{"title":"Scanning electron microscopy imaging of multilayer-doped GaN: Effects of surface band bending, surface roughness, and contamination layers on doping contrast","authors":"Siyuan Wang, Kai Zhang, Le Zhai, Li Huang","doi":"10.1116/6.0003824","DOIUrl":"https://doi.org/10.1116/6.0003824","url":null,"abstract":"Dopant profiling by a scanning electron microscope possesses great potential in the semiconductor industry due to its rapid, contactless, non-destructive, low cost, high spatial resolution, and high accuracy characteristics. Here, the influence of plasma and wet chemical treatments on doping contrast was investigated for a multilayered p-n GaN specimen, which is one of the most promising third-generation wide bandgap semiconductors. Angle-resolved x-ray photoelectron spectroscopy and atomic force microscope were employed to characterize the degree of surface band bending, surface roughness, gallium oxides, and hydrocarbons on the surface of GaN. N2 and air plasmas were unable to remove the surface contamination layers, although the degree of surface band bending was suppressed. In contrast, wet chemical methods offer superior capability in removing contamination layers; however, the surface roughness was increased to varying degrees. Notably, NH4F solution is capable of improving the doping contrast. The underlying mechanism was elucidated from the perspective of surface band bending, surface roughness, and contamination. The findings reported here will provide a feasible solution for effective characterization of semiconductor materials and devices.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"42 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147899729","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":"Insights into the genesis of oxygen vacancies and atomically dispersed Niδ− species in anatase TiO2: A spectroscopic study","authors":"Xiaoqiang Zhang, Yuteng Feng, Wei Zhang, Changhui Liang, Huixiang Li, Yongxin Li, Z. Conrad Zhang","doi":"10.1116/6.0003969","DOIUrl":"https://doi.org/10.1116/6.0003969","url":null,"abstract":"Oxygen vacancies are commonly observed defects in metal oxides that contribute to the unique physiochemical properties of these materials. Despite the abundant evidence of oxygen vacancies in transition metal oxides and their intriguing properties in catalysis, there remain questions in understanding their formation, structure, and properties. In this study, we employ in situ diffuse reflectance infrared Fourier transform spectroscopy and electron paramagnetic resonance spectroscopy to investigate the genesis of oxygen vacancies and Ni species, focusing on the significance of Ni species relating to the reduction temperature. Our findings reveal a reduction temperature dependence on the formation of oxygen vacancies and atomically dispersed Niδ− species in anatase TiO2 (TiO2-A). In pristine TiO2-A, the reduction temperature between 300 and 400 °C led to the creation of a substantial number of oxygen vacancies. With supported Ni on TiO2-A, oxygen vacancies are favorably formed at 200 °C. As the reduction temperature is increased to 300 °C, Ni species migrate to the oxygen vacancies and become stabilized by forming Niδ− species while reducing the number of oxygen vacancies. Subsequent oxidation at 300 °C led to the oxidation of some Niδ− species alongside the liberation of the oxygen vacancies they previously occupied. These findings shed light on the mechanisms in forming oxygen vacancies and Niδ− species.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"42 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147905979","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}
Eryan Gu, Yan Jin, Boxuan Li, Huilong Zhou, Zhuhui Lu, Yanwei Wen, Kun Cao, Rong Chen
{"title":"Effect of Al precursor’s properties on interactions with self-assembled monolayers for area selective deposition","authors":"Eryan Gu, Yan Jin, Boxuan Li, Huilong Zhou, Zhuhui Lu, Yanwei Wen, Kun Cao, Rong Chen","doi":"10.1116/6.0003847","DOIUrl":"https://doi.org/10.1116/6.0003847","url":null,"abstract":"Area selective deposition (ASD) is a high-precision atomic-level manufacturing technology that enables the development of bottom-up manufacturing methods in the future semiconductor field. The area selective deposition behavior of Al precursors on 1-octadecylthiol (ODT) passivated Cu/SiO2 surfaces was studied through experimental and theoretical analysis. The relationship between precursor steric hindrance, symmetry, penetration depth in ODT, and adsorption energy was elucidated. The loss of selectivity caused by different penetration depths of the precursor in ODT can be post-treated with acids or H2 plasma to remove the physisorption of precursor molecules between ODT chains, thereby improving the selectivity. Reliable ASD technology has been successfully applied to Cu/SiO2 patterns. Dimethylaluminum isopropoxide can selectively deposit about 10 nm of Al2O3 on SiO2 without detectable defects on the Cu area. This provides important insights into the choice of precursors in the ASD process and can extend its application to a wider range of device manufacturing schemes.","PeriodicalId":17490,"journal":{"name":"Journal of Vacuum Science & Technology A","volume":"42 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147902731","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":"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":2.4,"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}