The role of chemical potential in compensation control in Si:AlGaN
The role of chemical potential in compensation control in Si:AlGaN
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DOI：
10.1063/1.5132953
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发表时间：
2020-03
影响因子：
3.2
通讯作者：
S. Washiyama;P. Reddy;B. Sarkar;M. H. Breckenridge;Q. Guo;P. Bagheri;A. Klump;R. Kirste;J. Tweedie;S. Mita;Z. Sitar;R. Collazo
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文献类型：
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作者：
S. Washiyama;P. Reddy;B. Sarkar;M. H. Breckenridge;Q. Guo;P. Bagheri;A. Klump;R. Kirste;J. Tweedie;S. Mita;Z. Sitar;R. Collazo
通过化学势控制（CPC）证明了硅掺杂富铝AlGaN的补偿降低。通过热力学过饱和模型，将氮位碳（CN）和Si （VIII + nSiIII）阳离子空位配合物的化学势和生成能与生长变量相关联，定量预测了CN的加入和VIII + nSiIII配合物的生成。补偿“膝盖”行为，即随着硅掺入量的增加而降低电导率，在一定浓度以上得到了成功的控制。在富氮条件下，通过抑制VIII + nSiIII配合物的形成，可以提高最大自由载流子浓度，而通过使生长环境富氮，可以降低CN对杂质的补偿。霍尔效应测量和光致发光的结果与CPC模型的定量理论预测一致。基于所建立的模型，在单晶AlN衬底上，Al0.7Ga0.3N的电导率为160 Ω−1 cm−1，自由载流子浓度为3 × 1019 cm−3。CPC模型所证明的预测能力应该大大减少经验分析或迭代实验，否则将是必要的。
Reduction in compensation in Si-doped Al-rich AlGaN is demonstrated via chemical potential control (CPC). The chemical potentials and the resulting formation energies of carbon on the nitrogen site (CN) and cation vacancy complex with Si (VIII + nSiIII) were related to growth variables through a thermodynamic supersaturation model, which quantitatively predicted the incorporation of CN and the generation of the VIII + nSiIII complex. The compensation “knee” behavior, i.e., decreasing conductivity with increasing Si incorporation beyond a certain concentration, was successfully controlled. The maximum free carrier concentration was improved by impeding the formation of VIII + nSiIII complexes under III-richer conditions, while the impurity compensation by CN was reduced by making the growth environment N-richer. The results of Hall effect measurement and photoluminescence agreed well with quantitative theoretical predictions of the CPC model. Based on the developed model, the highest conductivity of 160 Ω−1 cm−1 with free carrier concentration of 3 × 1019 cm−3 in Al0.7Ga0.3N ever reported was achieved on single crystal AlN substrates. The demonstrated predictive power of the CPC model should greatly reduce the empirical analysis or iterative experimentation that would otherwise be necessary.