During the etching of the dielectric layer of semiconductors through plasma etching, numerous flake particles are generated in the etching equipment. These particles cause layout defects on the wafer and engender reduced yield on production lines. Accordingly, this study investigated how such flake particles could form in a chamber involving varying levels of deterioration on the electrostatic chuck surface and varying levels of by-product deposition. Moreover, we tested the effect of various electrostatic chuck discharge sequences and voltages on the deposition of these flake particles. Our experimental results revealed that selecting an appropriate radiofrequency power and a voltage discharge sequence protocol for the electrostatic chuck and using a low-frequency radiofrequency power supply could minimize the number of flake particles adhering to a wafer surface. In the proposed method, wafer contamination is controlled by suppressing unstable electric stress that arises when the etching chamber is coated with deposited by-products and the electrostatic chuck has a deteriorated surface.
{"title":"Modification of discharge sequences to control the random dispersion of flake particles during wafer etching","authors":"Ching Ming Ku, Wen Yea Jang, Stone Cheng","doi":"10.1116/6.0002974","DOIUrl":"https://doi.org/10.1116/6.0002974","url":null,"abstract":"During the etching of the dielectric layer of semiconductors through plasma etching, numerous flake particles are generated in the etching equipment. These particles cause layout defects on the wafer and engender reduced yield on production lines. Accordingly, this study investigated how such flake particles could form in a chamber involving varying levels of deterioration on the electrostatic chuck surface and varying levels of by-product deposition. Moreover, we tested the effect of various electrostatic chuck discharge sequences and voltages on the deposition of these flake particles. Our experimental results revealed that selecting an appropriate radiofrequency power and a voltage discharge sequence protocol for the electrostatic chuck and using a low-frequency radiofrequency power supply could minimize the number of flake particles adhering to a wafer surface. In the proposed method, wafer contamination is controlled by suppressing unstable electric stress that arises when the etching chamber is coated with deposited by-products and the electrostatic chuck has a deteriorated surface.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134954748","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 interfacial reactivity at the Co/CuO interfaces has been investigated in situ by the technique of x-ray photoelectron spectroscopy. Thin films of cobalt were evaporated on the CuO substrates by the technique of e-beam. The depositions were undertaken by maintaining the substrates at ambient temperature. Significant differences have been observed in the Cu 2p core level spectra recorded for these samples and that for pure CuO. The Co 2p core level spectrum also shows differences upon comparison with the spectrum for elemental cobalt. These differences arise from chemical interaction occurring at the Co/CuO interface. The curve fitting technique has been utilized to estimate the relative percentages of the constituents at the interface. The interface width has been determined from the relative percentage of the unoxidized cobalt present in the overlayer. The dependence of the interface width has also been explored as a function of annealing temperature. The interface width is much less for the room temperature deposited sample as compared to that for annealed samples. The spectral data also indicate increase in the diffusion of copper oxide through the cobalt overlayer with increasing temperature.
