Plasma-enhanced atomic layer deposition of hafnium silicate thin films using a single source precursor

Kim, Jaehwan; Van, Tran Thi Ngoc; Oh, Jungkeun; Bae, Seung-Muk; Lee, Jun Young; Shong, Bonggeun; Hwang, Jin‐Ha

doi:10.1016/j.ceramint.2020.01.002

Cited by 3 publications

(3 citation statements)

References 43 publications

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“…These precursors, however, sometimes have drawbacks such as halide contamination and low stabilities in the case of the halide and alkoxides, respectively. Consequently, heteroleptic precursors including more than one type of ligands such as cyclopentadienyl (Cp)-alkoxides and Cp-alkylamides are developed, to enhance the thermal stability of precursors of the ALD high-k oxides. − When ozone is used as the oxygen source, ALD using zirconium and hafnium Cp-alkylamide precursors shows high growth per cycle (GPC), ranging from 0.8 to 0.9 Å per cycle, and the deposited films mostly possessed low levels of nitrogen and carbon contamination. Especially, ZrO 2 and HfO 2 films deposited using CpZr(N(Me 2 ) 3 and CpHf(N(Me 2 ) 3 precursors (Me = CH 3 ) and ozone have shown improved film density and electrical performance, possibly due to the deposition temperatures being as high as 350 °C.…”

Section: Introductionmentioning

confidence: 99%

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

et al. 2022

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Deposition of high-k dielectric thin films is essential for manufacturing modern electronic devices. Atomic layer deposition (ALD) is an attractive technology for depositing high-k materials because it exhibits conformality and facilitates thickness control of the films at the atomic level. It has been suggested that high-temperature ALD can enhance the material properties of the deposited films such as density and crystallinity, for which the development of thermally stable precursors that deliver the metallic element is required. Heteroleptic titanium (Ti), zirconium (Zr), and hafnium (Hf) precursors containing amido and cyclopentadienyl (Cp) ligands have recently been introduced, with some demonstrating improved thermal stability. However, the mechanism behind the improved thermal stability of these precursors remains unclear. This research employs density functional theory (DFT) calculations to elucidate the role of Cp ligands of group 4 (Ti, Zr, Hf) precursors for high-temperature ALD. The surface adsorption reactions of the precursors on oxide surfaces are suggested to be facile. For most precursors, one or two ligands are thought to exist after chemical adsorption. Cp ligands, in particular, are expected to persist on the surface, whereas amido ligands are more easily eliminated during adsorption. The decomposition of the precursor after adsorption on the surface then is considered, for which the thermal stability is significantly enhanced by introducing the Cp ligand. Furthermore, precursors with Cp ligands are more difficult to adsorb on the partially decomposed precursor-on-surface. Our findings intend to offer a fundamental molecular-level understanding of the thermal stability of group 4 precursors for high-temperature ALD.

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Section: Introductionmentioning

confidence: 99%

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

et al. 2022

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“…Furthermore, as the composition is determined by the molecular reactivity of the single precursor, such approach is limited in the arbitrary adjustment of the composition. 25 The second is the codosing method (A + B → O) by pulsing two precursors together. As the growth of film relies on the competitive adsorption of the two precursors depending on their amount and reactivity, the uniform coating characteristics of the complex structure might be potentially deteriorated.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, it is difficult to develop new precursors suitable for ALD. Furthermore, as the composition is determined by the molecular reactivity of the single precursor, such approach is limited in the arbitrary adjustment of the composition . The second is the co-dosing method (A + B → O) by pulsing two precursors together.…”

Section: Introductionmentioning

confidence: 99%

Effects of Al Precursors on the Characteristics of Indium–Aluminum Oxide Semiconductor Grown by Plasma-Enhanced Atomic Layer Deposition

Lee

Mun

et al. 2021

ACS Appl. Mater. Interfaces

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Atomic layer deposition (ALD) has attracted much attention, particularly for applications in nanoelectronics because of its atomic-level controllability and high-quality products. In this study, we developed a plasma-enhanced atomic layer deposition (PEALD) process to fabricate a homogeneous indium aluminum oxide (IAO) semiconductor film. Trimethylaluminum (TMA) and dimethylaluminum isopropoxide (DMAI) were used as Al precursors, which yielded different compositions. Density functional theory (DFT) calculations on the surface reactions between indium and aluminum precursors showed that while highly reactive TMA would etch In, DMAI with lower reactivity would allow indium to persist in the films, resulting in a more controlled doping of Al. The In/Al composition ratio could be further precisely controlled by adjusting the indium precursor dose time to sub-saturation. IAO based on DMAI was applied to fabricate thin-film transistors (TFTs), showing that Al can be a carrier suppressor of indium oxide. TFTs with PEALD IAO containing 3.8 atomic % Al showed a turn-on voltage of −0.4 ± 0.3 V, a subthreshold slope of 0.09 V/decade, and a field effect mobility of 18.9 cm 2 /(V s).

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Commercialization of single-source precursors: Applications, intellectual property, and technology transfer

Hepp¹,

Harris

Apblett

et al. 2022

Nanomaterials via Single-Source Precursors

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Plasma-enhanced atomic layer deposition of hafnium silicate thin films using a single source precursor

Cited by 3 publications

References 43 publications

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

Role of Cyclopentadienyl Ligands of Group 4 Precursors toward High-Temperature Atomic Layer Deposition

Effects of Al Precursors on the Characteristics of Indium–Aluminum Oxide Semiconductor Grown by Plasma-Enhanced Atomic Layer Deposition

Commercialization of single-source precursors: Applications, intellectual property, and technology transfer

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