【摘要】 基于SiC衬底成功研制X波段0.25μm栅长带有Γ栅场板结构的AlGaN/GaN HEMT,对比T型栅结构器件,研究了Γ栅场板引入对器件直流、小信号及微波功率特性的影响。结果表明,Γ栅场板结构减小器件截止频率及振荡频率,但明显改善器件膝点电压和输出功率密度。针对场板长度分别为0.4、0.7、0.9、1.1μm,得出一定范围内增加场板长度,器件输出功率大幅度提高,并结合器件小信号模型提参结果分析原因。在频率8 GHz下,总栅宽1 mm,场板长度0.9μm的器件,连续波输出功率密度7.11 W/mm,功率附加效率(PAE)35.31%,相应线性增益10.25 dB。更多还原

【Abstract】 Conventional T-shaped gate and Γ-gate field-plated structures were demonstrated and compared to each other from DC,RF and microwave power characterization.The results show that due to Γ-gate field plate,degradation in the value of unity current gain frequency fT and maximum frequency of oscillation fmax are observed,but there is a significant improvement in knee-voltage and output power density.Also,0.25 μm gate-length AlGaN/GaN HEMTs with varying Γ-gate field-plate lengths of 0.4,0.7,0.9 and 1.1 μm were fabricated on SiC substrates.With the increase of field-plate length within the optimum,output power density is improved dramatically,which is demonstrated by equivalent circuit analysis.At 8 GHz,a continuous-wave output power density is 7.11 W/mm with 35.31% power-added efficiency and 10.25 dB corresponding linear gain at Vds=40 V for an 0.25 μm×1 mm device with field-plate length of 0.9 μm.更多还原