The origin of defects induced in ultra-pure germanium by Electron Beam Deposition

The creation of point defects in the crystal lattices of various semiconductors by subthreshold events has been reported on by a number of groups. These observations have been made in great detail using sensitive electrical techniques but there is still much that needs to be clarified. Experiments using Ge and Si were performed that demonstrate that energetic particles, the products of collisions in the electron beam, were responsible for the majority of electron-beam deposition (EBD) induced defects in a two-step energy transfer process. Lowering the number of collisions of these energetic particles with the semiconductor during metal deposition was accomplished using a combination of static shields and superior vacuum resulting in devices with defect concentrations lower than $10^{11}\,$cm$^{-3}$, the measurement limit of our deep level transient spectroscopy (DLTS) system. High energy electrons and photons that samples are typically exposed to were not influenced by the shields as most of these particles originate at the metal target thus eliminating these particles as possible damage causing agents. It remains unclear how packets of energy that can sometimes be as small of 2eV travel up to a $\mu$m into the material while still retaining enough energy, that is, in the order of 1eV, to cause changes in the crystal. The manipulation of this defect causing phenomenon may hold the key to developing defect free material for future applications.Comment: 18 pages, 9 figure

Rate theory of acceleration of the defect annealing driven by discrete breathers

Novel mechanisms of defect annealing in solids are discussed, which are based on the large amplitude anharmonic lattice vibrations, a.k.a. intrinsic localized modes or discrete breathers (DBs). A model for amplification of defect annealing rate in Ge by low energy plasma-generated DBs is proposed, in which, based on recent atomistic modelling, it is assumed that DBs can excite atoms around defects rather strongly, giving them energy $\gg k_BT$ for $\sim$100 oscillation periods. This is shown to result in the amplification of the annealing rates proportional to the DB flux, i.e. to the flux of ions (or energetic atoms) impinging at the Ge surface from inductively coupled plasma (ICP)Comment: 18 pages, 11 figures. arXiv admin note: text overlap with arXiv:1406.394

A study of the T2 defect and the emission properties of the E3 deep level in annealed melt grown ZnO single crystals

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Deep level transient spectroscopy (DLTS) study of defects introduced in antimony doped Ge by 2 MeV proton irradiation

Deep level transient spectroscopy (DLTS) and Laplace-DLTS have been used to investigate the defects created in Sb doped Ge after irradiation with 2 MeV protons having a fluence of 1×1013 protons/cm2. The results show that proton irradiation resulted in primary hole traps at EV +0.15 and EV +0.30 eV and electron traps at EC −0.38, EC −0.32, EC −0.31, EC −0.22, EC −0.20, EC −0.17, EC −0.15 and EC −0.04 eV. Defects observed in this study are compared with those introduced in similar samples after MeV electron irradiation reported earlier. EC −0.31, EC −0.17 and EC −0.04, and EV +0.15 eV were not observed previously in similar samples after high energy irradiation. Results from this study suggest that although similar defects are introduced by electron and proton irradiation, traps introduced by the latter are dose dependent.South African National Research Foundation and Monash University, South Afric

Electrical characterization of defects in heavy-ion implanted n-type Ge

Deep-level transient spectroscopy was used to investigate the electrically active defects introduced in n-type Ge during heavy-ion implantation of 160 keV ions. Various noble heavy-ions were used for implantation and the main defects introduced were found to be electron traps with energy levels at E-C - 0.09 eV, E-C - 0.15 eV and E-C - 0.30 eV. Another defect with a level at E-C - 0.38 eV, shown to be the E-center (V-Sb defect), is also present in a very low concentration. The main defects in heavy-ion implanted Ge are different from those introduced by MeV electron irradiation, where the main defect is the E-center. Since electron irradiation introduces mainly point defects, this indicates that heavy-ion implantation introduces defects of a more extended nature, such as vacancy and/or interstitial clusters and their combinations with impurities or foreign species in the Ge. We have also demonstrated that these defects are not species related. (C) 2007 Elsevier B.V. All rights reserved.status: publishe