Atomic Layer Deposition of Al2O3 on WSe2 Functionalized by Titanyl Phthalocyanine

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• 作者：Jun Hong Park ; Sara Fathipour ; Iljo Kwak ; Kasra Sardashti ; Christopher F. Ahles ; Steven F. Wolf ; Mary Edmonds ; Suresh Vishwanath ; Huili Grace Xing ; Susan K. Fullerton-Shirey ; Alan Seabaugh ; Andrew C. Kummel
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：July 26, 2016
• 年：2016
• 卷：10
• 期：7
• 页码：6888-6896
• 全文大小：602K
• 年卷期：0
• ISSN：1936-086X

文摘

To deposit an ultrathin dielectric onto WSe₂, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al₂O₃ on WSe₂. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H₂O nucleate on the TiOPc, resulting in a uniform deposition of Al₂O₃, as confirmed by atomic force microscopy and cross-sectional transmission electron microscopy. The field-effect transistors (FETs) formed using this process have a leakage current of 0.046 pA/μm² at 1 V gate bias with 3.0 nm equivalent oxide thickness, which is a lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade.