EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 2DO.10.1 Electronic Properties and Structure of Boron-Hydrogen Complexes in Crystalline Silicon
Type: Oral
Date: Thursday, 9th September 2021
17:00 - 18:30
Author(s): J.A.T. De Guzman, V.P. Markevich, J. Coutinho, N.V. Abrosimov, M.P. Halsall, A.R. Peaker
Presenter / Speaker: J.A.T. De Guzman, University of Manchester, Manchester, United Kingdom
Event: Conference Conference
Session: 2DO.10 Defects in Silicon and their Characterisation
Topic: 2. 1 Feedstock, Crystallisation, Wafering, Defect Engineering
Keywords: Defects, Silicon, Hydrogen, Deep Level Transient Spectroscopy, LeTID
Summary / Abstract: The significance of hydrogen in the passivation of doping impurities and recombination active defects in silicon is well-established. It has been suggested recently that complexes of hydrogen with boron can be involved in the so-called "light and elevated temperature-induced degradation" (LeTID) in B-doped Si solar cells but the details of the relevant hydrogen-related reactions are not understood. In this work, the subject of hydrogen-boron interactions in crystalline silicon is revisited. We have carried out ab-initio modelling of the structure, binding energy, and electronic properties of complexes incorporating a boron and one or two hydrogen atoms. Further, the electrically active defects have been studied with the use of junction capacitance techniques in n-type Cz-Si samples co-doped with phosphorus and boron and subjected to hydrogenation by different methods. In DLTS spectra of the hydrogenated Si:P+B crystals subjected to reverse bias annealing at 100 oC, an electron emission signal with an activation energy of ~0.175 eV has been detected. The trap is a donor with electronic properties close to those predicted by ab-initio modelling for borondihydrogen (BH2) complex. It is argued that BH2 can be a very efficient recombination center for minority carriers and may be responsible for LeTID in B-doped p-type Si crystals.