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Polymer‐Assisted Deposition of Al‐Doped HfO 2 Thin Film with Excellent Dielectric Properties
Author(s) -
Park Gyeongbae,
Yang Heeseung,
Lee Ju Hyun,
Lee Gilwoon,
Kwak Junghyeok,
Jeong Unyong
Publication year - 2019
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201900588
Subject(s) - materials science , dielectric , high κ dielectric , amorphous solid , doping , thin film , atomic layer deposition , band gap , permittivity , analytical chemistry (journal) , optoelectronics , nanotechnology , crystallography , organic chemistry , chemistry
Demands for high‐ k dielectric materials increase as transistors scale down. One of the promising high‐ k dielectric materials is HfO 2 owing to its large band gap, high dielectric constant, and excellent physical/chemical stability. Although several cost‐effective solution‐based deposition methods have been developed, their dielectric performances are inferior to those obtained by vacuum processes (e.g., atomic layer deposition, sputtering). This study demonstrates a solution‐based polymer‐assisted deposition (PAD) of high‐ k Al‐doped HfO 2 thin films exhibiting remarkable dielectric performances comparable to the conventional deposition methods. The PAD ensures the control of film thickness (≥3 nm) and the homogenous Al doping in the entire thin film. The key to the success is HCl‐mediated coordination of metal precursor and polymer. Thorough analysis on the structure and chemical composition of the dielectric layer is carried out. It is found that the phase transition from monoclinic phase to a mixture of tetragonal and amorphous phases results in excellent dielectric properties. The 7.8 nm thick thin film doped with 4.1 at% of Al exhibits a high dielectric constant of 30.2 with a high areal capacitance (674 nF cm −2 at 1.0 kHz), a low leakage current (3.3 × 10 −9 A cm −2 at 2.0 MV cm −1 ), and a high breakdown voltage (7.7 V).