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81.
Perfluorocarbon gas is widely used in the semiconductor industry. However, perfluorocarbon has a
negative effect on the global environment owing to its high global warming potential (GWP) value.
An alternative solution is essential. Therefore, we evaluated the possibility of replacing conventional
perfluorocarbon etching gases such as CHF3 with C6F12O, which has a low GWP and is in a liquid
state at room temperature. In this study, silicon oxynitride (SiON) films were plasma-etched using
inductively coupled CF4 +C6F12O+O2 mixed plasmas. Subsequently, the etching characteristics
of the film, such as etching rate, etching profile, selectivity over Si, and photoresist, were investigated.
A double Langmuir probe was used and optical emission spectroscopy was performed for plasma
diagnostics. In addition, a contact angle goniometer and x-ray photoelectron spectroscope were used
to confirm the change in the surface properties of the etched SiON film surface. Consequently, the
etching characteristics of the C6F12O mixed plasma exhibited a lower etching rate, higher SiON/Si
selectivity, lower plasma damage, and more vertical etched profiles than the conventional CHF3 mixed plasma. In addition, the C6F12O gas can be recovered in the liquid state, thereby decreasing
global warming. These results confirmed that the C6F12O precursor can sufficiently replace the
conventional etching gas. 相似文献
82.
采用物理气相传输(PVT)法进行高纯半绝缘SiC晶体生长,利用高温真空解吸附以及在系统中通入HCl和H2的方法,有效降低了系统中N、B和Al等杂质的背景浓度。使用二次离子质谱(SIMS)对晶体中杂质浓度测试,N、B和Al浓度分别小于1×1016、1×1015和2×1014 cm-3。对加工得到的晶片进行测试,全片的电阻率均在1×1010Ω·cm以上,微管密度小于0.02 cm-2,(004)衍射面的X射线摇摆曲线半高宽为34″。结果表明,该方法可以有效降低SiC晶体中N、B和Al等杂质浓度,提升SiC晶片的电阻率。使用该方法成功制备了4英寸(1英寸=2.54 cm)高纯半绝缘4H-SiC晶体。 相似文献
83.
Dulal Das Sanchita Baitalik Nijhuma Kayal 《International Journal of Applied Ceramic Technology》2020,17(2):476-483
Multiple oxide-bonded porous SiC ceramics were fabricated by infiltrating a porous powder compact of SiC and alumina with cordierite sol followed by sintering at 1300-1400°C in air for 3 hours. The microstructures, phase components, mechanical properties, and air permeation behavior of the developed porous ceramics were examined and compared with materials obtained by the traditional powder processing route. The porosity, average pore diameter, and flexural strength of the ceramics varied from 33 to 37 vol%, ~12-14 μm and ~23-39.6 MPa, respectively, with variation in sintering temperature. The X-ray diffraction results reveal that both the amount of cordierite and mullite as the binder increased with increase in sintering temperature. In addition, it was found that the addition of alumina in powder form effectively enhanced the strength due to formation of mullite in the bond phase in contrast to the samples prepared without alumina additive. To determine the suitability of the material in particulate filtration application, particle collection efficiency of the filter material was evaluated theoretically using single collector efficiency model. 相似文献
84.
针对某乘用车发动机转速在1 573 r/min,压缩机开启时车内噪声异常的问题,对样车进行试验分析与诊断,对压缩机-支架系统进行仿真分析,提出改进方案并验证改进效果。利用LMS声振信号采集系统采集振动噪声数据,采用频谱分析、阶次追踪等方法,并结合压缩机-支架系统模态仿真结果,确定车内异常噪声是压缩机轴频21阶与压缩机-支架系统3阶模态频率接近发生共振造成的。通过优化支架结构来提高压缩机-支架系统3阶模态频率以此来避免共振,并换装橡胶驱动盘缓和压缩机输入扭矩波动。将改进结构进行整车试验,结果表明:匀速工况空调开启时问题转速下,车内噪声降低了2.5 dB(A);匀加速工况空调开启时发动机转速1 500~1 650 r/min区间,车内噪声无峰值,其余转速空调开启时改进前/后车内噪声基本不变,噪声波动趋势平缓。 相似文献
85.