{"title":"Interfacial reactivity in the Co/CuO samples as investigated by x-ray photoelectron spectroscopy","authors":"A. R. Chourasia, D. R. Chopra","doi":"10.1116/6.0002922","DOIUrl":"https://doi.org/10.1116/6.0002922","url":null,"abstract":"The interfacial reactivity at the Co/CuO interfaces has been investigated in situ by the technique of x-ray photoelectron spectroscopy. Thin films of cobalt were evaporated on the CuO substrates by the technique of e-beam. The depositions were undertaken by maintaining the substrates at ambient temperature. Significant differences have been observed in the Cu 2p core level spectra recorded for these samples and that for pure CuO. The Co 2p core level spectrum also shows differences upon comparison with the spectrum for elemental cobalt. These differences arise from chemical interaction occurring at the Co/CuO interface. The curve fitting technique has been utilized to estimate the relative percentages of the constituents at the interface. The interface width has been determined from the relative percentage of the unoxidized cobalt present in the overlayer. The dependence of the interface width has also been explored as a function of annealing temperature. The interface width is much less for the room temperature deposited sample as compared to that for annealed samples. The spectral data also indicate increase in the diffusion of copper oxide through the cobalt overlayer with increasing temperature.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134954216","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}
Chao-Ching Chiang, Hsiao-Hsuan Wan, Jian-Sian Li, Fan Ren, Timothy Jinsoo Yoo, Honggyu Kim, S. J. Pearton
Sputtered p-NiO films were used to suppress gate leakage and produce a positive shift in the gate voltage of AlGaN/GaN high-electron mobility transistors for e-mode operation. A direct comparison with Schottky-gated devices fabricated on the same wafer shows the utility of the NiO in increasing the on-off ratio and shifting the threshold voltage from −0.95 V (Schottky gated) to +0.9 V (NiO gated). The breakdown voltage was 780 V for a 40 μm drain-source separation. The subthreshold swing decreased from 181 mV/dec for Schottky-gated HEMTs to 128 mV/dec on NiO-gated devices. The simple fabrication process without any annealing or passivation steps shows the promise of NiO gates for e-mode AlGaN/GaN HEMT operation.
溅射p-NiO薄膜用于抑制栅极泄漏，并使AlGaN/GaN高电子迁移率晶体管的栅极电压产生正位移，从而实现电子模式工作。与同一晶圆上制造的肖特基门控器件的直接比较表明，NiO在提高通断比和将阈值电压从- 0.95 V(肖特基门控)转移到+0.9 V (NiO门控)方面的实用性。在40 μm漏源分离下，击穿电压为780 V。亚阈值摆幅从肖特基门控hemt的181 mV/dec降至nio门控器件的128 mV/dec。简单的制造工艺无需任何退火或钝化步骤，显示了用于e模AlGaN/GaN HEMT操作的NiO栅极的前景。
{"title":"E-mode AlGaN/GaN HEMTs using p-NiO gates","authors":"Chao-Ching Chiang, Hsiao-Hsuan Wan, Jian-Sian Li, Fan Ren, Timothy Jinsoo Yoo, Honggyu Kim, S. J. Pearton","doi":"10.1116/6.0003119","DOIUrl":"https://doi.org/10.1116/6.0003119","url":null,"abstract":"Sputtered p-NiO films were used to suppress gate leakage and produce a positive shift in the gate voltage of AlGaN/GaN high-electron mobility transistors for e-mode operation. A direct comparison with Schottky-gated devices fabricated on the same wafer shows the utility of the NiO in increasing the on-off ratio and shifting the threshold voltage from −0.95 V (Schottky gated) to +0.9 V (NiO gated). The breakdown voltage was 780 V for a 40 μm drain-source separation. The subthreshold swing decreased from 181 mV/dec for Schottky-gated HEMTs to 128 mV/dec on NiO-gated devices. The simple fabrication process without any annealing or passivation steps shows the promise of NiO gates for e-mode AlGaN/GaN HEMT operation.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135390951","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}
Qingzhi Shi, Sihui Wang, Pengcheng Wang, Yongsheng Ma, Biao Tan, Shiyuan Shi, Tao Huang, Tao Huang, Fei Sun, Lixin Wang, Xiaoguang Zhao, Shuping Chen, Meitong Lu
Non-evaporable getter (NEG) films are widely used in high vacuum technologies and have played a critical role in applications requiring ultrahigh vacuum conditions, such as accelerator vacuum systems. The passivation layers on the film surface due to air exposure generally require thermal vacuum activation. This research aims to elucidate the key factor in the activation of TiZrV NEG films from the perspective of atomic-scale microstructures. The characteristics of film element distributions, morphologies, and crystalline states before and after activation were investigated by energy dispersive spectroscopy, scanning electron microscopy, and grazing incidence x-ray diffraction. In situ x-ray photoelectron spectroscopy was used to detect compositional variations in the film surface layer at different activation temperatures. According to the analysis, from an atomic-scale perspective, the easily activated structures would degrade in activation performance when surrounded by structures that are difficult to activate. During activation, the activated structures tend to act as channels for foreign atoms until the surrounding structures are fully activated. Hydroxyl and carbonyl groups are generally easier to activate than hydrocarbons and surface carbides, but even groups of the same type vary greatly in activation difficulty due to the differences in atomic-scale microstructures on the film surface. These findings provide valuable insight into the activation of NEG films and may be beneficial in the design of novel NEG films with excellent activation performance.
