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Electronic Properties and Structure of Boron-Hydrogen Complexes in Crystalline Silicon
J.A.T. De Guzman, V.P. Markevich, J. Coutinho, N.V. Abrosimov, M.P. Halsall, A.R. Peaker
Defects, Hydrogen, Silicon, Deep Level Transient Spectroscopy, LeTID
Silicon Materials and Cells
Subtopic: Feedstock, Crystallisation, Wafering, Defect Engineering
Event: 38th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2DO.10.1
186 - 190
ISBN: 3-936338-78-7
Paper DOI: 10.4229/EUPVSEC20212021-2DO.10.1
0,00 EUR
Document(s): paper


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.