Growth condition dependence of unintentional oxygen incorporation in epitaxial GaN
Growth condition dependence of unintentional oxygen incorporation in epitaxial GaN
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外延 GaN 中无意掺氧的生长条件依赖性
DOI：
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发表时间：
2016
影响因子：
5.5
通讯作者：
S. Schmult
中科院分区：
文献类型：
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作者：
F. Schubert;S. Wirth;F. Zimmermann;J. Heitmann;T. Mikolajick;S. Schmult
摘要 生长条件对分子束外延合成的氮化镓 (GaN) 中无意的背景杂质浓度及其化学和物理性质有巨大影响。特别是对于被确定为主要背景杂质的氧，我们证明在优化的生长化学计量下，生长温度是控制其掺入的关键参数，并且增加 55°C 会导致氧减少一个数量级。通过二次离子质谱、光致发光、电容与电压测量、低温磁输运以及基于二维电子气的横向晶体管测试结构中的寄生电流路径，对这种减少以及由此产生的光学和电学特性进行定量分析。在 665°C 的生长温度下，残余载流子浓度降至 1015 cm−3 以下，从而产生绝缘行为，从而使该材料适合超越最先进的设备应用。
Abstract Growth conditions have a tremendous impact on the unintentional background impurity concentration in gallium nitride (GaN) synthesized by molecular beam epitaxy and its resulting chemical and physical properties. In particular for oxygen identified as the dominant background impurity we demonstrate that under optimized growth stoichiometry the growth temperature is the key parameter to control its incorporation and that an increase by 55 °C leads to an oxygen reduction by one order of magnitude. Quantitatively this reduction and the resulting optical and electrical properties are analyzed by secondary ion mass spectroscopy, photoluminescence, capacitance versus voltage measurements, low temperature magneto-transport and parasitic current paths in lateral transistor test structures based on two-dimensional electron gases. At a growth temperature of 665 °C the residual charge carrier concentration is decreased to below 1015 cm−3, resulting in insulating behavior and thus making the material suitable for beyond state-of-the-art device applications.