Electrothermal studies of GaN-based high electron mobility transistors with improved thermal designs
Electrothermal studies of GaN-based high electron mobility transistors with improved thermal designs
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DOI：
10.1016/j.ijheatmasstransfer.2017.09.048
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发表时间：
2018-01-01
影响因子：
5.2
通讯作者：
Kronenfeld, Michael Brandon
中科院分区：
文献类型：
--
作者：
Hao, Qing;Zhao, Hongbo;Kronenfeld, Michael Brandon
近年来，GaN高电子迁移率晶体管（HEMT）在大功率和高频应用方面取得了巨大的成就。通常，这些HEMT的性能在很大程度上受到器件内的显著过热的限制，这将显著降低电荷载流子迁移率，从而降低输出电流。为了解决这个问题，已经提出了不同的热管理策略，并且热模拟可能在这里发挥重要作用，以节省大量的实验工作。然而，现有的双光子晶体模拟往往过于简化，不包括电子和声子输运的细节。温度预测的大误差可能会误导这些器件的热改进。在这方面，耦合的电子和声子蒙特卡罗（MC）模拟提供了晶体管区域的最准确的温度预测。为了进一步考虑整个亚毫米器件上的热扩散，声子MC模拟可以与远离晶体管的区域的传统傅立叶定律分析相结合。这种混合动力学模拟最大限度地减少了MC模拟的沉重的计算负荷，但仍然采用了详细的能量传输过程在不同的长度尺度。在这项工作中，这种新的混合仿真技术被用来重新评估一个广泛研究的热管理策略，该策略在设备顶部涂覆高导热层以分散热量。定义为最大温升除以总加热功率，器件热阻也使用声学声子的温升计算。根据傅立叶定律的计算发现差异。研究结果对GaN HEMT的未来发展具有重要的指导意义。(C)2017爱思唯尔有限公司版权所有
In recent years, tremendous efforts have been dedicated to GaN high electron mobility transistors (HEMTs) for high-power and high-frequency applications. In general, the performance of these HEMTs is largely restricted by the significant overheating within the device, which would dramatically reduce the charge carrier mobility and thus lower the output current. To solve this problem, different thermal management strategies have been proposed and electrothermal simulations may play an important role here to save tremendous amounts of experimental efforts. However, existing electrothermal simulations are often oversimplified and do not include the details of electron and phonon transport. The large inaccuracies in temperature predictions can be misleading for the thermal improvement of these devices. In this aspect, coupled electron and phonon Monte Carlo (MC) simulations provide the most accurate temperature predictions of the transistor region. To further take into account the heat spreading across the whole sub-millimeter device, the phonon MC simulations can be coupled with conventional Fourier's law analysis for regions away from the transistor. This hybrid electrothermal simulation minimizes the heavy computational load of MC simulations but still incorporates the detailed energy transport processes at different length scales. In this work, this new hybrid simulation technique is used to re-evaluate one widely studied thermal management strategy that coats a high-thermal-conductivity layer on top of a device to spread out the heat. Defined as the maximum temperature rise divided by the total heating power, the device thermal resistance is also computed using the temperature rise of acoustic phonons. Difference is found from calculations based on the Fourier's law. The results provide important guidance for the future development of GaN HEMTs. (C) 2017 Elsevier Ltd. All rights reserved.