{"title":"ToF-SIMS analysis of ultrathin films and their fragmentation patterns.","authors":"Shin Muramoto, Daniel J Graham, David G Castner","doi":"10.1116/6.0003249","DOIUrl":"10.1116/6.0003249","url":null,"abstract":"<p><p>Organic thin films are of great interest due to their intriguing interfacial and functional properties, especially for device applications such as thin-film transistors and sensors. As their thickness approaches single nanometer thickness, characterization and interpretation of the extracted data become increasingly complex. In this study, plasma polymerization is used to construct ultrathin films that range in thickness from 1 to 20 nm, and time-of-flight secondary ion mass spectrometry coupled with principal component analysis is used to investigate the effects of film thickness on the resulting spectra. We demonstrate that for these cross-linked plasma polymers, at these thicknesses, the observed trends are different from those obtained from thicker films with lower degrees of cross-linking: contributions from ambient carbon contamination start to dominate the mass spectrum; cluster-induced nonlinear enhancement in secondary ion yield is no longer observed; extent of fragmentation is higher due to confinement of the primary ion energy; and the size of the primary ion source also affects fragmentation (e.g., Bi<sub>1</sub> versus Bi<sub>5</sub>). These differences illustrate that care must be taken in choosing the correct primary ion source as well as in interpreting the data.</p>","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"42 2","pages":"023416"},"PeriodicalIF":2.9,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10846908/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139702854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spinel LiGa5O8 prospects as ultra-wideband-gap semiconductor: Band structure, optical properties, and doping","authors":"Walter R. L. Lambrecht","doi":"10.1116/6.0003117","DOIUrl":"https://doi.org/10.1116/6.0003117","url":null,"abstract":"LiGa5O8 in the spinel type structure is investigated as a potential ultra-wideband-gap semiconductor. The band structure is determined using the quasiparticle self-consistent GW method, and the optical properties are calculated at the Bethe Salpeter Equation level including electron-hole interaction effects. The optical gap including exciton effects and an estimate of the zero-point motion electron phonon coupling renormalizations is estimated to be about 5.2±0.1 eV with an exciton binding energy of about 0.4 eV. Si doping as potential n-type dopant is investigated and found to be a promising shallow donor.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"17 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taylor G. Smith, Ali M. Ali, Jean-François de Marneffe, Jane P. Chang
{"title":"Plasma nitridation for atomic layer etching of Ni","authors":"Taylor G. Smith, Ali M. Ali, Jean-François de Marneffe, Jane P. Chang","doi":"10.1116/6.0003263","DOIUrl":"https://doi.org/10.1116/6.0003263","url":null,"abstract":"Nickel (Ni) and its alloys are important multifunctional materials for the fabrication of integrated circuits, as either the absorber for the extreme ultraviolet lithography masks and/or interconnect metals at the nanometer scale. However, these applications require that Ni to be patterned controllably, selectively, and anisotropically—requirements that can only be met with a plasma based atomic layer etch (ALE) process. In this work, a plasma-thermal ALE approach is developed to pattern Ni, utilizing a nitrogen plasma to form NixN at the surface, formic acid (FA) vapor to selectively remove the NixN layer, and a low-energy Ar+ sputter process to remove carbon residue left by the FA prior to the subsequent nitridation step. This three step ALE process was shown effective to etch Ni with a rate of 1.3 ± 0.17 nm/cycle while maintaining surface smoothness.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"273 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dislocation avalanches in nanostructured molybdenum nanopillars","authors":"Haw-Wen Hsiao, Jia-Hong Huang, Jian-Min Zuo","doi":"10.1116/6.0003254","DOIUrl":"https://doi.org/10.1116/6.0003254","url":null,"abstract":"We investigate intermittent plasticity in nanopillars of nanocrystalline molybdenum based on in situ transmission electron microscopy observations. By correlating electron imaging results with the measured nanopillar mechanical response, we demonstrate that the intermittent plasticity in nanocrystalline molybdenum is largely caused by dislocation avalanches. Electron imaging further reveals three types of dislocation avalanches, from intragranular to transgranular to cross-granular avalanches. The measured strain bursts resulted from avalanches have similar magnitudes to those reported for the molybdenum single-crystal pillars, while the corresponding flow stress in nanocrystalline molybdenum is greatly enhanced by the small grain size. Statistical analysis also shows that the avalanches behavior has similar characteristic as single crystals in the mean field theory model. Together, our findings here provide critical insights into the deformation mechanisms in a nanostructured body-centered-cubic metal.