太赫兹GaAs肖特基混频二极管高频特性分析

在太赫兹波段,存在几种新的高频效应会限制混频二极管的高频特性.应用热电子发射理论和隧道理论,研究了外延层肖特基二极管的高频特性,并以截止频率为品质因数对二极管进行优化设计.研究表明,当二极管工作频率大于等离子频率时,二极管相当于一个电容,失去了混频性能;提高基底掺杂浓度可以减小基底等离子共振效应;外延层等离子频率非常重要并且在研究外延层等离子共振效应时必须考虑传输时间效应;减小阳极直径、减小外延层厚度、提高外延层掺杂浓度可以提高二极管的工作频率.这对太赫兹波段室温混频器件的研制具有重要的参考价值.

Analysis on high frequency performance of THz GaAs Schottky mixer diode

In the THz frequency range,several new high effects will restrict diode high-frequency performance. With the thermionic emission theory and the tunnel theory,the high-frequency performance of epitaxial Schottky diodes is re-evaluated and the structure parameters are optimized with using the cut-off frequency as a figure of merit. The results show that when the operation frequency is higher than the plasma frequency,the diode is equivalent to a capacitance with losing the frequency mixing performance. With the increase of frequency,increasing the doping density of substrate can reduce the substrate plasma resonance effect. The plasma resonance frequency of epitaxial layer is an important factor but transit time effect must be considered. The higher operation frequency can be obtained through reducing the anode diameter and the epilayer thickness,and increasing the epilayer doping density. The results have an important reference value in developing the room temperature THz mixing diodes.