We report on the design and demonstration of β−(Al0.18Ga0.82)2O3/Ga2O3 modulation doped heterostructures to achieve high sheet charge density. The use of a thin spacer layer between the Si delta-doping and heterojunction interface was investigated in β−(Al0.18Ga0.82)2O3/Ga2O3 modulation doped structures. We find that that this strategy enables higher 2DEG sheet charge density up to 6.1x10^12 cm^2 with mobility of 147 cm^2/Vs. The presence of a degenerate 2DEG channel was confirmed by the measurement of low temperature effective mobility of 378 cm^2/V-s and a lack of carrier freeze out from low temperature capacitance voltage measurements. The electron density of 6.1x10^12 cm^2 is the highest reported sheet charge density obtained without parallel conduction channels in an (Al0.18Ga0.82)2O3/Ga2O3 heterostructure system.
@article{arxiv.1910.11521,
title = {High electron density ${\beta}-(Al_{0.18}Ga_{0.82})_2O_3/Ga_2O_3$ modulation doping using ultra-thin (1 nm) spacer layer},
author = {Nidhin Kurian Kalarickal and Zhanbo Xia and Joe Mcglone and Yumo Liu and Wyatt Moore and Aaron Arehart and Steve Ringel and Siddharth Rajan},
journal= {arXiv preprint arXiv:1910.11521},
year = {2019}
}