G. Sombrio, Emerson Oliveira, J. Strassner, Christoph Doering, H. Fouckhardt
Semiconductor multilayer and device fabrication is a complex task in electronics and opto-electronics. Layer dry etching is one of the process steps to achieve a specific lateral device design. In situ and real-time monitoring of etch depth will be necessary if high precision in etch depth is required. Nondestructive optical techniques are the methods of choice. Reflectance anisotropy spectroscopy equipment has been used to monitor the accurate etch depth during reactive ion etching of III/V semiconductor samples in situ and real time. For this purpose, temporal Fabry–Perot oscillations due to the etch-related shrinking thickness of the uppermost layer have been exploited. Earlier, we have already reported an etch-depth resolution of ±16.0 nm. By the use of a quadruple-Vernier-scale measurement and an evaluation protocol, now we even improve the in situ real-time etch-depth resolution by a factor of 20, i.e., nominally down to ±0.8 nm.
{"title":"Interferometric in-situ III/V semiconductor dry-etch depth-control with ±0.8 nm best accuracy using a quadruple-Vernier-scale measurement","authors":"G. Sombrio, Emerson Oliveira, J. Strassner, Christoph Doering, H. Fouckhardt","doi":"10.1116/6.0001209","DOIUrl":"https://doi.org/10.1116/6.0001209","url":null,"abstract":"Semiconductor multilayer and device fabrication is a complex task in electronics and opto-electronics. Layer dry etching is one of the process steps to achieve a specific lateral device design. In situ and real-time monitoring of etch depth will be necessary if high precision in etch depth is required. Nondestructive optical techniques are the methods of choice. Reflectance anisotropy spectroscopy equipment has been used to monitor the accurate etch depth during reactive ion etching of III/V semiconductor samples in situ and real time. For this purpose, temporal Fabry–Perot oscillations due to the etch-related shrinking thickness of the uppermost layer have been exploited. Earlier, we have already reported an etch-depth resolution of ±16.0 nm. By the use of a quadruple-Vernier-scale measurement and an evaluation protocol, now we even improve the in situ real-time etch-depth resolution by a factor of 20, i.e., nominally down to ±0.8 nm.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"99 1","pages":"052204"},"PeriodicalIF":0.0,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85779826","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}
Michael Barrow, Shawn Wright, Sarah Puzycki, P. Shah, R. Bedford, Yuanchang Zhang, J. Phillips
Selective etching of GaAs is critical for many applications, including flat optical components and high electron mobility transistors. It is long-known that F-containing process gases produce a nonvolatile AlF x layer on AlGaAs. In this work, we present a selective GaAs etch using an inductively coupled plasma with an HBr/SF 6/He etch chemistry. The optimized process exhibits >1μm/min etch rates, >200:1 GaAs:AlGaAs selectivity, >50:1 GaAs:photoresist selectivity, sub-nm surface roughness, and minimal undercut. The effect of aspect ratio is investigated, revealing limitations for deposition of an Si-rich passivation layer. Moreover, selectivity dramatically increases with an AlGaAs etch stop with high (90%) Al content. By characterizing an HBr-based selective GaAs etch, this work provides a possible alternative to the better established chlorine-based selective processes.
{"title":"Highly selective GaAs/AlGaAs dry etching using HBr/SF6/He","authors":"Michael Barrow, Shawn Wright, Sarah Puzycki, P. Shah, R. Bedford, Yuanchang Zhang, J. Phillips","doi":"10.1116/6.0001181","DOIUrl":"https://doi.org/10.1116/6.0001181","url":null,"abstract":"Selective etching of GaAs is critical for many applications, including flat optical components and high electron mobility transistors. It is long-known that F-containing process gases produce a nonvolatile AlF x layer on AlGaAs. In this work, we present a selective GaAs etch using an inductively coupled plasma with an HBr/SF 6/He etch chemistry. The optimized process exhibits >1μm/min etch rates, >200:1 GaAs:AlGaAs selectivity, >50:1 GaAs:photoresist selectivity, sub-nm surface roughness, and minimal undercut. The effect of aspect ratio is investigated, revealing limitations for deposition of an Si-rich passivation layer. Moreover, selectivity dramatically increases with an AlGaAs etch stop with high (90%) Al content. By characterizing an HBr-based selective GaAs etch, this work provides a possible alternative to the better established chlorine-based selective processes.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"23 1","pages":"052202"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81917116","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}
Toshiya Hamasaki, K. Yagyu, H. Mitani, T. Nishida, H. Tochihara, Takayuki Suzuki
Hydrogen etching of a 4H-SiC(0001) surface at a moderate temperature of 1200 °C with molecular hydrogen gas was investigated to obtain enough flat and clean surface for large-scale high-quality epitaxial graphene synthesis. We found after a prolonged hydrogen etching that micro scratches, large depressions, and contaminations produced on the wafer in the manufacturing process disappeared and that a periodic array of atomic steps appeared, maintaining initial flat surface morphology. One hour of etching with a flow of 1.0 l/min was the optimum condition to obtain a flat and clean SiC surface in the present study. Using such surfaces, we were able to synthesize the so-called zero layer graphene by thermal annealing in ultrahigh vacuum.
