基于AlGaN/GaN HEMT的源漏整体刻蚀欧姆接触结构

研究了源漏整体刻蚀欧姆接触结构对AlGaN/GaN高电子迁移率晶体管(HEMT)的欧姆接触电阻和金属电极表面形貌的影响.利用传输线模型(TLM)对样品的电学性能进行测试,使用原子力显微镜(AFM)对样品的表面形貌进行表征,通过透射电子显微镜(TEM)和X射线能谱仪(EDS)对样品的剖面微结构和界面反应进行表征与分析.实验结果显示,采用Ti/Al/Ni/Au(20 nm/120 nm/45 nm/55 nm)金属和源漏整体刻蚀欧姆接触结构,在合金温度870 c℃,升温20 s,退火50 s条件下,欧姆接触电阻最低为0.13 Ω·mm,方块电阻为363.14 Ω/□,比接触电阻率为4.54×10-7Ω·cm2,形成了良好的欧姆接触,降低了器件的导通电阻.

Recess Ohmic Contact Structure Based on AlGaN/GaN HEMTs

The impacts of the Recess ohmic contact structure on the ohmic contact resistance and the metal electrode surface morphology of the AlGaN/GaN high electron mobility transistors (HEMTs) were studied.The electrical properties of the samples were tested with the transmission line model (TLM).The surface morphology of the samples was characterized by the atomic force microscopy (AFM).The profile microstructure and interfacial reaction of the samples were characterized and analyzed by the transmission electron microscope (TEM) and X-ray energy dispersive spectrometer (EDS).The experimental results show that with the Ti/Al/Ni/Au (20 nm/120 nm/45 nm/55 nm) and Recess ohmic contact structure,and at the alloy temperature of 870 ℃,heating time of 20 s and annealing time of 50 s,the lowest ohmic contact resistance,the square resistance and the specific contact resistivity achieve 0.13 Ω · mm,363.14 Ω/□ and 4.54× 10-7 Ω · cm2,respectively,forming a good ohmic contact.The on-resistance of the device is reduced.