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"39 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Kinetic Monte Carlo study on the effect of growth conditions on the epitaxial growth of 3C–SiC (0001) vicinal surface","authors":"Xuejiang Chen, Xinyao Zhang, Wensen Ai","doi":"10.1116/6.0003144","DOIUrl":"https://doi.org/10.1116/6.0003144","url":null,"abstract":"Due to the lack of research on the microscopic evolution process and the formation of step growth patterns for SiC crystals, it is of great importance to deepen the understanding of the epitaxial growth of a SiC vicinal surface from a microscopic point of view. In this study, a three-dimensional lattice kinetic Monte Carlo algorithm was used to study the step flow growth characteristics of SiC crystals. The microscopic evolution of the step flow growth patterns for SiC vicinal surfaces was shown. C and Si were treated as the basic particles, and the net deposition and diffusion of atoms were considered in this model. The periodic boundary conditions were applied along the step edge and the helical boundary conditions were applied in the direction perpendicular to the step. The surface morphology evolution of SiC crystals grown on step substrates was simulated at different growth temperatures, partial deposition fluxes, and terrace widths. The results indicated that the growth patterns of the SiC vicinal surface could be transformed from a step flow growth to a nucleation growth pattern by decreasing the growth temperature, increasing the deposition flux, and increasing the terrace width.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"25 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Cristea, A. I. Scărlătescu, G. Bulai, D. Martínez-Martínez, C. I. da Silva Oliveira, G. Yan, L. Cunha
{"title":"Hardness, adhesion, and wear behavior of magnetron cosputtered Ti:Zr-O-N thin films","authors":"D. Cristea, A. I. Scărlătescu, G. Bulai, D. Martínez-Martínez, C. I. da Silva Oliveira, G. Yan, L. Cunha","doi":"10.1116/6.0003267","DOIUrl":"https://doi.org/10.1116/6.0003267","url":null,"abstract":"Reactive magnetron sputtering was used to deposit Ti:Zr-O-N thin films, by using a single Zr target, with Ti ribbons placed on the erosion track of the Zr sputtering target. Zr-O-N thin films have been also deposited in the same chamber to be used as reference films. The number of Ti ribbons, the applied sputtering current, and the reactive gas flow were the variable parameters. The films were analyzed in terms of structural development and mechanical properties (instrumented indentation, adhesion scratch testing, and wear analysis). The films are either amorphous or composed of a mixture of crystalline phases based on zirconium and titanium oxides or nitrides. Hardness values are situated between ∼10 and 11 GPa for the reference films (deposited without Ti) and up to ∼22 GPa for one of the Ti:Zr-O-N films. The films deposited without Ti behave slightly better in terms of adhesion to the substrate in comparison to the remaining samples in relation to the occurrence of first cracks (Lc1, critical load 1) and for first delamination (Lc2, critical load 2), a phenomenon probably related to the lower hardness of these films, which can accommodate the plastic deformation caused by the diamond indenter, prior to the occurrence of delamination. Adhesion to the substrate is a critical characteristic during wear tests since some of the coatings exhibit severe delamination.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"11 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Atomic layer etching of indium tin oxide","authors":"Christoffer Kauppinen","doi":"10.1116/6.0003170","DOIUrl":"https://doi.org/10.1116/6.0003170","url":null,"abstract":"This work presents the atomic layer etching (ALE) process for sputtered indium tin oxide (ITO) thin films using thermal surface modification with BCl3 and modified surface removal by low ion energy Ar plasma. In this approach, an elevated temperature is required for high synergy ALE due to the low volatility of indium chlorides, and 150°C is proved to be suitable. An etch per cycle (EPC) of 1.1 Å and ALE synergy of 82% was achieved. Both surface modification and modified surface removal steps exhibited self-limited EPC. The ALE process was developed in a conventional reactive ion etching tool and retains the thin film absolute uniformity on the wafer. ITO was photolithographically patterned on whole wafers using photoresist as an etch mask for the ALE, and clear smoothing of the unmasked areas is observed, which is a characteristic of an ideal ALE process. This confirms that the developed ALE process can be utilized to pattern ITO using conventional photolithography. The demonstrated ITO ALE can be used to fabricate, for example, thin channel or recessed channel transistors, with self-smoothened channels for reduced surface scattering.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"63 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lars Freter, Liverios Lymperakis, Michael Schnedler, Holger Eisele, Lei Jin, Jianxun Liu, Qian Sun, Rafal E. Dunin-Borkowski, Philipp Ebert
