Low Field Vertical Charge Transport in the Channel and Buffer Layers of GaN-on-Si High Electron Mobility Transistors
Low Field Vertical Charge Transport in the Channel and Buffer Layers of GaN-on-Si High Electron Mobility Transistors
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DOI：
10.1109/led.2020.3030341
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发表时间：
2020-12-01
影响因子：
4.9
通讯作者：
Kuball, Martin
中科院分区：
文献类型：
--
作者：
Wach, Filip;Uren, Michael J.;Kuball, Martin
衬底斜坡和阶梯应力瞬态测量被应用于研究GaN-on-Si功率HEMT中的垂直电荷输运机制。通过选择适当的偏置点的基板应力，有可能挑出占主导地位的电荷transportmechanism：在低负偏压下，通过碳掺杂GaN的输运表现为负偏压。（下降）电流瞬变，表观活化能（E-A）= 0.29 eV，而在更大的负电压下，通过非故意掺杂的GaN的输运的特征在于正电荷。（增加）电流瞬变（E-A = 0.38 eV）。我们提出的实验证据发生在C掺杂的GaN和一维跳跃沿着在无意掺杂的GaN的位错的3D可变范围跳跃。通过研究从0至-140 V范围内的10 V电势差的双向电压阶跃获得的瞬态，我们观察到通过位错的跳跃输运在低衬底偏压下显示出非欧姆行为，这表现为时间常数τ强烈依赖于偏压。我们建议，这可以解释的位错核心和2D电子气（2DEG）之间的二极管结的存在。
Substrate ramps and stepped stress transient measurements are applied to study vertical charge transport mechanisms in GaN-on-Si power HEMTs. By choosing appropriate bias points for substrate stress it is possible to single out the dominant charge transportmechanism: at low negative biases transport through carbon-doped GaN manifests itself in negative (decreasing) current transients with apparent activation energy (E-A) = 0.29 eV, while at larger negative voltages transport through unintentionally doped GaN is characterized by positive (increasing) current transients (E-A = 0.38 eV). We present experimental evidence for 3D variable range hopping taking place in C-doped GaN and 1D hopping along the dislocations in unintentionally doped GaN. By investigating transients obtained from bidirectional voltage steps of 10 V potential difference in the range 0 to -140 V, we observe that hopping transport through dislocations shows non-Ohmic behavior at low substrate biases, which manifests itself in a time constant tau strongly dependent on bias. We propose that this can be explained by the existence of a diode junction between the dislocation core and the 2D electron gas (2DEG).