刘新宇

摘 要：根据高频毫米波器件和电路的要求，开展具有低Al组分AlGaN缓冲层的HEMT材料的测试表征和散射机制研究，研究得到AlGaN缓冲层Al组分增大引起的晶体质量下降是二维电子气电学性能降低的主要因素；设计并生长了具有AlN背势垒的HEMT结构的研究，提高了沟道电子限制，减小器件的短沟道效应；优化外延材料结构，SiC衬底HEMT材料室温二维电子气迁移率大于2200 cm2/Vs，2英寸材料平均方块电阻255 Ω/m2，方块电阻不均匀性1.44%。开展器件关键工艺研究能稳定得到栅长80 nm，栅帽宽度1～1.1 μm的T型栅结构，并对器件表面处理和钝化技术做了研究和改进。研究解决了SiC衬底减薄、SiC刻蚀技术、GaN层刻蚀技术、背孔金属的填充技术，成功研制出尺寸为30 μm的方形背孔和圆形背孔。研制成功Ka波段器件，器件fmax>240 GHz。单管输出功率密度：连续波：5.25 W/mm；脉冲6.65 W/mm的器件，搭建了Ka波段MMIC在片测试平台。将电流崩塌效应、自热效应、短沟道效应等融入小信号和大信号模型拓扑结构，建立Ka波段GaN器件的小信号和大信号模型，建立了完善的GaN基HEMT器件模型。

关键词：氮化镓 毫米波 微波功率

Abstract：In accordance with the requirements of high frequency scattering mechanisms millimeter-wave devices and circuits ， low Al content AlGaN buffer layer HEMT materials was researched.study design and grown AlN back barrier having a HEMT structure， improving the electronic channel restrictions of 2EDG By optimizing epitaxial material structure， the mobility of AlGaN/GaN HEMT structure on SIC substrate is greater than 2 200 cm2/Vs，2 inches of average sheet resistance is 255 Ω/m2，sheet resistance unifoumity of is 1.44 percent or below.Targeted research work carried out to optimize the device structure. gate foot length is near 80nm for a T-gate with cap width of 1～1.1μm. and the device surface treatment and passivation techniques are improved. Study and solve the SiC substrate thinning， SiC etching technology，GaN layer etching technique，back via hole metal technology， successfully developed a hole the size of 30um square back and round the back of the hole.The successful development of Ka-band device， the device with fmax> 240 GHz is archeived. Single-tube output power density：Continuous Wave power density is 5.25 W/mm； pulse density 6.65 W/mm devices.The current collapse effect， self-heating effects， short-channel effects is considers by a second curcuit， The small and large signal Ka-band GaN device model were established.

Key Words：Gallium Nitride；Millimeter Wave；Microwave Power Device

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