{"title":"Composition dependence of intrinsic surface states and Fermi-level pinning at ternary AlxGa1−xN m-plane surfaces","authors":"Lars Freter, Liverios Lymperakis, Michael Schnedler, Holger Eisele, Lei Jin, Jianxun Liu, Qian Sun, Rafal E. Dunin-Borkowski, Philipp Ebert","doi":"10.1116/6.0003225","DOIUrl":"https://doi.org/10.1116/6.0003225","url":null,"abstract":"Growth on nonpolar group III-nitride semiconductor surfaces has been suggested to be a remedy for avoiding detrimental polarization effects. However, the presence of intrinsic surface states within the fundamental bandgap at nonpolar surfaces leads to a Fermi-level pinning during growth, affecting the incorporation of dopants and impurities. This is further complicated by the use of ternary, e.g., AlxGa1−xN layers in device structures. In order to quantify the Fermi-level pinning on ternary group III nitride nonpolar growth surface, the energy position of the group III-derived empty dangling bond surface state at nonpolar AlxGa1−xN(101¯0) surfaces is determined as a function of the Al concentration using cross-sectional scanning tunneling microscopy and spectroscopy. The measurements show that the minimum energy of the empty dangling bond state shifts linearly toward midgap for increasing Al concentration with a slope of ≈5 meV/%. These experimental findings are supported by complementary density functional theory calculations.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"54 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140057742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spatial distribution diagnosis of electron temperature and density of argon inductively coupled plasma by tomographic optical emission spectroscopic measurement and collisional-radiative model","authors":"Yuya Yamashita, Kenta Doi, Tetsuji Kiyota, Kenta Ishi, Shuhei Watanabe, Wataru Kikuchi, Atsushi Nezu, Hiroshi Akatsuka","doi":"10.1116/6.0003209","DOIUrl":"https://doi.org/10.1116/6.0003209","url":null,"abstract":"There are few reported cases in which the spatial distribution of spectral emission coefficients of plasmas from tomographic optical emission spectroscopy measurements is analyzed based on a collisional-radiative model to diagnose the spatial distribution electron temperature of Te and density Ne. This study aimed at in situ diagnosis of process plasma. The spectral radiance of 18 lines-of-sight was measured simultaneously in argon inductively coupled plasma. The spatial distribution of the excited level number density distribution was calculated from the spatial distribution of spectral emission coefficients obtained from spectral tomography calculations. The three-dimensional distribution of Te and Ne was analyzed using a collisional-radiative model from the obtained spatial distribution of the excited levels number density. The effects of power and pressure on the dependence of the spatial distribution of Te and Ne were discussed. Furthermore, data processing methods for spectral tomographic measurements with coarse wavelength resolution were also discussed.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"2014 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Per O. Å. Persson, Johanna Rosen, Ivan Petrov, Justinas Palisaitis
{"title":"Exploring the thermal behavior and diffusive functionality of structural defects and phase boundaries in near-stoichiometric chromium diborides by in situ scanning transmission electron microscopy","authors":"Per O. Å. Persson, Johanna Rosen, Ivan Petrov, Justinas Palisaitis","doi":"10.1116/6.0003389","DOIUrl":"https://doi.org/10.1116/6.0003389","url":null,"abstract":"Near-stoichiometric chromium diboride films were subject to in situ annealing inside a scanning transmission electron microscope to access the thermal behavior of the film and embedded structural planar defects. Independent of films’ stoichiometry, the planar defects were unaffected by the applied heat treatments. On the contrary, the interfaces between the boron-rich tissue phase and the CrB2 phase were reshaped in the overstoichometric CrB2 film. At high temperatures, diffusion of contact metal species (platinum) from the focused ion beam sample preparation was triggered, with subsequent migration onto the sample. This resulted in the formation of metal-rich regions as directly observed and characterized at the atomic level. We determined that platinum did not react with the diboride structure but is accommodated by various defects present in the film.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"66 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}