{"title":"Hydrogen etching of the SiC(0001) surface at moderate temperature","authors":"Toshiya Hamasaki, K. Yagyu, H. Mitani, T. Nishida, H. Tochihara, Takayuki Suzuki","doi":"10.1116/6.0001147","DOIUrl":"https://doi.org/10.1116/6.0001147","url":null,"abstract":"Hydrogen etching of a 4H-SiC(0001) surface at a moderate temperature of 1200 °C with molecular hydrogen gas was investigated to obtain enough flat and clean surface for large-scale high-quality epitaxial graphene synthesis. We found after a prolonged hydrogen etching that micro scratches, large depressions, and contaminations produced on the wafer in the manufacturing process disappeared and that a periodic array of atomic steps appeared, maintaining initial flat surface morphology. One hour of etching with a flow of 1.0 l/min was the optimum condition to obtain a flat and clean SiC surface in the present study. Using such surfaces, we were able to synthesize the so-called zero layer graphene by thermal annealing in ultrahigh vacuum.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"15 1","pages":"052801"},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85162048","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}
R. Bhattacharya, M. Turchetti, P. Keathley, K. Berggren, J. Browning
Lateral field emission devices have been characterized and degradation tested for >1000 h to study stability and reliability. Two types of planar device structures, diode and bowtie, were studied. These nanoscale devices have 10–20 nm tip to tip or tip to collector dimensions with the tips fabricated from Au/Ti. Typical currents of 2–6 nA at 6 V were measured. The devices were placed on lifetime tests in a vacuum of 1000 h. Seven total devices were tested with one failing at 300 h. and three of the devices showed <5% degradation in current until 1400 h when testing was stopped, and three other devices showed a sudden drop of ≈20% ranging from 700 to 900 h. Optical microscope images of one of the devices that failed catastrophically at 350 h show physical arc damage where the bond pad narrows to the emitter trace. Scanning electron microscope images of a bowtie part that completed 1400 h of operation showed no obvious erosion or damage to the tips.
{"title":"Long term field emission current stability characterization of planar field emitter devices","authors":"R. Bhattacharya, M. Turchetti, P. Keathley, K. Berggren, J. Browning","doi":"10.1116/6.0001182","DOIUrl":"https://doi.org/10.1116/6.0001182","url":null,"abstract":"Lateral field emission devices have been characterized and degradation tested for >1000 h to study stability and reliability. Two types of planar device structures, diode and bowtie, were studied. These nanoscale devices have 10–20 nm tip to tip or tip to collector dimensions with the tips fabricated from Au/Ti. Typical currents of 2–6 nA at 6 V were measured. The devices were placed on lifetime tests in a vacuum of 1000 h. Seven total devices were tested with one failing at 300 h. and three of the devices showed <5% degradation in current until 1400 h when testing was stopped, and three other devices showed a sudden drop of ≈20% ranging from 700 to 900 h. Optical microscope images of one of the devices that failed catastrophically at 350 h show physical arc damage where the bond pad narrows to the emitter trace. Scanning electron microscope images of a bowtie part that completed 1400 h of operation showed no obvious erosion or damage to the tips.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"1 1","pages":"053201"},"PeriodicalIF":0.0,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89222970","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}
R. Bhattacharya, N. Karaulac, G. Rughoobur, W. Chern, Akintunade Ibitayo Akinwande, J. Browning
The performance of silicon gated field emission arrays (GFEAs) was characterized before and after ultraviolet (UV) light exposure. Emission and gate leakage currents were measured on 1000 × 1000 tip arrays by sweeping the gate voltage to 40 V DC with a fixed DC collector voltage of 100 V DC. UV light exposure was used to desorb water molecules from the GFEA surfaces. It was found that, before UV exposure, the gate current was 6 mA at 40 V, whereas after 70 min of UV exposure, the gate current decreased to 0.46 mA, indicating a more than ten times reduction in leakage current between the gate and the emitter. Similarly, the observed collector current was 94 μA at 40 V before exposure, and after UV exposure, the collector current increased to 1.33 mA, indicating an improvement of more than 14 times. During the experiments with UV light, residual gas analyzer measurements showed that the partial pressure for water increased by greater than ten times after 60 min of exposure and then decreased by 1 order of magnitude after 100 min of exposure. The emission and leakage current changes remained even after turning off the UV lamps for several tens of minutes; however, upon the exposure to the atmosphere for a few days, those changes reversed. The enhancement could again be observed after additional UV exposure indicating that the adsorbates (mainly water along with others) on the surface affected the leakage between gate and emitter and field emission. Based on analysis of the IV characteristics before and after UV exposure, the work function of the emitter surfaces increases while the portion of the array tips that emits expands resulting in a decrease in the calculated array tip sharpness as duller tips now emit.
