Deep Levels in Electron-Irradiated n- and p-type 4H-SiC Investigated by Deep Level Transient Spectroscopy
The authors have investigated deep levels in electron-irradiated n- and p-type 4H-SiC epilayers by deep level transient spectroscopy (DLTS). By low-energy electron irradiation at 116 keV, the Z1/2 and EH6/7 concentrations are increased in n-type samples, and the concentrations are almost unchanged a...
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Veröffentlicht in: | Materials science forum 2007-09, Vol.556-557, p.331-334 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The authors have investigated deep levels in electron-irradiated n- and p-type 4H-SiC
epilayers by deep level transient spectroscopy (DLTS). By low-energy electron irradiation at 116 keV,
the Z1/2 and EH6/7 concentrations are increased in n-type samples, and the concentrations are almost
unchanged after annealing at 950°C for 30 min. In p-type samples, the unknown centers, namely EP1
and EP2, are introduced by irradiation. By annealing at 950°C, the unknown centers are annealed out.
The HK4 center (EV + 1.44 eV) is increased by the electron irradiation and subsequent annealing at
950°C. The dependence of increase in the trap concentrations by irradiation (NT) on the electron
fluence reveals that NT for the Z1/2 and EH6/7 centers is in proportional to the 0.7 power of electron
fluence, while the slope of the plot is 0.5 for the HK4 center. The Z1/2 and EH6/7 centers show similar
annealing stage and are thermally stable up to 1500-1600°C, while the HK4 center is annealed out at
about 1350°C. The Z1/2 and EH6/7 centers may be derived from a same origin (single carbon vacancy:
VC) but different charge state. The HK4 center may be a complex including VC. |
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ISSN: | 0255-5476 1662-9752 1662-9752 |
DOI: | 10.4028/www.scientific.net/MSF.556-557.331 |