GaN基HEMT栅终端场板结构研究

Study on the Gate-Terminated Field-Plates for GaN-Based HEMT

制作了带有栅终端场板结构的GaN基HEMT,研究了击穿电压与场板长度的关系,提取了最佳场板长度为0.4,0.5,0.6μm时所对应的栅漏击穿电压最大,为120 V。研究了栅终端场板对器件小信号特性和大信号的影响,栅终端场板长度0.4μm时,器件特征频率及最大振荡频率减小量最小。在栅宽1 mm、频率8 GHz、无场板器件最大工作电压28 V时,连续波输出功率3.2 W,功率增益4.0 dB,功率附加效率17.0%;栅终端场板器件最大工作电压38 V时,连续波输出功率5.1 W,功率增益4.1 dB,功率附加效率21.0%。

GaN-based HEMT with the gate-terminated field plate was fabricated. Its breakdown voltage as a function of the length of field plates （Lfp） was studied and optimized. The maximum of gate-drain breakdown voltage was 120 V when Lfp varied between 0.4 μm to 0.6 μm. The decrease of the cut off frequency and the maximum frequency of oscillation caused by the field plates was minimized when LFP equaled to 0.4μm. At 8 GHz, device with lmm gate-width device with field plates showed a continuous wave output power of 5.1 W （ Vds = 38 V） with a large signal gain of 4.1 dB and a power added efficiency of 21.0% compared to 3.2 W, 4.0 dB and 17%, respectively, for device without the field plates.