Leonardo I. Farfán-Cabrera Cesar D. Reséndiz-Calderón Cesar Sedano de la Rosa 《摩擦学汇刊》2018,61(4):640-647
This article aims to investigate the degradation of physical and tribological properties (friction coefficients and wear resistance) of a dynamic sealing material (silicone rubber [VMQ]) exposed to Jatropha oil (JO), engine mineral oil (EMO), and a blend (B20; 80% EMO–20% JO), separately. JO has demonstrated better lubricating properties than EMO in various mechanical applications; however, the degradation of elastomers by using this oil has not been studied yet, nor have its effect on their tribological properties. The physical degradation was evaluated by conducting static immersion tests (670 h at 25 °C) based on ASTM-D471 and ASTM-D7216 methods. Hence, the changes in mass, volume, tensile and tear strengths, and hardness of VMQ were measured. In addition, creep compliance tests were conducted to determine the changes in viscoelastic properties and the changes in morphology and topography were measured by scanning electron microscopy (SEM) and optical profilometry, respectively. In addition, the compositional changes were determined by Fourier transform infrared (FTIR) analyses to complement the degradation examination. Changes in the friction coefficients were determined by ball-on-disk tests and changes in wear resistance were obtained by accelerated wear tests (microabrasion tests). Finally, VMQ exhibited no significant physical and compositional degradation due to immersion in the three lubricants. However, considerable changes in the friction coefficients and wear resistance were observed; the change in the friction coefficients was minimal using JO. In addition, the coefficients using JO were 50% lower than those for EMO and the changes in wear resistance were lowest after immersion in JO. 相似文献
86.
Nicolás Emanuel Tenaglia Roberto Enrique Boeri Juan Miguel Massone Alejandro Daniel Basso 《Materials Science & Technology》2018,34(16):1990-2000
The austemperability of seven high silicon cast steels with different alloy contents was characteri sed. The maximum round bar diameter that can be fully austempered changed from about 10?mm for an unalloyed steel to more than 70?mm for a low-alloy steel. The austemperability was calculated by applying a procedure based on a standard Jominy test and the characterisation of the microstructure along the Jominy sample. The method, which was validated experimentally, creates a relatively simple procedure to measure austemperability. Processing factors such as the ability of the salt bath to extract heat and the austempering temperature are accounted for the method. The metallographic study revealed the influence of microsegregation on hardenability, which is particularly important for cast steels. 相似文献
87.
Mylena M.M. Carrijo Hannes Lorenz Carlos R. Rambo Peter Greil Nahum Travitzky 《Ceramics International》2018,44(7):8116-8124
This paper describes the development and fabrication of pastes suitable for screen printing process using Ti3SiC2 as the ceramic filler and ethyl cellulose as the binder. With the aim of obtaining high quality screen printed films, the influence of different amounts of Ti3SiC2 filler (20–40?vol%) and binder (0–5?vol%) on the rheological properties of the pastes was investigated. Samples with higher viscosity, such as pastes containing 30?vol% and 40?vol% Ti3SiC2 filler, regardless of the amount of ethyl cellulose, showed a higher printing quality compared to the samples with other compositions. The different paste compositions were screen printed onto paper-derived Al2O3 substrates containing 28.6 ± 4.8% open porosity and sintered for 1?h under an argon atmosphere at 1600?°C. X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM) analysis showed that the sintered films contained TiC as a primary phase and Ti3SiC2 as a secondary phase. The partial decomposition of Ti3SiC2 after sintering can be attributed to residual carbon from the organic additives, which decreases the thermal stability of this material. 相似文献
88.
Binbin Chen Nicolas Gauquelin Daen Jannis Daniel M. Cunha Ufuk Halisdemir Cinthia Piamonteze Jin Hong Lee Jamal Belhadi Felix Eltes Stefan Abel Zoran Jovanović Matjaž Spreitzer Jean Fompeyrine Johan Verbeeck Manuel Bibes Mark Huijben Guus Rijnders Gertjan Koster 《Advanced materials (Deerfield Beach, Fla.)》2020,32(50):2004995
89.
90.
金属橡胶元件的应力应变关系为非线性滞回曲线,现有的金属橡胶动力学模型大多采用多参数、分段函数进行描述,增加了系统的复杂性。通过分析金属橡胶的弹性恢复力和阻尼力的组成,利用分数阶微分能够描述各种材料及过程记忆性的特点,提出一种含有分数阶微分的金属橡胶黏弹性本构模型,在此模型基础上建立了金属橡胶非线性动力学系统模型;通过正弦位移加载实验获取了典型金属橡胶隔振系统在多种激励幅值、频率作用下的恢复力;采用遗传算法对实验数据进行曲线拟合,识别出模型中所有参数;通过分析推导出系统模型中各参数与振幅及频率的函数关系。结果表明,所提出的含分数阶微分项的金属橡胶非线性动力学系统模型,具有连续的数学表达式,能够较准确地反映金属橡胶非线性系统的完整动力学性能,而且与现有金属橡胶动力学系统模型相比,参数较少,结构简单,为金属橡胶动力学系统的研究提供了新的思路。 相似文献