对硅门控场发射阵列(GFEAs)在紫外光照射前后的性能进行了表征。采用固定的直流集电极电压为100 V DC，将栅极电压扫至40 V DC，测量了1000 × 1000针尖阵列上的发射电流和栅漏电流。紫外照射用于从GFEA表面解吸水分子。研究发现，在UV照射前，栅极电流在40 V时为6 mA，而在UV照射70 min后，栅极电流降至0.46 mA，表明栅极与发射极之间的泄漏电流降低了10倍以上。同样，暴露前40 V时集电极电流为94 μA，紫外线照射后集电极电流增加到1.33 mA，提高了14倍以上。在紫外光下的实验中，残留气体分析仪的测量表明，水的分压在曝光60分钟后增加了10倍以上，而在曝光100分钟后又下降了1个数量级。即使在关闭紫外灯数十分钟后，发射电流和漏电流的变化仍然存在;然而，暴露在大气中几天后，这些变化发生了逆转。在额外的紫外线照射后，可以再次观察到增强，表明表面的吸附物(主要是水和其他物质)影响栅极和发射极之间的泄漏和场发射。根据紫外照射前后的IV特性分析，发射器表面的功函数增加，而阵列尖端发射的部分扩大，导致计算的阵列尖端锐度下降，因为较暗的尖端现在发射。
{"title":"Ultraviolet light stimulated water desorption effect on emission performance of gated field emitter array","authors":"R. Bhattacharya, N. Karaulac, G. Rughoobur, W. Chern, Akintunade Ibitayo Akinwande, J. Browning","doi":"10.1116/6.0001036","DOIUrl":"https://doi.org/10.1116/6.0001036","url":null,"abstract":"The performance of silicon gated field emission arrays (GFEAs) was characterized before and after ultraviolet (UV) light exposure. Emission and gate leakage currents were measured on 1000 × 1000 tip arrays by sweeping the gate voltage to 40 V DC with a fixed DC collector voltage of 100 V DC. UV light exposure was used to desorb water molecules from the GFEA surfaces. It was found that, before UV exposure, the gate current was 6 mA at 40 V, whereas after 70 min of UV exposure, the gate current decreased to 0.46 mA, indicating a more than ten times reduction in leakage current between the gate and the emitter. Similarly, the observed collector current was 94 μA at 40 V before exposure, and after UV exposure, the collector current increased to 1.33 mA, indicating an improvement of more than 14 times. During the experiments with UV light, residual gas analyzer measurements showed that the partial pressure for water increased by greater than ten times after 60 min of exposure and then decreased by 1 order of magnitude after 100 min of exposure. The emission and leakage current changes remained even after turning off the UV lamps for several tens of minutes; however, upon the exposure to the atmosphere for a few days, those changes reversed. The enhancement could again be observed after additional UV exposure indicating that the adsorbates (mainly water along with others) on the surface affected the leakage between gate and emitter and field emission. Based on analysis of the IV characteristics before and after UV exposure, the work function of the emitter surfaces increases while the portion of the array tips that emits expands resulting in a decrease in the calculated array tip sharpness as duller tips now emit.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"19 1","pages":"033201"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83558173","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 fabrication of resist patterns using UV nanoimprinting is required on consideration of the reduction of the use of hydrocarbons along recent amendments for environmental sustainability. In this study, we investigated the generation of resist pattern defects through UV nanoimprinting in a readily condensable trans-1,3,3,3-tetrafluoropropene (TFP) gas with a low global warming potential for elimination of nonfill defects arising from a bubble trap and subsequent sequential infiltration synthesis (SIS) to result in a vapor phase organic-inorganic hybridization for dry etching durability. A bisphenol A-based UV-curable imprint resin enabled the nanostructure fabrication of resist patterns without any nonfill defects in TFP; however, SIS consisting of subsequent mutual doses of trimethylaluminum and water caused a resist pattern collapse of 100-nm-height patterns with linewidths of <60 nm. A crosslinker with six acrylate moieties was selected based on its low TFP absorption. The crosslinker-containing imprint resin decreased the resist pattern collapse during SIS. Nanoindentation measurements suggest that the resist patterns made using the crosslinker-containing imprint resin were strengthened at 100 °C to carry out an SIS.
