Low onset voltage of GaN on Si Schottky barrier diode using various recess depths (original) (raw)
2014, Electronics Letters
https://doi.org/10.1049/EL.2014.1747
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Abstract
A low onset voltage AlGaN/GaN diode with a width of 14 mm is achieved. The recess depth of the AlGaN layer is responsible for the low onset voltage. In comparison with the conventional non-recessed diode, the onset voltage reduces by 45% along with a decrease of reverse leakage current by about one order of magnitude.
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References (7)
- Millan, J.: 'Wide band-gap power semiconductor devices', IET Circuits Devices Syst., 2007, 1, (5), pp. 372-379
- Selvaraj, S.L., Suzue, T., and Egawa, T.: 'Breakdown enhancement of AlGaN/GaN HEMTs on 4-in silicon by improving the GaN quality on thick buffer layers', IEEE Electron Device Lett., 2009, 30, (6), pp. 587-589
- Bahat-Treidel, E., Hilt, O., Zhytnytska, R., Wentzel, A., Meliani, C., Wurfl, J., and Trankle, G.: 'Fast-switching GaN-based lateral power Schottky barrier diodes with low onset voltage and strong reverse block- ing', IEEE Electron Device Lett., 2012, 33, (3), pp. 357-359
- Lee, J.-G., Park, B.-R., Cho, C.-H., Seo, K.-S., and Cha, H.-Y.: 'Low turn-on voltage AlGaN/GaN-on-Si rectifier with gated ohmic anode', IEEE Electron Device Lett., 2013, 34, (2), pp. 214-216
- Lee, J.-H., Jeong, J.-H., and Lee, J.-H.: 'Enhanced electrical character- istics of AlGaN-based SBD with in situ deposited silicon carbon nitride cap layer', IEEE Electron Device Lett., 2012, 33, (4), pp. 492-494
- Takatani, K., Nozawa, T., Oka, T., Kawamura, H., and Sakuno, K.: 'AIGaN/GaN Schottky-ohmic combined anode field effect diode with fluoride-based plasma treatment', Electron. Lett., 2008, 44, (4), pp. 320-321
- Shul, R.J., Zhang, L., Baca, A.G., Willison, C.G., Han, J., Pearton, S.J., and Ren, F.: 'Inductively coupled plasma-induced etch damage of GaN p-n junctions', J. Vac. Sci. Technol. A, 2000, 18, (4), pp. 1139-1143
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