提出了基于光纤布拉格光栅（FBG）包层模式的折射率传感方案。实验中，利用不同浓度的丙三醇水溶液作为外界折射率传感溶液，采用氢氟酸溶液化学腐蚀的方法来减小光纤包层的直径以增大包层模式对外界折射率的敏感度，研究了腐蚀后光纤...提出了基于光纤布拉格光栅（FBG）包层模式的折射率传感方案。实验中，利用不同浓度的丙三醇水溶液作为外界折射率传感溶液，采用氢氟酸溶液化学腐蚀的方法来减小光纤包层的直径以增大包层模式对外界折射率的敏感度，研究了腐蚀后光纤布拉格光栅包层模式的耦合波长对外部折射率的变化关系。实验结果表明在1．3300-1．4584的折射率范围内，包层模式耦合波长随外界折射率增大而增大，在接近光纤包层折射率处具有很高的折射率灵敏度，最大达到了172nm／riu（refractive index unit）。而且，包层模谐振的光谱半峰全宽（约0．07nm）仅为布拉格纤芯模谐振光谱半峰全宽的1／4，能够获得更好的传感精度。展开更多
Gas spark switch is one of the key parts in pulsed power technology.Electrode erosion has great influence on the switch performance and lifetime.In this paper,a field distortion gas switch is selected for the experime...Gas spark switch is one of the key parts in pulsed power technology.Electrode erosion has great influence on the switch performance and lifetime.In this paper,a field distortion gas switch is selected for the experiment and a great deal of discharging experiments have been conducted in different test conditions.The forming process of etch pit as well as its influencing factors is discussed briefly and surface roughness coefficient(SRC) of the electrode is put forward to evaluate the state of electrode erosion.Experimental results show that current peak plays an important role in electrode erosion when waveforms of discharge current are the same,and electric charge and oscillation frequency of discharge current also have great effect on the electrode erosion when waveforms of discharge current are different.With the increase of discharge times,SRC decreases slowly at first and then decreases quickly after three thousand of discharge times.展开更多
A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etc...A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.展开更多
Inductively coupled plasma （ICP） etching of single crystal 6H-silicon carbide （SIC） is investigated using oxygen （O2）-added sulfur hexafluoride （SF6） plasmas. The relations between the microtrenching effect an...Inductively coupled plasma （ICP） etching of single crystal 6H-silicon carbide （SIC） is investigated using oxygen （O2）-added sulfur hexafluoride （SF6） plasmas. The relations between the microtrenching effect and ICP coil power, the composition of the etch gases and different bias voltages are discussed. Experimental results show that the microtrench is caused by the formation of a SiFxOy layer, which has a greater tendency to charge than SiC, after the addition of O2. The microtrenching effect tends to increase as the ICP coil power and bias voltage increase. In addition, the angular distribution of the incident ions and radicals also affects the shape of the microtrench.展开更多
设计出一款可应用于RFID(Radio Frequency Identification)系统的5.8 GHz传统矩形微带天线,天线辐射贴片尺寸为15.74 mm×11.12 mm,天线的回波损耗(S11)的实测结果为-23.276 d B。此后,在矩形微带天线基础上进行设计改进,通过分别蚀...设计出一款可应用于RFID(Radio Frequency Identification)系统的5.8 GHz传统矩形微带天线,天线辐射贴片尺寸为15.74 mm×11.12 mm,天线的回波损耗(S11)的实测结果为-23.276 d B。此后,在矩形微带天线基础上进行设计改进,通过分别蚀刻15个超材料结构I型谐振环和6个超材料结构开口谐振环SRR(Split Resonant Ring),构造出两款新型小型化天线。与传统矩形天线相比,在保持方向性、最大增益等参数性能基本不变的条件下,基于超材料结构的天线辐射贴片尺寸分别为12.44mm×9.12 mm和11.74 mm×9.1 mm,相比传统矩形天线分别缩小了35.2%和41.82%,辐射贴片小型化效果明显,其回波损耗实测结果分别为-21.83 d B和-15.40 d B。展开更多