{"title":"Suppression of resist pattern collapse by crosslinker in ultraviolet nanoimprinting involving sequential infiltration synthesis with trimethylaluminum","authors":"C. Miyajima, Shunya Ito, M. Nakagawa","doi":"10.1116/6.0001014","DOIUrl":"https://doi.org/10.1116/6.0001014","url":null,"abstract":"The fabrication of resist patterns using UV nanoimprinting is required on consideration of the reduction of the use of hydrocarbons along recent amendments for environmental sustainability. In this study, we investigated the generation of resist pattern defects through UV nanoimprinting in a readily condensable trans-1,3,3,3-tetrafluoropropene (TFP) gas with a low global warming potential for elimination of nonfill defects arising from a bubble trap and subsequent sequential infiltration synthesis (SIS) to result in a vapor phase organic-inorganic hybridization for dry etching durability. A bisphenol A-based UV-curable imprint resin enabled the nanostructure fabrication of resist patterns without any nonfill defects in TFP; however, SIS consisting of subsequent mutual doses of trimethylaluminum and water caused a resist pattern collapse of 100-nm-height patterns with linewidths of <60 nm. A crosslinker with six acrylate moieties was selected based on its low TFP absorption. The crosslinker-containing imprint resin decreased the resist pattern collapse during SIS. Nanoindentation measurements suggest that the resist patterns made using the crosslinker-containing imprint resin were strengthened at 100 °C to carry out an SIS.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"20 6 1","pages":"032603"},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83084189","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 fabrication of alkoxysilane-based nickel (Ni)–palladium (Pd) bimetallic nanoparticle catalysts with several compositions (Pd—0.001M and Ni—0.001–0.1M) was attempted for the first time; these materials were investigated for use as low-cost catalysts in the hydrogen evolution reaction (HER). Functional alkoxysilane [2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane]-assisted conversion of Pd2+ to Pd0 was demonstrated. Palladium nanocrystallites with an average dimension 4.03 ± 1.29 nm were synthesized, which acted as seeds in the synthesis of Ni–Pd bimetallic nanoparticles. The effect of the nanoparticle catalysts on the HER in an alkaline environment was studied using linear sweep voltammetry and electrochemical impedance spectroscopy. A nanostructured thin film containing Ni3PdNPs produced a 100 mA cm−2 current density at an overpotential of −90 mV with a small Tafel slope of 25 mV dec−1 at a catalyst loading of 0.1 mg cm−2. The annealed Ni3PdNPs catalyst further enhanced the current density to ∼ 240 mA cm−2 at an overpotential of −56 mV.
