Mobility limiting scattering mechanisms in nitride-based two-dimensional heterostructures with the InGaN channel
Mobility limiting scattering mechanisms in nitride-based two-dimensional heterostructures with the InGaN channel
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DOI：
10.1088/0268-1242/25/4/045024
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发表时间：
2010-04
影响因子：
1.9
通讯作者：
S. Gökden;R. Tülek;A. Teke;J. Leach;Q. Fan;J. Xie;Ü. Özgür;H. Morkoç;S. B. Lişesivdin;E. Özbay
中科院分区：
文献类型：
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作者：
S. Gökden;R. Tülek;A. Teke;J. Leach;Q. Fan;J. Xie;Ü. Özgür;H. Morkoç;S. B. Lişesivdin;E. Özbay
研究了AlInN/AlN/InGaN/GaN二维电子气（2DEG）异质结中限制载流子迁移率的散射机制，并与无InGaN沟道的器件进行了比较。虽然预期InGaN将导致比GaN相对更高的电子迁移率，但是与GaN相比，对于具有InGaN沟道的样品测量的霍尔迁移率低得多。为了研究这些观察的主要散射过程，包括声学和光学声子，电离杂质，界面粗糙度，位错和合金无序被施加到温度相关的迁移率数据。结果发现，散射主要是由于界面粗糙度限制了具有InGaN通道的样品在低和中温下的电子迁移率。通过光学声子和界面粗糙度散射的组合确定的室温电子迁移率在630和910 cm 2（Vs）-1之间测量，相应的片状载流子密度为2.3-1.3 × 1013 cm-2。另一方面，在一项研究中，对于Al0.82In0.18N/AlN/GaN和Al0.3Ga0.7N/AlN/GaN异质结构，电子迁移率主要受到本征散射过程的限制，例如在整个温度范围内的声学和光学声子，其中室温电子迁移率被发现为1630和1573 cm 2（Vs）。-1，对应的载片密度分别为1.3和1.1 × 1013 cm-2。通过这些分析，可以得出结论，HEMT结构与InGaN沟道层的界面不如使用AlGaN或AlInN势垒的常规GaN沟道的界面好。还可以指出，随着AlInN势垒层中In含量的增加，界面变得更平滑，导致更高的电子迁移率。
The scattering mechanisms limiting the carrier mobility in AlInN/AlN/InGaN/GaN two-dimensional electron gas (2DEG) heterostructures were investigated and compared with devices without InGaN channel. Although it is expected that InGaN will lead to relatively higher electron mobilities than GaN, Hall mobilities were measured to be much lower for samples with InGaN channels as compared to GaN. To investigate these observations the major scattering processes including acoustic and optical phonons, ionized impurity, interface roughness, dislocation and alloy disorder were applied to the temperature-dependent mobility data. It was found that scattering due mainly to interface roughness limits the electron mobility at low and intermediate temperatures for samples having InGaN channels. The room temperature electron mobilities which were determined by a combination of both optical phonon and interface roughness scattering were measured between 630 and 910 cm2 (V s)−1 with corresponding sheet carrier densities of 2.3–1.3 × 1013 cm−2. On the other hand, electron mobilities were mainly limited by intrinsic scattering processes such as acoustic and optical phonons over the whole temperature range for Al0.82In0.18N/AlN/GaN and Al0.3Ga0.7N/AlN/GaN heterostructures where the room temperature electron mobilities were found to be 1630 and 1573 cm2 (V s)−1 with corresponding sheet carrier densities of 1.3 and 1.1 × 1013 cm−2, respectively. By these analyses, it could be concluded that the interfaces of HEMT structures with the InGaN channel layer are not as good as that of a conventional GaN channel where either AlGaN or AlInN barriers are used. It could also be pointed out that as the In content in the AlInN barrier layer increases the interface becomes smoother resulted in higher electron mobility.