跨临界CO2汽车空调系统的有效能分析

本文通过数值计算,对跨临界CO2汽车空调系统进行了有效能分析,计算讨论了在不同的内部换热器高压侧流体出口温度,以及不同的压缩机吸气过热度的情况下,系统的制冷系数(COP)、单位有效能损失与有效能效率随着高压侧压力变化的情况;同时还分析了在不同的蒸发压力下,系统有效能效率随着高压侧压力的变化情况.……     

C2F6 /O2 /Ar Plasma Chemistry of 60 MHz/2 MHz Dual-Frequency Discharge and Its Effect on Etching of SiCOH Low-k Film

This work investigated C2F6/O2 /Ar plasma chemistry and its effect on the etching characteristics of SiCOH low-k dielectrics in 60 MHz/2 MHz dual-frequency capacitively coupled discharge. For the C2F6/Ar plasma, the increase in the low-frequency (LF) power led to an increased ion impact, prompting the dissociation of C2F6 with higher reaction energy. As a result, fluorocarbon radicals with a high F/C ratio decreased. The increase in the discharge pressure led to a decrease in the electron temperature, resulting in the decrease of C2F6 dissociation. For the C2F6/O2 /Ar plasma, the increase in the LF power prompted the reaction between O2 and C2F6 , resulting in the elimination of CF3 and CF2 radicals, and the production of an F-rich plasma environment. The F-rich plasma improved the etching characteristics of SiCOH low-k films, leading to a high etching rate and a smooth etched surface.     

跨临界CO_2汽车空调系统的有效能分析

文通过数值计算,对跨临界CO2汽车空调系统进行了有效能分析,计算讨论了在不同的内部换热器高压侧流体出口温度,以及不同的压缩机吸气过热度的情况下,系统的制冷系数(COP)、单位有效能损失与有效能效率随着高压侧压力变化的情况;同时还分析了在不同的蒸发压力下,系统有效能效率随着高压侧压力的变化情况。     

Effect of Low-frequency Power on F, CF2 Relative Density and F/CF2 Ratio in Fluorocarbon Dual-Frequency Plasmas

Effect of low-frequency power on F, CF₂ relative density and F/CF₂ ratio, in C₂F₆, C₄F₈ and CHF₃ dual-frequency capacitively couple discharge driven by the power of 13.56 MHz/2 MHz, was investigated by using optical emission spectroscopy. High F, CF₂ relative density and high F/CF₂ ratio were obtained in a CHF₃ plasma. But for C2F6 and C4F8 plasmas, the F, CF₂ relative density and F/CF₂ ratio all decreased significantly due to the difference in both reactive paths and reactive energy. The increase of LF power caused simultaneous increase of F and CF₂ radical relative densities in C₄F₈ and CHF₃ plasmas, but led to increase of F with the decrease in CF₂ relative densities in C₂F₆ plasma due to the increase of lower energy electrons and the decrease of higher energy electrons in EEDF.     

Effect of Low-Frequency Power on Etching Characteristics of 6H-SiC in C_4F_8/Ar Dual-Frequency Capacitively Coupled Plasma

Dry etching of 6H silicon carbide(6H-SiC)wafers in a C_4Fs/Ar dual-frequency capacitively coupled plasma(DF-CCP)was investigated.Atomic force microscopy(AFM)and X-ray photoelectron spectroscopy(XPS)were used to measure the SiC surface structure and compositions,respectively.Optical emission spectroscopy(OES)was used to measure the relative concentration of F radicals in the plasma.It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency(LF)source.At lower LF power,a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers.At higher LF power the etching rate can be efficiently increased,but the surface roughness increases too.Compared with other plasma dry etching methods,the DF-CCP can effectively inhibit C_xF_y films'deposition,and reduce surface residues.     

跨临界CO2汽车空调系统的有效能分析

本文通过数值计算，对跨临界CO2汽车空调系统进行了有效能分析，计算讨论了在不同的内部换热器高压侧流体出口温度，以及不同的压缩机吸气过热度的情况下，系统的制冷系数(COP)、单位有效能损失与有效能效率随着高压侧压力变化的情况；同时还分析了在不同的蒸发压力下，系统有效能效率随着高压侧压力的变化情况。