FIB assisted ohmic contact and MOSFET fabrication on InAs nanowire
Date Issued
2015
Date
2015
Author(s)
Tsai, Song-Hao
Abstract
In this thesis, we use Duel-Beam Focus Ion Beam (DBFIB) for forming ohmic contact on InAs nanowire and further apply the method to assist fabricating single InAs nanowire MOSFET. The InAs nanowire was grown by GSMBE system. We use E-Beam lithography and E-Gun evaporator to make bottom electrode then transferring InAs nanowire on it. The InAs nanowire was etched by Ga ion beam in DBFIB system to remove the native oxide coating on the InAs nanowire then we deposit Pt by electron beam on the etched area to form ohmic contact. We use both transmission line method and four point probe method to check the experiment. In the transmission line method, the specific contact resistivity is 1.49×10-6 Ω cm2, contact resistance is 1.48 kΩ, transmission length (LT) is 294 nm and the resistivity of InAs is 4.68×10−3 Ω cm; in the four point probes method, the contact resistance is 2.18 kΩ and the resistivity of InAs is 3.81×10−3 Ω cm. Finally, we applied the E-beam lithography, DBFIB system and Atomic Layer Deposition (ALD) system to fabricate the planer single InAs nanowire MOSFET, and the dielectric material is Al2O¬3.We found that the gate control ability to the IDS was improved due to the forming gas annealing, which can reduce the dangling bonds and improve the interface of Al2O¬3/InAs. The device’s transconductance is 76.7 μS/μm , subthreshold slope is 3306 mV/decade, on-off ratio is 28.9, DIBL is 1429 mV/V and the electron mobility is 146 cm2/V．s .
Subjects
InAs nanowire
Dual-Beam Focus Ion Beam
E-Beam lithography
Type
thesis
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