{"title":"Organotrialkoxysilane-mediated synthesis of Ni–Pd nanocatalysts at lower concentrations of noble metal: Catalysts for faster hydrogen evolution kinetics","authors":"P. Pandey, Shubhangi Shukla, R. Narayan","doi":"10.1116/6.0000881","DOIUrl":"https://doi.org/10.1116/6.0000881","url":null,"abstract":"The fabrication of alkoxysilane-based nickel (Ni)–palladium (Pd) bimetallic nanoparticle catalysts with several compositions (Pd—0.001M and Ni—0.001–0.1M) was attempted for the first time; these materials were investigated for use as low-cost catalysts in the hydrogen evolution reaction (HER). Functional alkoxysilane [2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane]-assisted conversion of Pd2+ to Pd0 was demonstrated. Palladium nanocrystallites with an average dimension 4.03 ± 1.29 nm were synthesized, which acted as seeds in the synthesis of Ni–Pd bimetallic nanoparticles. The effect of the nanoparticle catalysts on the HER in an alkaline environment was studied using linear sweep voltammetry and electrochemical impedance spectroscopy. A nanostructured thin film containing Ni3PdNPs produced a 100 mA cm−2 current density at an overpotential of −90 mV with a small Tafel slope of 25 mV dec−1 at a catalyst loading of 0.1 mg cm−2. The annealed Ni3PdNPs catalyst further enhanced the current density to ∼ 240 mA cm−2 at an overpotential of −56 mV.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"33 1","pages":"032802"},"PeriodicalIF":0.0,"publicationDate":"2021-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81769848","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}
Dehua Li, Soo-Young Lee, Jin Choi, Seom-Beom Kim, Chan-uk Jeon
While electron-beam (e-beam) lithography is widely employed in the pattern transfer, the proximity effect makes features blurred, and the stochastic nature of the exposure and development processes causes the roughness in the feature boundaries. In an effort to reduce the proximity effect and line edge roughness (LER), it is often necessary to estimate the critical dimension (CD) and LER. In our previous study, the e-beam lithographic process was modeled using the information extracted from SEM images for the estimation of CD and LER. This modeling involves several parameters to be determined and tends to require a long computation time. In this study, the possibility of improving the accuracy of the CD and LER estimation using a neural network (NN) is investigated. In the NN-based estimation, the explicit modeling of the e-beam lithographic process can be avoided. This paper describes the method of estimating the CD and LER using a NN, including the issues of training, tuning, and sample reduction and presents results obtained through an extensive simulation.
{"title":"Estimation of critical dimension and line edge roughness using a neural network","authors":"Dehua Li, Soo-Young Lee, Jin Choi, Seom-Beom Kim, Chan-uk Jeon","doi":"10.1116/6.0000806","DOIUrl":"https://doi.org/10.1116/6.0000806","url":null,"abstract":"While electron-beam (e-beam) lithography is widely employed in the pattern transfer, the proximity effect makes features blurred, and the stochastic nature of the exposure and development processes causes the roughness in the feature boundaries. In an effort to reduce the proximity effect and line edge roughness (LER), it is often necessary to estimate the critical dimension (CD) and LER. In our previous study, the e-beam lithographic process was modeled using the information extracted from SEM images for the estimation of CD and LER. This modeling involves several parameters to be determined and tends to require a long computation time. In this study, the possibility of improving the accuracy of the CD and LER estimation using a neural network (NN) is investigated. In the NN-based estimation, the explicit modeling of the e-beam lithographic process can be avoided. This paper describes the method of estimating the CD and LER using a NN, including the issues of training, tuning, and sample reduction and presents results obtained through an extensive simulation.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"54 1","pages":"032602"},"PeriodicalIF":0.0,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86393889","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 study, we investigate the residual stress gradient of aluminum nitride thin film deposited by reactive pulse DC magnetron sputtering technique on a 200 mm diameter silicon wafer with a 1 μm layer of plasma enhanced chemical vapor deposition tetraethylorthosilicate. Stress measurements are obtained using in situ fabricated rotational beam microstructures. The rotating beam moves in response to relief of the residual stress on the connecting arms that experience lengthening or shortening due to compressive or tensile residual stresses, respectively. Various arm-beam connecting joints, separation gaps between the arms, and arm lengths are considered to determine the optimum microstructure for localized residual stress evaluation of the sputtered aluminum nitride. The displacement of the rotating beams with four different arm-beam connecting-joint designs is analytically modeled using COMSOL multiphysics finite element method simulation. The results of the analytical model were found to be in agreement with the results observed through experiments. The stress gradient measurements obtained using the microstructures are compared to the Stoney stress evaluated using a wafer bow technique. Although the predicted Stoney stress shows a 220 MPa tensile residual stress, the observed trend in localized stress values shows that the maximum stress is 280 MPa at the center of the wafer and reduces to about 100 MPa at the edge of the wafer.
