劉新宇

摘 要：根據(jù)高頻毫米波器件和電路的要求，開展具有低Al組分AlGaN緩沖層的HEMT材料的測(cè)試表征和散射機(jī)制研究，研究得到AlGaN緩沖層Al組分增大引起的晶體質(zhì)量下降是二維電子氣電學(xué)性能降低的主要因素；設(shè)計(jì)并生長(zhǎng)了具有AlN背勢(shì)壘的HEMT結(jié)構(gòu)的研究，提高了溝道電子限制，減小器件的短溝道效應(yīng)；優(yōu)化外延材料結(jié)構(gòu)，SiC襯底HEMT材料室溫二維電子氣遷移率大于2200 cm2/Vs，2英寸材料平均方塊電阻255 Ω/m2，方塊電阻不均勻性1.44%。開展器件關(guān)鍵工藝研究能穩(wěn)定得到柵長(zhǎng)80 nm，柵帽寬度1～1.1 μm的T型柵結(jié)構(gòu)，并對(duì)器件表面處理和鈍化技術(shù)做了研究和改進(jìn)。研究解決了SiC襯底減薄、SiC刻蝕技術(shù)、GaN層刻蝕技術(shù)、背孔金屬的填充技術(shù)，成功研制出尺寸為30 μm的方形背孔和圓形背孔。研制成功Ka波段器件，器件fmax>240 GHz。單管輸出功率密度：連續(xù)波：5.25 W/mm；脈沖6.65 W/mm的器件，搭建了Ka波段MMIC在片測(cè)試平臺(tái)。將電流崩塌效應(yīng)、自熱效應(yīng)、短溝道效應(yīng)等融入小信號(hào)和大信號(hào)模型拓?fù)浣Y(jié)構(gòu)，建立Ka波段GaN器件的小信號(hào)和大信號(hào)模型，建立了完善的GaN基HEMT器件模型。

關(guān)鍵詞：氮化鎵 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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