I. Yanilkin, A. Gumarov, I. Golovchanskiy, A. Kiiamov, B. Gabbasov, Roman Yusupov, Lenar Tagirov
This study demonstrates capabilities of a molecular beam epitaxy method for the deposition of ferromagnetic Pd–Fe alloy thin films with variable compositions across film thickness. It is proposed as a technological route to synthesize graded magnetic materials possessing unusual physical properties. A particular approach to realize a concentration profile through temperature control of an effusion cell during deposition is described in detail. Using this technique, graded ferromagnetic films were synthesized and characterized to reveal the possibility of controlling the spectrum of standing spin waves in them. Limitations of creating Pd–Fe films magnetically profiled across the thickness are discussed, associated with the thermal inertia of effusion cells and possible phase separation.
{"title":"Molecular beam epitaxy of Pd-Fe graded alloy films for standing spin waves control","authors":"I. Yanilkin, A. Gumarov, I. Golovchanskiy, A. Kiiamov, B. Gabbasov, Roman Yusupov, Lenar Tagirov","doi":"10.1116/6.0003721","DOIUrl":"https://doi.org/10.1116/6.0003721","url":null,"abstract":"This study demonstrates capabilities of a molecular beam epitaxy method for the deposition of ferromagnetic Pd–Fe alloy thin films with variable compositions across film thickness. It is proposed as a technological route to synthesize graded magnetic materials possessing unusual physical properties. A particular approach to realize a concentration profile through temperature control of an effusion cell during deposition is described in detail. Using this technique, graded ferromagnetic films were synthesized and characterized to reveal the possibility of controlling the spectrum of standing spin waves in them. Limitations of creating Pd–Fe films magnetically profiled across the thickness are discussed, associated with the thermal inertia of effusion cells and possible phase separation.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"3 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aneta S. Stodolna, Shyama Ramankutty, Michiel Blauw, Tommy de Jonge, Arnold J. Storm, J. F. M. Velthuis
The knowledge of atomic hydrogen recombination coefficient (γ) is essential for plasma simulations to calculate accurate atomic hydrogen fluxes. However, γ is a complex material property, and it is affected by the experimental conditions under which it is measured. Therefore, values of γ can differ even by a few orders of magnitude for the same material. In this paper, we demonstrate measurements of hydrogen recombination coefficients at room temperature using an in-house-built catalytic sensor for two selected materials: aluminum Al-5083 (alimex) and stainless steel 316 l, under the load of low-temperature H2 plasma with an admixture of H2O or N2 gases. The plasma settings were carefully chosen to mimic properties of the so-called extreme ultraviolet-generated plasma.1 The measured γ values agree well with literature data obtained for similar plasma conditions and show a correlation with ion energy. Additionally, we show a novel application of the sensor for indirect measurements of the reduction of oxidized surfaces as a function of ion dose. In these experiments, a correlation between reduction time and background water pressure is observed.
{"title":"Measurements of atomic hydrogen recombination coefficients and the reduction of Al2O3 using a heat flux sensor","authors":"Aneta S. Stodolna, Shyama Ramankutty, Michiel Blauw, Tommy de Jonge, Arnold J. Storm, J. F. M. Velthuis","doi":"10.1116/6.0003544","DOIUrl":"https://doi.org/10.1116/6.0003544","url":null,"abstract":"The knowledge of atomic hydrogen recombination coefficient (γ) is essential for plasma simulations to calculate accurate atomic hydrogen fluxes. However, γ is a complex material property, and it is affected by the experimental conditions under which it is measured. Therefore, values of γ can differ even by a few orders of magnitude for the same material. In this paper, we demonstrate measurements of hydrogen recombination coefficients at room temperature using an in-house-built catalytic sensor for two selected materials: aluminum Al-5083 (alimex) and stainless steel 316 l, under the load of low-temperature H2 plasma with an admixture of H2O or N2 gases. The plasma settings were carefully chosen to mimic properties of the so-called extreme ultraviolet-generated plasma.1 The measured γ values agree well with literature data obtained for similar plasma conditions and show a correlation with ion energy. Additionally, we show a novel application of the sensor for indirect measurements of the reduction of oxidized surfaces as a function of ion dose. In these experiments, a correlation between reduction time and background water pressure is observed.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"7 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ion-neutral reactive collision model DNT+, which generates comprehensive ion-neutral collision cross section (CS) data sets for atoms and nonpolar molecules, has been extended to polar molecules. The extension is based on the average dipole orientation (ADO) theory, which adds the dipole moment to Langevin–Hassé CS. Furthermore, the ADO CS for short-range reactive collisions is covered with a rigid core to incorporate long-range elastic and charge-exchange collisions. The modified version of DNT+, i.e., DNT+DM, is applied to gas-phase H2O+–H2O and low-energy CF3+–CO collisions for its validation. The cross sections (CSs) for those collisions using DNT+DM show good agreement with literature data, proving that DNT+DM is valid to some extent. Help with ion swarm analyses and measurements is needed to make the predicted CSs more accurate.
