Probing charge transport and background doping in MOCVD grown (010) ${eta}$-Ga$_{2}$O$_{3}$
Probing charge transport and background doping in MOCVD grown (010) ${eta}$-Ga$_{2}$O$_{3}$
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探测 MOCVD 生长 (010) ${eta}$-Ga$_{2}$O$_{3}$ 中的电荷传输和背景掺杂
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发表时间：
2020
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影响因子：
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通讯作者：
Hongping Zhao
中科院分区：
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作者：
Zixuan Feng;A. Bhuiyan;Zhanbo Xia;Wyatt Moore;Zhaoying Chen;Joe F. Mcglone;D. Daughton;A. Arehart;S. Ringel;S. Rajan;Hongping Zhao
用金属有机化学气相沉积方法在(010)半绝缘衬底上生长的非故意掺杂薄膜中，获得了一种新的创纪录的室温电子霍尔迁移率({u}_{rt}=194空间cm^{2}/vSpace S$在$nsim 8 imes 10^{15}空间cm^-3}$)。在45K时，电子迁移率达到峰值sim 9500space cm^{2}/vSpace S。对输运性质的进一步研究表明，在外延层/衬底界面附近存在片状电荷。硅被认为是表面层和界面背景载流子的主要贡献者，源于表面污染和生长环境。预生长氢氟酸清洗衬底后，界面和外延层中的硅杂质明显减少。此外，还研究了MOCVD生长条件，特别是腔室压力对Si杂质掺入的影响。证实了背景电荷浓度与MOCVD生长压力之间的正相关关系。值得注意的是，在体电荷浓度很低的薄膜中，即使降低的表面电荷密度也会对电荷输运性质产生重要的影响。
A new record-high room temperature electron Hall mobility (${mu}_{RT} = 194space cm^{2}/Vspace s$ at $nsim 8 imes 10^{15}space cm^{-3}$) for ${eta}$-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 $sim 9500space cm^{2}/Vspace s$ 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 ${eta}$-Ga2O3 film with very low bulk charge concentration, even a reduced sheet charge density can play an important role in the charge transport properties.