{"title":"Effect of atomic-scale microstructures on TiZrV non-evaporable getter film activation","authors":"Qingzhi Shi, Sihui Wang, Pengcheng Wang, Yongsheng Ma, Biao Tan, Shiyuan Shi, Tao Huang, Tao Huang, Fei Sun, Lixin Wang, Xiaoguang Zhao, Shuping Chen, Meitong Lu","doi":"10.1116/6.0002992","DOIUrl":"https://doi.org/10.1116/6.0002992","url":null,"abstract":"Non-evaporable getter (NEG) films are widely used in high vacuum technologies and have played a critical role in applications requiring ultrahigh vacuum conditions, such as accelerator vacuum systems. The passivation layers on the film surface due to air exposure generally require thermal vacuum activation. This research aims to elucidate the key factor in the activation of TiZrV NEG films from the perspective of atomic-scale microstructures. The characteristics of film element distributions, morphologies, and crystalline states before and after activation were investigated by energy dispersive spectroscopy, scanning electron microscopy, and grazing incidence x-ray diffraction. In situ x-ray photoelectron spectroscopy was used to detect compositional variations in the film surface layer at different activation temperatures. According to the analysis, from an atomic-scale perspective, the easily activated structures would degrade in activation performance when surrounded by structures that are difficult to activate. During activation, the activated structures tend to act as channels for foreign atoms until the surrounding structures are fully activated. Hydroxyl and carbonyl groups are generally easier to activate than hydrocarbons and surface carbides, but even groups of the same type vary greatly in activation difficulty due to the differences in atomic-scale microstructures on the film surface. These findings provide valuable insight into the activation of NEG films and may be beneficial in the design of novel NEG films with excellent activation performance.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135390312","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}
One main obstacle to obtaining high carrier mobility in transistors with metal-oxide-semiconductor (MOS) structures is carrier scattering, which has been systematically investigated. In the past few decades, much attention was preferentially paid to the scatterings arising from the region near the semiconductor/oxide interface because they can affect the carrier transport in the semiconductor channel more directly and effectively, e.g., polaronic effect, Coulomb scattering, surface-roughness scattering, and intrinsic phonon scattering resulted from the thermal vibration of the semiconductor channel. However, scattering originated from hybrid interface plasmon/optical-phonon excitations, so-called remote phonon scattering, has been neglected to some extent, but is especially severe for gate oxides with high dielectric constants due to the easy vibrations of their atoms. On the other hand, plasmons generated from the oscillations of majority carriers in the gate electrode can couple with the remote phonons to suppress the remote phonon scattering, which is called the gate screening effect. However, when the frequency of the gate-electrode plasmon is close/equal to that of the gate-dielectric phonon, the resonance between the gate electrode and the gate dielectric greatly enhances the remote phonon scattering to severely degrade the carrier mobility (so-called gate antiscreening effect). This work intends to give a comprehensive review on the origins, effects, suppression methods, and recent advances of the remote phonon scattering, with a view to achieving high-mobility MOS devices (including those based on two-dimensional semiconductors) with high-k gate dielectrics for future high-speed electronic applications.
