聚焦離子束系統輔助砷化銦奈米線歐姆接觸與金氧半場效應電晶體製作

FIB assisted ohmic contact and MOSFET fabrication on InAs nanowire

蔡松澔(Song-Hao Tsai)

指導教授 ： 林浩雄

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.00635

摘要

本論文研究中，我們利用雙束聚焦離子束系統 (Duel-Beam Focus Ion Beam , DBFIB)於砷化銦奈米線 (InAs nanowire)上製作歐姆接觸，並利用其方法，輔助製作單根砷化銦奈米線金氧半場效應電晶體。
砷化銦奈米線來源為氣態分子源分子束磊晶(Gas Source Molecular Beam epitaxy ,GSMBE)所成長。以電子束微影規劃量測電極，並將砷化銦奈米線橋接於電極上，再以雙束聚焦離子束系統中的鎵離子束轟擊砷化銦奈米線表面去除原生氧化層，並以電子束沉積鉑於砷化銦奈米線受轟擊處製作成歐姆接觸。我們分別以傳輸線法量測 (Transmission Line Method ,TML)以及四點探針量測法交互驗證。以傳輸線法所得到砷化銦奈米線之電阻率為4.68×10−3 Ω cm、接觸電阻RC 為1.48 kΩ、特徵接觸電阻為值 ρ_c為1.49×10-6 Ω cm2以及傳輸長度LT為294 nm；而以四點探針量測所得到之砷化銦奈米線之電阻率為3.81×10-3 Ω cm，接觸電阻RC為2.18 k Ω。
最後我們利用電子束微影搭配雙束聚焦離子束系統及原子層累積系統，以三氧化鋁為介電材料製作平面式單根砷化銦奈米線金氧半場效應電晶體。我們發現元件經過氮氫混和氣體熱退火後，修補砷化銦奈米線以及三氧化二鋁的介面缺陷後，能夠提閘極對IDS¬的控制力。量測出元件轉導值 (gm)為76.7μS/μm、次臨界擺幅 (Subthreshold swing , S.S.)為3306 mV/decade、On-Off ratio為28.9、汲極引發能障降低 (Drain Induced Barrier Lowering, DIBL ) 為1429 mV/V以及電子遷移率(electron mobility)為146 cm2/V．s。

關鍵字

砷化銦奈米線 ； 雙束聚焦離子束系統 ； 電子束微影

並列摘要

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 .

並列關鍵字

InAs nanowire ； Dual-Beam Focus Ion Beam ； E-Beam lithography

參考文獻

[19] L. H. Chen, ”Structure and optical properties of InAs nanowire,” National Taiwan University, Taipei, master thesis 2012.

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