{"title":"Extension of ion-neutral reactive collision model DNT+ to polar molecules based on average dipole orientation theory","authors":"K. Denpoh, Taiki Kato, Masaaki Matsukuma","doi":"10.1116/6.0003762","DOIUrl":"https://doi.org/10.1116/6.0003762","url":null,"abstract":"The ion-neutral reactive collision model DNT+, which generates comprehensive ion-neutral collision cross section (CS) data sets for atoms and nonpolar molecules, has been extended to polar molecules. The extension is based on the average dipole orientation (ADO) theory, which adds the dipole moment to Langevin–Hassé CS. Furthermore, the ADO CS for short-range reactive collisions is covered with a rigid core to incorporate long-range elastic and charge-exchange collisions. The modified version of DNT+, i.e., DNT+DM, is applied to gas-phase H2O+–H2O and low-energy CF3+–CO collisions for its validation. The cross sections (CSs) for those collisions using DNT+DM show good agreement with literature data, proving that DNT+DM is valid to some extent. Help with ion swarm analyses and measurements is needed to make the predicted CSs more accurate.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"88 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Artyushkova, Stuart R. Leadley, Alexander G. Shard
X-ray sources with a photon energy higher than 2140 eV are increasingly being used for routine x-ray photoelectron spectroscopy (XPS) on laboratory-based instruments. This analytical approach is termed “HAXPES” (hard x-ray photoelectron spectroscopy). This article provides an overview of the current and potential future uses of laboratory-based HAXPES in comparison to routine XPS performed using Al Kα and Mg Kα x-ray sources. The standardization of XPS has occurred over 30 years and many of the procedures and reference works are specific to the use of Al Kα and Mg Kα x-ray sources. In this article, we discuss the translation of standard XPS practices to HAXPES, indicate useful resources for HAXPES users, and highlight areas where there is a need for improved information and guidance.