{"title":"Review on remote phonon scattering in transistors with metal-oxide-semiconductor structures adopting high-k gate dielectrics","authors":"Yuan Xiao Ma, Hui Su, Wing Man Tang, Pui To Lai","doi":"10.1116/5.0156557","DOIUrl":"https://doi.org/10.1116/5.0156557","url":null,"abstract":"One main obstacle to obtaining high carrier mobility in transistors with metal-oxide-semiconductor (MOS) structures is carrier scattering, which has been systematically investigated. In the past few decades, much attention was preferentially paid to the scatterings arising from the region near the semiconductor/oxide interface because they can affect the carrier transport in the semiconductor channel more directly and effectively, e.g., polaronic effect, Coulomb scattering, surface-roughness scattering, and intrinsic phonon scattering resulted from the thermal vibration of the semiconductor channel. However, scattering originated from hybrid interface plasmon/optical-phonon excitations, so-called remote phonon scattering, has been neglected to some extent, but is especially severe for gate oxides with high dielectric constants due to the easy vibrations of their atoms. On the other hand, plasmons generated from the oscillations of majority carriers in the gate electrode can couple with the remote phonons to suppress the remote phonon scattering, which is called the gate screening effect. However, when the frequency of the gate-electrode plasmon is close/equal to that of the gate-dielectric phonon, the resonance between the gate electrode and the gate dielectric greatly enhances the remote phonon scattering to severely degrade the carrier mobility (so-called gate antiscreening effect). This work intends to give a comprehensive review on the origins, effects, suppression methods, and recent advances of the remote phonon scattering, with a view to achieving high-mobility MOS devices (including those based on two-dimensional semiconductors) with high-k gate dielectrics for future high-speed electronic applications.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135972673","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}
Metalorganic chemical vapor deposition (MOCVD) epitaxial materials technology for the growth of compound semiconductors has been developed over the past 60-plus years to become the dominant process for both research and production of light-emitting devices as well as many other electronic and optoelectronic devices. Today, MOCVD has become the “Swiss Army Knife” of semiconductor epitaxial growth, covering a wide variety of compound semiconductors and device applications. Because of the flexibility and control offered by this process and the material quality produced by MOCVD, many important III–V semiconductor devices have become commercially viable. This paper attempts to provide a personal view of the early development of MOCVD and some brief historical discussion of this important and highly versatile materials technology for the growth of high-quality devices employing ultrathin layers and heterojunctions of III–V compound semiconductors, e.g., quantum-well lasers, light-emitting diodes, heterojunction solar cells, transistors, and photonic integrated circuits.
{"title":"III–V semiconductor devices grown by metalorganic chemical vapor deposition—The development of the Swiss Army Knife for semiconductor epitaxial growth","authors":"Russell D. Dupuis","doi":"10.1116/6.0003062","DOIUrl":"https://doi.org/10.1116/6.0003062","url":null,"abstract":"Metalorganic chemical vapor deposition (MOCVD) epitaxial materials technology for the growth of compound semiconductors has been developed over the past 60-plus years to become the dominant process for both research and production of light-emitting devices as well as many other electronic and optoelectronic devices. Today, MOCVD has become the “Swiss Army Knife” of semiconductor epitaxial growth, covering a wide variety of compound semiconductors and device applications. Because of the flexibility and control offered by this process and the material quality produced by MOCVD, many important III–V semiconductor devices have become commercially viable. This paper attempts to provide a personal view of the early development of MOCVD and some brief historical discussion of this important and highly versatile materials technology for the growth of high-quality devices employing ultrathin layers and heterojunctions of III–V compound semiconductors, e.g., quantum-well lasers, light-emitting diodes, heterojunction solar cells, transistors, and photonic integrated circuits.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135813954","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}
Lithography is one of the key steps in micro/nanofabrication, which involves the use of oil-based resists, organic solvents, and toxic chemicals. Nowadays, environmental issues and regulation have raised the need for developing greener materials and processes. Therefore, efforts have been devoted to developing greener resists, in particular, resists based on water-soluble bio-sourced polymers. Among these biopolymers, polysaccharides have gained a strong interest. However, their interaction with silica etching plasmas, in particular, fluorinated plasmas, remains scarcely studied and contradictory results are found in the literature. The present contribution reports on the study of the interaction of two chitosans exhibiting different degrees of N-acetylation with SF6/Ar and CHF3 etching plasmas. The surface modifications and in-depth modifications were studied with x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, infrared spectroscopy, water contact angle, and size-exclusion chromatography. The effect of neutrals, ions, and vacuum ultraviolet (VUV) was considered. Our results suggest that the chitosan selectivity is greatly influenced by the deposition of a fluorocarbon film and that VUV seems to be involved in scissions of the polymer chains. No significant difference between the two chitosans was observed.
