Impact of growth parameters on the background doping of GaN films grown by ammonia and plasma-assisted molecular beam epitaxy for high-voltage vertical power switches

Autor: Jianfeng Wang, Kelsey Fast Jorgensen, Esmat Farzana, Kai Shek Qwah, Morteza Monavarian, Zachary J. Biegler, Thomas Mates, James S. Speck
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: APL Materials, Vol 9, Iss 8, Pp 081118-081118-7 (2021)
Druh dokumentu: article
ISSN: 2166-532X
DOI: 10.1063/5.0060154
Popis: We report on ammonia and plasma-assisted molecular beam epitaxy (NH3-MBE and PAMBE) grown GaN layers with a low net carrier concentration (Nnet). Growth parameters, such as growth rate, V–III ratio, and plasma power, were investigated on different substrates to study their impact on surface morphology and background doping levels using atomic force microscopy and capacitance–voltage (C–V) measurements, respectively. The elevated growth rates are especially interesting for vertical power switches, requiring very thick drift regions (over 10 μm) with low background concentrations. For our NH3-MBE-grown layers, Nnet shows an almost linear increase with the growth rate. Using a freestanding substrate and at a fast growth rate of 1.4 μm hr−1, a Nnet value as low as 1 × 1015 cm−3 was achieved. For samples grown via PAMBE, the lowest Nnet among samples grown under a Ga adlayer was 2 × 1016 cm−3 for a growth rate of 0.32 μm h−1 on a GaN-on-sapphire template. The results support the use of MBE for growing high-quality GaN material with reasonably fast growth rates maintaining low background doping levels for high-voltage vertical power electronic devices.
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