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Dual‐functional crystalline BeO layer in enhancement‐mode ZnO/Si thin film transistors
Author(s) -
Liang Huili,
Mei Zengxia,
Ye Daqian,
Li Junqiang,
Hong WenChiang,
Zhang Qinghua,
Liu Yaoping,
Gu Lin,
Yu Richeng,
Lu Yicheng,
Du Xiaolong
Publication year - 2017
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201600443
Subject(s) - materials science , amorphous solid , optoelectronics , x ray photoelectron spectroscopy , silicide , high resolution transmission electron microscopy , molecular beam epitaxy , epitaxy , layer (electronics) , thin film transistor , thin film , transmission electron microscopy , nanotechnology , diffusion barrier , silicon , chemical engineering , crystallography , chemistry , engineering
Integration of oxides with Si opens promising opportunities for novel multifunctional devices and new applications. To optimize the device performances through the hybrid integration, keeping the oxide/Si interface abrupt is critically important and challenging due to the seemingly unavoidable formation of amorphous SiO x or silicide interfacial layers. Here, we report an interface‐engineering approach to this issue by molecular beam epitaxy. A BeO thin layer (∼5 nm) was deposited on Si (111) surface using a two‐step process of Be deposition and oxidation. The initially formed BeO served as a template for subsequent homo‐epitaxial growth of a 10‐nm crystalline BeO layer. The well‐defined interface between BeO and Si is clearly discerned by high‐resolution transmission electron microscopy, implying the role of crystalline BeO as a barrier layer against oxygen atoms’ diffusion. High‐resolution X‐ray photoelectron spectroscopy further confirmed that the combined BeO layers sufficiently protect the Si surface from oxidation. A bottom‐gate enhancement‐mode thin film transistor was established on a ZnO (130 nm)/BeO (70 nm)/Si architecture, where BeO was functionalized both as a diffusion barrier and as a high‐ k gate insulator. It indicates that this methodology can be potentially extended to hybrid integration of other technologically important crystalline oxides with Si infrastructures.