{"title":"Water-soluble bio-sourced resist interactions with fluorinated etching plasmas during the photolithography process","authors":"Paule Durin, Olha Sysova, Alexandre Téolis, Stéphane Trombotto, Samar Hajjar-Garreau, Thierry Delair, Isabelle Servin, Névine Rochat, Raluca Tiron, Corinne Gablin, Olivier Soppera, Aziz Benamrouche, Thomas Géhin, Didier Léonard, Jean-Louis Leclercq, Yann Chevolot","doi":"10.1116/6.0002934","DOIUrl":"https://doi.org/10.1116/6.0002934","url":null,"abstract":"Lithography is one of the key steps in micro/nanofabrication, which involves the use of oil-based resists, organic solvents, and toxic chemicals. Nowadays, environmental issues and regulation have raised the need for developing greener materials and processes. Therefore, efforts have been devoted to developing greener resists, in particular, resists based on water-soluble bio-sourced polymers. Among these biopolymers, polysaccharides have gained a strong interest. However, their interaction with silica etching plasmas, in particular, fluorinated plasmas, remains scarcely studied and contradictory results are found in the literature. The present contribution reports on the study of the interaction of two chitosans exhibiting different degrees of N-acetylation with SF6/Ar and CHF3 etching plasmas. The surface modifications and in-depth modifications were studied with x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, infrared spectroscopy, water contact angle, and size-exclusion chromatography. The effect of neutrals, ions, and vacuum ultraviolet (VUV) was considered. Our results suggest that the chitosan selectivity is greatly influenced by the deposition of a fluorocarbon film and that VUV seems to be involved in scissions of the polymer chains. No significant difference between the two chitosans was observed.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135863981","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}
Adam R. Thomas, Naresh B. Kotadiya, Binyu Wang, Tara P. Dhakal
This paper presents fast, accurate software for modeling physical vapor deposition systems over irregular surfaces. The model is implemented using graphics processing unit (GPU) ray casting. Applied models are viewed as a cross section of the area of interest. Given evaporation rate, time, and angular profiles in a vacuum system, an iterative time-step approach for calculating deposition profiles is calculated in the GPU architecture following a ballistic modeling approach. Thin-film technologies for the electronics industry will require evaporations on complex surfaces. Depending on the nature of the surface, a uniform thin film across the topology is wanted for various device parameters. The ray casting method is tested against various profiles. The code is freely distributed on GitHub (see https://github.com/adam-r-thomas/PVDS).
{"title":"Physical vapor deposition simulator by graphical processor unit ray casting","authors":"Adam R. Thomas, Naresh B. Kotadiya, Binyu Wang, Tara P. Dhakal","doi":"10.1116/6.0003045","DOIUrl":"https://doi.org/10.1116/6.0003045","url":null,"abstract":"This paper presents fast, accurate software for modeling physical vapor deposition systems over irregular surfaces. The model is implemented using graphics processing unit (GPU) ray casting. Applied models are viewed as a cross section of the area of interest. Given evaporation rate, time, and angular profiles in a vacuum system, an iterative time-step approach for calculating deposition profiles is calculated in the GPU architecture following a ballistic modeling approach. Thin-film technologies for the electronics industry will require evaporations on complex surfaces. Depending on the nature of the surface, a uniform thin film across the topology is wanted for various device parameters. The ray casting method is tested against various profiles. The code is freely distributed on GitHub (see https://github.com/adam-r-thomas/PVDS).","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135863440","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}
In this work, we demonstrate that the permeability of a SiNx thin film (prepared by plasma-enhanced chemical vapor deposition) to water and oxygen is closely related to the deposition pressure. By dynamic secondary ion mass spectrometry, we confirmed that water penetration occurs into the SiNx film only in the oxidized layer. Furthermore, positron annihilation lifetime spectroscopy indicated that a SiNx film with a lower deposition pressure provides a smaller pore (free volume hole) radius, which is more effective in terms of blocking ambient molecular diffusion or penetration. The SiNx films were also applied as an encapsulation layer for organic light-emitting diodes; SiNx films with a lower deposition pressure exhibited higher encapsulation properties.
