A new record-high room temperature electron Hall mobility (μRT=194cm2/Vs at n∼8×1015cm−3) for β-Ga2O3 is demonstrated in the unintentionally doped thin film grown on (010) semi-insulating substrate via metalorganic chemical vapor deposition (MOCVD). A peak electron mobility of ∼9500cm2/Vs is achieved at 45 K. Further investigation on the transport properties indicate the existence of sheet charges near the epi-layer/substrate interface. Si is identified as the primary contributor to the background carrier in both the epi-layer and the interface, originated from both surface contamination as well as growth environment. Pre-growth hydrofluoric acid cleaning of the substrate lead to an obvious decrease of Si impurity both at interface and in epi-layer. In addition, the effect of MOCVD growth condition, particularly the chamber pressure, on the Si impurity incorporation is studied. A positive correlation between the background charge concentration and the MOCVD growth pressure is confirmed. It is noteworthy that in a β-Ga2O3 film with very low bulk charge concentration, even a reduced sheet charge density can play an important role in the charge transport properties.
@article{arxiv.2004.13089,
title = {Probing charge transport and background doping in MOCVD grown (010) ${\beta}$-Ga$_{2}$O$_{3}$},
author = {Zixuan Feng and A F M Anhar Uddin Bhuiyan and Zhanbo Xia and Wyatt Moore and Zhaoying Chen and Joe F. McGlone and David R. Daughton and Aaron R. Arehart and Steven A. Ringel and Siddharth Rajan and Hongping Zhao},
journal= {arXiv preprint arXiv:2004.13089},
year = {2020}
}