{"title":"Thin films residual stress profile evaluation using test microstructures: Illustrated on an example of AlN film","authors":"Parsoua A. Sohi, I. Stateikina, M. Kahrizi","doi":"10.1116/6.0001032","DOIUrl":"https://doi.org/10.1116/6.0001032","url":null,"abstract":"In this study, we investigate the residual stress gradient of aluminum nitride thin film deposited by reactive pulse DC magnetron sputtering technique on a 200 mm diameter silicon wafer with a 1 μm layer of plasma enhanced chemical vapor deposition tetraethylorthosilicate. Stress measurements are obtained using in situ fabricated rotational beam microstructures. The rotating beam moves in response to relief of the residual stress on the connecting arms that experience lengthening or shortening due to compressive or tensile residual stresses, respectively. Various arm-beam connecting joints, separation gaps between the arms, and arm lengths are considered to determine the optimum microstructure for localized residual stress evaluation of the sputtered aluminum nitride. The displacement of the rotating beams with four different arm-beam connecting-joint designs is analytically modeled using COMSOL multiphysics finite element method simulation. The results of the analytical model were found to be in agreement with the results observed through experiments. The stress gradient measurements obtained using the microstructures are compared to the Stoney stress evaluated using a wafer bow technique. Although the predicted Stoney stress shows a 220 MPa tensile residual stress, the observed trend in localized stress values shows that the maximum stress is 280 MPa at the center of the wafer and reduces to about 100 MPa at the edge of the wafer.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"26 1","pages":"033001"},"PeriodicalIF":0.0,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73541100","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}
We report on the fabrication and characterization of fully vertical gallium nitride trench metal oxide semiconductor field effect transistors on native substrates with a metal-free gate first process and a chlorine-free trench etching method. Trenches were fabricated using sulfur hexafluoride and argon plasma etching in combination with alkaline wet etching posttreatment to create crystal oriented trenches along the a- and m-planes. Low pressure chemical vapor deposited silicon dioxide was used as gate dielectric with a poly-silicon gate contact. The metal-free gate structure was separated by a silicon dioxide passivation from any subsequent metal containing contact formation processing steps. The breakdown robustness of the gate structure was examined in the forward direction and no temperature dependence was observed up to 450 K. Fabricated trench MOSFETs showed only small hysteresis effects during transfer characterization but a positive threshold shift was observed. An inversion channel carrier field effect mobility of ≈ 10 cm 2/V s was extracted. The area specific on resistance was calculated to be 5.8 m Ω cm 2. Results for devices with differently oriented trenches were comparable and no significant performance difference was observed.
本文报道了采用无金属栅第一工艺和无氯沟槽刻蚀法在原生衬底上制备和表征了全垂直氮化镓沟槽金属氧化物半导体场效应晶体管。采用六氟化硫和氩等离子体刻蚀结合碱性湿法刻蚀后处理，沿a面和m面制备了晶体定向沟槽。采用低压化学气相沉积二氧化硅作为栅极介质，并采用多晶硅栅极触点。无金属栅极结构通过二氧化硅钝化与任何后续含金属接触形成加工步骤分离。栅极结构的击穿稳健性在正向方向上进行了测试，并且在450k以下没有观察到温度依赖性。制备的沟槽mosfet在转移表征过程中仅表现出较小的滞后效应，但观察到正的阈值移位。反演通道载流子场效应迁移率为≈10 cm 2/V s。计算出电阻比面积为5.8 m Ω cm 2。不同定向沟槽装置的结果具有可比性，没有观察到显著的性能差异。
{"title":"Fully vertical gallium nitride trench MOSFETs fabricated with metal-free gate first process","authors":"Kevin Dannecker, J. Baringhaus","doi":"10.1116/6.0000980","DOIUrl":"https://doi.org/10.1116/6.0000980","url":null,"abstract":"We report on the fabrication and characterization of fully vertical gallium nitride trench metal oxide semiconductor field effect transistors on native substrates with a metal-free gate first process and a chlorine-free trench etching method. Trenches were fabricated using sulfur hexafluoride and argon plasma etching in combination with alkaline wet etching posttreatment to create crystal oriented trenches along the a- and m-planes. Low pressure chemical vapor deposited silicon dioxide was used as gate dielectric with a poly-silicon gate contact. The metal-free gate structure was separated by a silicon dioxide passivation from any subsequent metal containing contact formation processing steps. The breakdown robustness of the gate structure was examined in the forward direction and no temperature dependence was observed up to 450 K. Fabricated trench MOSFETs showed only small hysteresis effects during transfer characterization but a positive threshold shift was observed. An inversion channel carrier field effect mobility of ≈ 10 cm 2/V s was extracted. The area specific on resistance was calculated to be 5.8 m Ω cm 2. Results for devices with differently oriented trenches were comparable and no significant performance difference was observed.","PeriodicalId":17652,"journal":{"name":"Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena","volume":"16 1","pages":"032204"},"PeriodicalIF":0.0,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91142055","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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