{"title":"Permeation of oxygen and water into a plasma-enhanced chemical vapor deposited silicon nitride film as function of deposition pressure","authors":"Masayuki Shiochi, Hiroshi Fujimoto, Hin Wai Mo, Keiko Inoue, Yusaku Tanahashi, Hiroyuki Hosomi, Takashi Miyamoto, Hiroshi Miyazaki, Chihaya Adachi","doi":"10.1116/6.0003050","DOIUrl":"https://doi.org/10.1116/6.0003050","url":null,"abstract":"In this work, we demonstrate that the permeability of a SiNx thin film (prepared by plasma-enhanced chemical vapor deposition) to water and oxygen is closely related to the deposition pressure. By dynamic secondary ion mass spectrometry, we confirmed that water penetration occurs into the SiNx film only in the oxidized layer. Furthermore, positron annihilation lifetime spectroscopy indicated that a SiNx film with a lower deposition pressure provides a smaller pore (free volume hole) radius, which is more effective in terms of blocking ambient molecular diffusion or penetration. The SiNx films were also applied as an encapsulation layer for organic light-emitting diodes; SiNx films with a lower deposition pressure exhibited higher encapsulation properties.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870571","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}
Pallavi Saha, Eric Montgomery, Shashi Poddar, Oksana Chubenko, Siddharth Karkare
We report on the novel use of a Cs+ ion gun for an ion-beam-assisted molecular-beam-epitaxy (IBA-MBE) method to sequentially deposit Cs-Sb cathodes on room temperature substrates as opposed to the standard technique of thermal evaporation on elevated-temperature substrates. The details of the ultrahigh-vacuum chamber, the Cs+ ion source, and the growth technique are elaborated. The final quantum efficiency (QE) is reasonably good for Cs-Sb cathodes grown on two different substrates—Si (100) and strontium titanate—and is comparable to the QE of cathodes grown using thermal sources. This suggests that IBA-MBE could be a viable alternative to grow alkali-antimonides without substrate heating, paving the way for the growth of epitaxial alkali-antimonides in a more reproducible fashion, which may help improve the efficiency of photon detectors and accelerator applications that use alkali-antimonides as electron sources.
{"title":"Ion-beam-assisted growth of cesium-antimonide photocathodes","authors":"Pallavi Saha, Eric Montgomery, Shashi Poddar, Oksana Chubenko, Siddharth Karkare","doi":"10.1116/6.0002909","DOIUrl":"https://doi.org/10.1116/6.0002909","url":null,"abstract":"We report on the novel use of a Cs+ ion gun for an ion-beam-assisted molecular-beam-epitaxy (IBA-MBE) method to sequentially deposit Cs-Sb cathodes on room temperature substrates as opposed to the standard technique of thermal evaporation on elevated-temperature substrates. The details of the ultrahigh-vacuum chamber, the Cs+ ion source, and the growth technique are elaborated. The final quantum efficiency (QE) is reasonably good for Cs-Sb cathodes grown on two different substrates—Si (100) and strontium titanate—and is comparable to the QE of cathodes grown using thermal sources. This suggests that IBA-MBE could be a viable alternative to grow alkali-antimonides without substrate heating, paving the way for the growth of epitaxial alkali-antimonides in a more reproducible fashion, which may help improve the efficiency of photon detectors and accelerator applications that use alkali-antimonides as electron sources.","PeriodicalId":17571,"journal":{"name":"Journal of Vacuum Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136261698","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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