根据太赫兹平面肖特基二极管物理结构, 在理想二极管SPICE参数模型的基础上建立了二极管小信号等效电路模型。依据该二极管等效电路模型设计了基于共面波导(CPW)去嵌方法的二极管S参数在片测试结构, 并对其在0.1~50 GHz、75~110 GHz频率范围内进行了高频小信号测试, 利用测试结果提取了高频下二极管电路模型中各部分电容、电阻以及电感参数。将相应的高频下电容与电阻参数分别与低频经验公式电容值和直流I-V测试提取的电阻值进行了对比, 并利用仿真手段对高频参数模型进行了验证。完整的参数模型以及测试手段相较于理想二极管SPICE模型和传统的参数提取方法可以更为准确地表征器件在高频下的工作状态。该建模思路可用于太赫兹频段非线性电路的优化设计。

Based on the SPICE parameters model of ideal diode, a modified small-signal equivalent circuit model of terahertz planar Schottky diode was built according to the physical structure of the diode. On-wafer device-under-test (DUT) structure based on CPW de-embed method was designed according to the equivalent circuit model of the diode. The small-signal S parameters were measured in the frequency range of 0.1-50 GHz and 75-110 GHz. All the parameters of diode model such as capacitances, resistances and inductances were extracted via the test results. Comparison between DC I-V resistances, empirical formula capacitances and high frequency parameters was made. Both of the capacitances and resistances at high frequencies were different from low frequencies. The built small-signal equivalent circuit model of terahertz planar Schottky diode was validated by simulation and the results of model simulation agree well with the DUT S-parameters. Complete equivalent circuit model and the testing method can more accurately represent the working state of the device under high frequency compared with the ideal diode SPICE model and the parameters of the traditional extraction method. This robust method is suitable for Schottky diode model extraction, which is useful for further nonlinear circuit design and optimization in terahertz wave frequencies.