| Autor: |
Murata, K., Tawara, T., Yang, A., Takanashi, R., Miyazawa, T., Tsuchida, H. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 7/28/2019, Vol. 126 Issue 4, pN.PAG-N.PAG, 9p, 1 Chart, 9 Graphs |
| Abstrakt: |
Wide-ranging control of carrier lifetimes in n-type epilayers by vanadium (V) doping is attempted toward not only developing a buffer layer to prevent the stacking fault expansion but also improving switching loss in 4H-SiC-based bipolar devices. Control of V doping concentrations in lightly and highly nitrogen (N)-doped epilayers was achieved within the range of 1012–1015 cm−3 by changing the input flow rates of vanadium tetrachloride. Photoluminescence (PL) and deep-level transient spectroscopy analyses revealed that incorporated V atoms create the PL bands within the range of 0.8–1.0 eV, and densities of the deep center at the V3+/4+ acceptor level (Ec − 0.97 eV) increase linearly with V doping concentrations. Accordingly, V doping shortens the minority carrier lifetimes in lightly N-doped epilayers from 3 μs to 40 ns as well as lifetimes in highly N-doped epilayers down to 20 ns at 20 °C, achieving intrawafer carrier lifetime uniformities of 3–10% σ/mean. Furthermore, V doping during epitaxial growth exhibited a nonsignificant memory effect and the V-doped epilayers showed high thermal stability against postprocessing by 1700 °C. We also demonstrated PiN diodes with a 2.4 μm-thick N + V-doped buffer layer (N: 1 × 1018 and V: 1 × 1014 cm−3), showing no degradation after a stress test for 1 h under a direct current density of 600 A/cm2. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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