光子能量高于 2140 eV 的 X 射线源越来越多地被用于实验室仪器上的常规 X 射线光电子能谱分析 (XPS)。这种分析方法被称为 "HAXPES"（硬 X 射线光电子能谱）。与使用 Al Kα 和 Mg Kα X 射线源进行的常规 XPS 相比，本文概述了基于实验室的 HAXPES 目前和未来的潜在用途。XPS 的标准化工作已经进行了 30 多年，许多程序和参考文献都是专门针对使用 Al Kα 和 Mg Kα X 射线源的。在本文中，我们将讨论如何将标准 XPS 实践转化为 HAXPES，为 HAXPES 用户指出有用的资源，并强调需要改进信息和指导的领域。
{"title":"Introduction to reproducible laboratory hard x-ray photoelectron spectroscopy","authors":"K. Artyushkova, Stuart R. Leadley, Alexander G. Shard","doi":"10.1116/6.0003740","DOIUrl":"https://doi.org/10.1116/6.0003740","url":null,"abstract":"X-ray sources with a photon energy higher than 2140 eV are increasingly being used for routine x-ray photoelectron spectroscopy (XPS) on laboratory-based instruments. This analytical approach is termed “HAXPES” (hard x-ray photoelectron spectroscopy). This article provides an overview of the current and potential future uses of laboratory-based HAXPES in comparison to routine XPS performed using Al Kα and Mg Kα x-ray sources. The standardization of XPS has occurred over 30 years and many of the procedures and reference works are specific to the use of Al Kα and Mg Kα x-ray sources. In this article, we discuss the translation of standard XPS practices to HAXPES, indicate useful resources for HAXPES users, and highlight areas where there is a need for improved information and guidance.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"34 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141649396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Kuzmenko, Alexander Melnikov, Alexandr Isaev, A. Miakonkikh
The possibilities of optimization of the two-step atomic layer etching process for HfO2 in conventional plasma etching tools were studied. The surface modification step was realized in Ar/CF4/H2 plasma, and the reaction between the modified layer and the surface was activated by Ar ion bombardment from the plasma in the second step. Investigation of the effects of activation step duration, DC bias during activation, and Ar plasma density was carried out. The mechanism of the etching process has been shown to involve fluorination of oxide during the modification step and subsequent removal of fluorine-containing particles at the activation step. An increase in parasitic sputtering rate and lower process saturation with the growth of DC bias during activation was demonstrated. The advantage of the ALE process in lower surface roughness over the conventional etching process was shown. Similar etching characteristics of HfO2 and ZrO2 suggest a similarity in the etching process for the mixed hafnium-zirconium oxide material.
{"title":"Revealing the controlling mechanisms of atomic layer etching for high-k dielectrics in conventional inductively coupled plasma etching tool","authors":"V. Kuzmenko, Alexander Melnikov, Alexandr Isaev, A. Miakonkikh","doi":"10.1116/6.0003717","DOIUrl":"https://doi.org/10.1116/6.0003717","url":null,"abstract":"The possibilities of optimization of the two-step atomic layer etching process for HfO2 in conventional plasma etching tools were studied. The surface modification step was realized in Ar/CF4/H2 plasma, and the reaction between the modified layer and the surface was activated by Ar ion bombardment from the plasma in the second step. Investigation of the effects of activation step duration, DC bias during activation, and Ar plasma density was carried out. The mechanism of the etching process has been shown to involve fluorination of oxide during the modification step and subsequent removal of fluorine-containing particles at the activation step. An increase in parasitic sputtering rate and lower process saturation with the growth of DC bias during activation was demonstrated. The advantage of the ALE process in lower surface roughness over the conventional etching process was shown. Similar etching characteristics of HfO2 and ZrO2 suggest a similarity in the etching process for the mixed hafnium-zirconium oxide material.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"37 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141649165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Majer, S. Smink, W. Braun, Hongguang Wang, P. A. van Aken, J. Mannhart, F. Hensling
We have developed and optimized a method to grow ruthenium films of unprecedented quality. Our three-step process is reminiscent of solid-phase epitaxy. First, c-cut sapphire substrates are terminated at their Al-rich √31 × √31R ± 9° reconstruction by in situ annealing. Second, 3D structured epitaxial Ru films are deposited at low temperatures by laser evaporation of Ru rods. Third, the films, thus, obtained are epitaxially transformed by high-temperature annealing. X-ray diffraction studies reveal good crystallinity of the obtained 15–60 nm-thick films: peak widths of the rocking curve are one order of magnitude smaller than those of the best published films. Scanning transmission electron microscopy and electron energy loss studies show that the interface between the sapphire substrates and the flat Ru films is atomically sharp with very limited intermixing. These results demonstrate the usefulness of postanneal processes for producing high-quality epitaxial films of elemental metals on insulating substrates.
