氮化镓多沟道变容二极管研究

现代无线通信技术使用了许多不同频段的方案和输出功率，需要高频高功率的可调器件来构建可调组件以覆盖更大频段，降低系统的组件数量和成本，其中包括高性能的变容二极管。目前常用的变容二极管多为Si或GaAs变容二极管，然而它们都无法同时满足高频高功率的需求。为了使变容二极管更好地应用在无线通讯领域，本论文提出了多沟道的高性能GaN变容二极管。品质因数（Q值）是变容二极管的关键参数：Q值越高，能效越高。虽然GaN出色的材料特性十分适合高频高功率应用，但GaN变容二极管的Q值较低。降低器件电阻是提升Q值的有效方法，但是器件电阻的降低存在较大挑战。本论文提出了一种新型的多沟道AlGaN/GaN变容二极管来降低电阻，提高Q值。使用Silvaco TCAD分别对于平面电极型多沟道GaN变容二极管的外延结构、肖特基型变容二极管器件、MIS结构变容二极管器件进行仿真，证明多沟道结构可以有效降低器件的电阻，提升变容二极管的Q值。通过微纳加工技术制备出1、2、3沟道的平面电极型多沟道GaN变容二极管器件，并使用N5247A PNA-X 微波网络分析仪测试各个器件的S参数。随着频率增大到2.87 GHz以上，Q值随着沟道数目的增大而增大，当工作频率为3.3 GHz时，多沟道变容二极管的Q值相较于单沟道的器件提升了5倍。这些结果说明了多沟道GaN变容二极管的在射频领域的应用潜力。

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