through conventional deep level transient spectroscopy (DLTS). Separation of the two peaks was only possible through the use of low noise equipment in conjunction with high resolution Laplace-DLTS. The activation energy of the Sb-vacancy and the E-prime was determined to be 0.370±0.005eV and 0.375±0.005eV. Depth profiles showed uniform distributions of both defects below the Schottky junction.