1. Impact of Ionizing Radiation on the \SiO2/ \SiC Interface in 4H-SiC BJTs.
- Author
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Usman, Muhammad, Buono, Benedetto, and Hallen, Anders
- Subjects
- *
ELECTRONS , *RADIOACTIVITY , *IRRADIATION , *HELIUM ions , *IONIZING radiation - Abstract
Degradation of \SiO2 surface passivation for 4H-SiC power bipolar junction transistors (BJTs) as a result of ion irradiation has been studied to assess the radiation hardness of these devices. Fully functional BJTs with 2700 V breakdown voltage are implanted with 600 keV helium ions at fluences ranging from \1 \times \10^12 to \1 \times \10^16\ \cm^-2 at room temperature. These ions are estimated to reach the \SiO2/ \SiC interface. The current–voltage characteristics before and after irradiation show that the current gain of the devices starts degrading after a helium fluence of \1\times \10^14\ \cm^-2 and decreases up to 20% for the highest fluence of ions. Simulations show that the helium ions induce ionization inside the \SiO2, which increases the interface charge and leads to a degradation of the BJT performance. Thermal annealing of the irradiated devices at 300 ^\circ \C, 420 ^\circ\C, and 500 ^\circ\C further increases the amount of charge at the interface, resulting in increased base current in the low-voltage range. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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