Fabrication and Characterization of Al2O3/InAs Fin Field-Effect Transistors

• Main Authors: Cheng-hsuan Hsieh, 謝承軒
• Other Authors: Jen-inn Chyi
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/97923083246721413585

碩士 === 國立中央大學 === 電機工程學系 === 102 === 　　Because of its narrow band gap, high electron mobility and high electron saturation velocity, InAs is considered a promising candidate for low power consumption field-effect transistors (FETs). Its fin field-effect transistors (FinFETs) might be used in the integrated circuits in the future. However, the interface traps at high-κ/III-V interface, which have significant negative influence on device performance, must be reduced before it can be used for practical applications. In this work, methods of surface treatment for InAs are studied. Nano-scale InAs FinFETs are also demonstrated and characterized. 　　Al2O3 prepared by atomic layer deposition is used as the high-κ material in this study. Before the deposition, various chemical treatments on InAs surface and post metallization annealed are investigated. A proper treatment is proposed to minimize the interface trap density and oxide trap density. 　　The InAs surface channel epi-wafers are grown on GaAs substrates with an Sb-based buffer layer by molecular beam epitaxy. The channel width, ohmic area and gate profile of the FinFETs are defined by electron-beam lithography. The effects of electron beam dosage on photoresist profile and metal profile are examined in this study. Benzocyclobutene planarization process is also employed in this nano-scale device. Al2O3/InAs FinFETs with a gate length of 0.5 μm, source to drain separation of 2 μm and fin width of 60 nm are successfully fabricated. A maximum drain current of 119 μA/μm, a maximum transconductance of 77.2 μS/μm, a threshold voltage of -2.37 V, a drain current on-off ratio of 136 and a sub-threshold swing of 524 mV/decade are obtained.