{"title":"Growth of high-quality ruthenium films on sapphire","authors":"L. Majer, S. Smink, W. Braun, Hongguang Wang, P. A. van Aken, J. Mannhart, F. Hensling","doi":"10.1116/6.0003756","DOIUrl":"https://doi.org/10.1116/6.0003756","url":null,"abstract":"We have developed and optimized a method to grow ruthenium films of unprecedented quality. Our three-step process is reminiscent of solid-phase epitaxy. First, c-cut sapphire substrates are terminated at their Al-rich √31 × √31R ± 9° reconstruction by in situ annealing. Second, 3D structured epitaxial Ru films are deposited at low temperatures by laser evaporation of Ru rods. Third, the films, thus, obtained are epitaxially transformed by high-temperature annealing. X-ray diffraction studies reveal good crystallinity of the obtained 15–60 nm-thick films: peak widths of the rocking curve are one order of magnitude smaller than those of the best published films. Scanning transmission electron microscopy and electron energy loss studies show that the interface between the sapphire substrates and the flat Ru films is atomically sharp with very limited intermixing. These results demonstrate the usefulness of postanneal processes for producing high-quality epitaxial films of elemental metals on insulating substrates.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141654863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fatima Jenina Arellano, Minoru Kusaba, Stephen Wu, Ryo Yoshida, Zoltán Donkó, Peter Hartmann, T. Tsankov, S. Hamaguchi
Optical emission spectroscopy (OES) is a highly valuable tool for plasma characterization due to its nonintrusive and versatile nature. The intensities of the emission lines contain information about the parameters of the underlying plasma–electron density ne and temperature or, more generally, the electron energy distribution function (EEDF). This study aims to obtain the EEDF and ne from the OES data of argon plasma with machine learning (ML) techniques. Two different models, i.e., the Kernel Regression for Functional Data (KRFD) and an artificial neural network (ANN), are used to predict the normalized EEDF and Random Forest (RF) regression is used to predict ne. The ML models are trained with computed plasma data obtained from Particle-in-Cell/Monte Carlo Collision simulations coupled with a collisional–radiative model. All three ML models developed in this study are found to predict with high accuracy what they are trained to predict when the simulated test OES data are used as the input data. When the experimentally measured OES data are used as the input data, the ANN-based model predicts the normalized EEDF with reasonable accuracy under the discharge conditions where the simulation data are known to agree well with the corresponding experimental data. However, the capabilities of the KRFD and RF models to predict the EEDF and ne from experimental OES data are found to be rather limited, reflecting the need for further improvement of the robustness of these models.
光学发射光谱（OES）具有非侵入性和多功能性的特点，是一种非常有价值的等离子体表征工具。发射线的强度包含基本等离子体参数的信息--电子密度 ne 和温度，或者更广泛地说，电子能量分布函数 (EEDF)。本研究旨在利用机器学习（ML）技术从氩等离子体的 OES 数据中获取 EEDF 和 ne。两种不同的模型，即函数数据核回归（KRFD）和人工神经网络（ANN），用于预测归一化 EEDF，随机森林（RF）回归用于预测 ne。ML 模型是利用从 "细胞内粒子"/"蒙特卡洛碰撞 "模拟中获得的计算等离子体数据以及碰撞辐射模型进行训练的。当模拟测试的 OES 数据作为输入数据时，本研究中开发的所有三个 ML 模型都能高精度地预测它们所训练预测的结果。当使用实验测量的 OES 数据作为输入数据时，在已知模拟数据与相应实验数据非常吻合的放电条件下，基于 ANN 的模型能以合理的精度预测归一化 EEDF。然而，KRFD 和 RF 模型根据实验 OES 数据预测 EEDF 和 ne 的能力相当有限，这反映出需要进一步提高这些模型的稳健性。
{"title":"Machine learning-based prediction of the electron energy distribution function and electron density of argon plasma from the optical emission spectra","authors":"Fatima Jenina Arellano, Minoru Kusaba, Stephen Wu, Ryo Yoshida, Zoltán Donkó, Peter Hartmann, T. Tsankov, S. Hamaguchi","doi":"10.1116/6.0003731","DOIUrl":"https://doi.org/10.1116/6.0003731","url":null,"abstract":"Optical emission spectroscopy (OES) is a highly valuable tool for plasma characterization due to its nonintrusive and versatile nature. The intensities of the emission lines contain information about the parameters of the underlying plasma–electron density ne and temperature or, more generally, the electron energy distribution function (EEDF). This study aims to obtain the EEDF and ne from the OES data of argon plasma with machine learning (ML) techniques. Two different models, i.e., the Kernel Regression for Functional Data (KRFD) and an artificial neural network (ANN), are used to predict the normalized EEDF and Random Forest (RF) regression is used to predict ne. The ML models are trained with computed plasma data obtained from Particle-in-Cell/Monte Carlo Collision simulations