TY - JOUR
T1 - Mesostructured HfxAlyO2 Thin Films as Reliable and Robust Gate Dielectrics with Tunable Dielectric Constants for High-Performance Graphene-Based Transistors
AU - Lee, Yunseong
AU - Jeon, Woojin
AU - Cho, Yeonchoo
AU - Lee, Min Hyun
AU - Jeong, Seong Jun
AU - Park, Jongsun
AU - Park, Seongjun
PY - 2016/7/26
Y1 - 2016/7/26
N2 - We introduce a reliable and robust gate dielectric material with tunable dielectric constants based on a mesostructured HfxAlyO2 film. The ultrathin mesostructured HfxAlyO2 film is deposited on graphene via a physisorbed-precursor-assisted atomic layer deposition process and consists of an intermediate state with small crystallized parts in an amorphous matrix. Crystal phase engineering using Al dopant is employed to achieve HfO2 phase transitions, which produce the crystallized part of the mesostructured HfxAlyO2 film. The effects of various Al doping concentrations are examined, and an enhanced dielectric constant of ∼25 is obtained. Further, the leakage current is suppressed (∼10-8 A/cm2) and the dielectric breakdown properties are enhanced (breakdown field: ∼7 MV/cm) by the partially remaining amorphous matrix. We believe that this contribution is theoretically and practically relevant because excellent gate dielectric performance is obtained. In addition, an array of top-gated metal-insulator-graphene field-effect transistors is fabricated on a 6 in. wafer, yielding a capacitance equivalent oxide thickness of less than 1 nm (0.78 nm). This low capacitance equivalent oxide thickness has important implications for the incorporation of graphene into high-performance silicon-based nanoelectronics.
AB - We introduce a reliable and robust gate dielectric material with tunable dielectric constants based on a mesostructured HfxAlyO2 film. The ultrathin mesostructured HfxAlyO2 film is deposited on graphene via a physisorbed-precursor-assisted atomic layer deposition process and consists of an intermediate state with small crystallized parts in an amorphous matrix. Crystal phase engineering using Al dopant is employed to achieve HfO2 phase transitions, which produce the crystallized part of the mesostructured HfxAlyO2 film. The effects of various Al doping concentrations are examined, and an enhanced dielectric constant of ∼25 is obtained. Further, the leakage current is suppressed (∼10-8 A/cm2) and the dielectric breakdown properties are enhanced (breakdown field: ∼7 MV/cm) by the partially remaining amorphous matrix. We believe that this contribution is theoretically and practically relevant because excellent gate dielectric performance is obtained. In addition, an array of top-gated metal-insulator-graphene field-effect transistors is fabricated on a 6 in. wafer, yielding a capacitance equivalent oxide thickness of less than 1 nm (0.78 nm). This low capacitance equivalent oxide thickness has important implications for the incorporation of graphene into high-performance silicon-based nanoelectronics.
KW - atomic layer deposition
KW - capacitance equivalent oxide thickness
KW - graphene
KW - mesostructure
KW - phase transition engineering
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U2 - 10.1021/acsnano.6b01734
DO - 10.1021/acsnano.6b01734
M3 - Article
AN - SCOPUS:84979900755
SN - 1936-0851
VL - 10
SP - 6659
EP - 6666
JO - ACS Nano
JF - ACS Nano
IS - 7
ER -