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2023 (English)In: APL Materials, E-ISSN 2166-532X, Vol. 11, no 3, article id 031107Article in journal (Refereed) Published
Abstract [en]
One of the main challenges in realizing 4H–SiC (silicon carbide)-based bipolar devices is the improvement of minority carrier lifetime in as-grown epitaxial layers. Although Z1/2 has been identified as the dominant carrier lifetime limiting defect, we report on B-related centers being another dominant source of recombination and acting as lifetime limiting defects in 4H–SiC epitaxial layers. Combining time-resolved photoluminescence (TRPL) measurement in near band edge emission and 530 nm, deep level transient spectroscopy, and minority carrier transient spectroscopy (MCTS), it was found that B related deep levels in the lower half of the bandgap are responsible for killing the minority carriers in n-type, 4H–SiC epitaxial layers when the concentration of Z1/2 is already low. The impact of these centers on the charge carrier dynamics is investigated by correlating the MCTS results with temperature-dependent TRPL decay measurements. It is shown that the influence of shallow B acceptors on the minority carrier lifetime becomes neutralized at temperatures above ∼422 K. Instead, the deep B related acceptor level, known as the D-center, remains active until temperatures above ∼570 K. Moreover, a correlation between the deep level concentrations, minority carrier lifetimes, and growth parameters indicates that intentional nitrogen doping hinders the formation of deep B acceptor levels. Furthermore, tuning growth parameters, including growth temperature and C/Si ratio, is shown to be crucial for improving the minority carrier lifetime in as-grown 4H–SiC epitaxial layers.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Materials Engineering Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-192459 (URN)10.1063/5.0142415 (DOI)000953363800003 ()2-s2.0-85150362902 (Scopus ID)
Funder
Swedish Energy Agency, 45398-1Swedish Energy Agency, 43611-1Swedish Research Council, 2020-05444The Research Council of Norway, 325573
Note
Funding: Swedish Energy Agency Energimyndigheten Project [43611-1, 45398-1]; Swedish Research Council VR [2020-05444]; ETH Zurich Postdoctoral Fellowship; Research Council of Norway through the FRIPRO project [325573]; Norwegian Micro- and Nano-Fabrication Facility, NorFab [295864]
2023-03-202023-03-202025-02-10Bibliographically approved