coupled with a collisional–radiative model. All three ML models developed in this study are found to predict with high accuracy what they are trained to predict when the simulated test OES data are used as the input data. When the experimentally measured OES data are used as the input data, the ANN-based model predicts the normalized EEDF with reasonable accuracy under the discharge conditions where the simulation data are known to agree well with the corresponding experimental data. However, the capabilities of the KRFD and RF models to predict the EEDF and ne from experimental OES data are found to be rather limited, reflecting the need for further improvement of the robustness of these models.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The predeformation prior to artificial aging plays an important role in enhancing the properties of Al–Cu–Li based alloys. This study focused on investigating the impact of a large amount of prerolling (20%) on the orientation variation and distribution characteristics of T1 precipitates in a rolled Al–Cu–Li alloy. The results revealed that T1 phases precipitated in the same orientation were not strictly parallel within a grain, a small angle existed between different phases in the same direction due to the orientation fluctuation of the matrix induced by prerolling. The misorientation degree of the T1 precipitates presented a slight expend tendency with increasing the aging time. Furthermore, the connection between this orientation distortion of the T1 phases and the tensile properties was discussed. Additionally, it was found that the T1 variants along different orientations were heterogeneously distributed, possibly due to the activation of different slip systems during the prerolling process and the variation in the number of nucleation sites among the nonparallel habit planes.
{"title":"Influence of pre-rolling deformation on distribution characteristics of T1 precipitate in artificially aged Al–Cu–Li alloy","authors":"Shuwei Duan, Fuqiang Guo, Wenting Ma, Zhongli Liu, Xiaoyang Yi, Kenji Matsuda, Yue Li, Yong Zou","doi":"10.1116/6.0003679","DOIUrl":"https://doi.org/10.1116/6.0003679","url":null,"abstract":"The predeformation prior to artificial aging plays an important role in enhancing the properties of Al–Cu–Li based alloys. This study focused on investigating the impact of a large amount of prerolling (20%) on the orientation variation and distribution characteristics of T1 precipitates in a rolled Al–Cu–Li alloy. The results revealed that T1 phases precipitated in the same orientation were not strictly parallel within a grain, a small angle existed between different phases in the same direction due to the orientation fluctuation of the matrix induced by prerolling. The misorientation degree of the T1 precipitates presented a slight expend tendency with increasing the aging time. Furthermore, the connection between this orientation distortion of the T1 phases and the tensile properties was discussed. Additionally, it was found that the T1 variants along different orientations were heterogeneously distributed, possibly due to the activation of different slip systems during the prerolling process and the variation in the number of nucleation sites among the nonparallel habit planes.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141660915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Patouillard, M. Bernard, S. Cadot, R. Gassilloud, N. Bernier, A. Grenier, A. Mantoux, E. Blanquet, F. Martin, C. Raynaud, F. Gianesello
Aluminum nitride (AlN) is a wide bandgap material used in acoustic devices, piezo- micro-electromechanical system and is promising for other electronic applications. However, for most applications, the AlN crystalline quality obtained by PVD or MOCVD is insufficient, and suitable growth substrates providing an adapted lattice match and coefficient of thermal expansion are limited. Alternatively, monocrystalline AlN wafers are not yet available in 200/300 mm sizes and suffer from high costs and quality issues. Here, we propose a novel approach involving a two-dimensional transition metal dichalcogenide (TMD) material as a seed layer, which displays an excellent lattice matching with AlN (>98%) allowing a strong enhancement in the c axis texture of sputtered AlN layers on Si(100)/SiO2 thermal oxide (500 nm) substrates. We have successfully demonstrated an eightfold improvement of the AlN (002) rocking curve compared to reference samples grown on thermal SiO2, thus providing a relevant and cost-effective process for the large-scale deployment of high-quality III-N materials on silicon-based substrates.
{"title":"MoS2-assisted growth of highly-oriented AlN thin films by low-temperature van der Waals epitaxy","authors":"J. Patouillard, M. Bernard, S. Cadot, R. Gassilloud, N. Bernier, A. Grenier, A. Mantoux, E. Blanquet, F. Martin, C. Raynaud, F. Gianesello","doi":"10.1116/6.0003652","DOIUrl":"https://doi.org/10.1116/6.0003652","url":null,"abstract":"Aluminum nitride (AlN) is a wide bandgap material used in acoustic devices, piezo- micro-electromechanical system and is promising for other electronic applications. However, for most applications, the AlN crystalline quality obtained by PVD or MOCVD is insufficient, and suitable growth substrates providing an adapted lattice match and coefficient of thermal expansion are limited. Alternatively, monocrystalline AlN wafers are not yet available in 200/300 mm sizes and suffer from high costs and quality issues. Here, we propose a novel approach involving a two-dimensional transition metal dichalcogenide (TMD) material as a seed layer, which displays an excellent lattice matching with AlN (>98%) allowing a strong enhancement in the c axis texture of sputtered AlN layers on Si(100)/SiO2 thermal oxide (500 nm) substrates. We have successfully demonstrated an eightfold improvement of the AlN (002) rocking curve compared to reference samples grown on thermal SiO2, thus providing a relevant and cost-effective process for the large-scale deployment of high-quality III-N materials on silicon-based substrates.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"85 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141662606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hsiao-Hsuan Wan, Chiao-Ching Chiang, Jian-Sian Li, N. Al-Mamun, Aman Haque, Fan Ren, S. Pearton
The dry etching of high crystal quality c-plane AlN grown by metal organic chemical vapor deposition was examined as a function of source and chuck power in inductively coupled plasmas of Cl2/Ar or Cl2/Ar/CHF3. Maximum etch rates of ∼1500 Å min−1 were obtained at high powers, with selectivity over SiO2 up to 3. The as-etched surfaces in Cl2/Ar/CHF3 have F-related residues, which can be removed in NH4OH solutions. The Al-polar basal plane was found to etch slowly in either KOH or H3PO4 liquid formulations with extensive formation of hexagonal etch pits related to dislocations. The activation energies for KOH- or H3PO4-based wet etching rates within these pits were 124 and 183 kJ/mol, respectively, which are indicative of reaction-limited etching.
{"title":"Dry and wet etching of single-crystal AlN","authors":"Hsiao-Hsuan Wan, Chiao-Ching Chiang, Jian-Sian Li, N. Al-Mamun, Aman Haque, Fan Ren, S. Pearton","doi":"10.1116/6.0003744","DOIUrl":"https://doi.org/10.1116/6.0003744","url":null,"abstract":"The dry etching of high crystal quality c-plane AlN grown by metal organic chemical vapor deposition was examined as a function of source and chuck power in inductively coupled plasmas of Cl2/Ar or Cl2/Ar/CHF3. Maximum etch rates of ∼1500 Å min−1 were obtained at high powers, with selectivity over SiO2 up to 3. The as-etched surfaces in Cl2/Ar/CHF3 have F-related residues, which can be removed in NH4OH solutions. The Al-polar basal plane was found to etch slowly in either KOH or H3PO4 liquid formulations with extensive formation of hexagonal etch pits related to dislocations. The activation energies for KOH- or H3PO4-based wet etching rates within these pits were 124 and 183 kJ/mol, respectively, which are indicative of reaction-limited etching.","PeriodicalId":170900,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"116 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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