Mechanical properties and corrosion resistance of Si3N4 films are studied by using different experiment parameters, such as plasma enhanced chemical vapor deposition(PECVD) RF power, ratio of reaction gas, reaction pr...Mechanical properties and corrosion resistance of Si3N4 films are studied by using different experiment parameters, such as plasma enhanced chemical vapor deposition(PECVD) RF power, ratio of reaction gas, reaction pressure and working temperature. The etching process of Si3N4 is studied by inductively coupled plasma (ICP) with a gas mixture of SF6 and O2. The influence of the technique parameters, such as ICP power, DC bias, gas composition, total flow rate, on the etching selectivity of Si3N4/EPG533 which is used as a mask layer and the etching rate of Si3N4 is studied, in order to get a better etching selectivity of Si3N4/EPG533 with a faster etching rate of Si3N4. The optimized process parameters of etching Si3N4 by ICP are obtained after a series of experiments and analysis. Under the conditions of total ICP power of 250 W, DC bias of 50W, total flow rate of 40 sccm and O2 composition of 30%, the etching selectivity of 2.05 can be reached when Si3N4 etching rate is 336 nm/min.展开更多
A simple preparation of ultrathin nanoporous gold film was described. Copper and gold were used to fabricate Cu-Au alloy films through vacuum deposition. The formation of nanoporous gold films from the alloy films inv...A simple preparation of ultrathin nanoporous gold film was described. Copper and gold were used to fabricate Cu-Au alloy films through vacuum deposition. The formation of nanoporous gold films from the alloy films involved thermal process and chemical etch by hydrochloric acid or by nitric acid. The free-standing nanoporous gold films have been analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectrometer （XPS） and surface-enhanced Raman scattering （SELLS）. R was noted that the nanoporous gold film etched by hydrochloric acid is uniform with a cover of fog-like moieties.展开更多
文摘提出了基于光纤布拉格光栅（FBG）包层模式的折射率传感方案。实验中，利用不同浓度的丙三醇水溶液作为外界折射率传感溶液，采用氢氟酸溶液化学腐蚀的方法来减小光纤包层的直径以增大包层模式对外界折射率的敏感度，研究了腐蚀后光纤布拉格光栅包层模式的耦合波长对外部折射率的变化关系。实验结果表明在1．3300-1．4584的折射率范围内，包层模式耦合波长随外界折射率增大而增大，在接近光纤包层折射率处具有很高的折射率灵敏度，最大达到了172nm／riu（refractive index unit）。而且，包层模谐振的光谱半峰全宽（约0．07nm）仅为布拉格纤芯模谐振光谱半峰全宽的1／4，能够获得更好的传感精度。
基金Project Supported by National Natural Science Foundation of China(No.50637010)
文摘Gas spark switch is one of the key parts in pulsed power technology.Electrode erosion has great influence on the switch performance and lifetime.In this paper,a field distortion gas switch is selected for the experiment and a great deal of discharging experiments have been conducted in different test conditions.The forming process of etch pit as well as its influencing factors is discussed briefly and surface roughness coefficient(SRC) of the electrode is put forward to evaluate the state of electrode erosion.Experimental results show that current peak plays an important role in electrode erosion when waveforms of discharge current are the same,and electric charge and oscillation frequency of discharge current also have great effect on the electrode erosion when waveforms of discharge current are different.With the increase of discharge times,SRC decreases slowly at first and then decreases quickly after three thousand of discharge times.
文摘A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.
基金supported by the Chinese National Advance Research Program of Science and Technology (Nos. 51308030201, 51323040118)
文摘Inductively coupled plasma （ICP） etching of single crystal 6H-silicon carbide （SIC） is investigated using oxygen （O2）-added sulfur hexafluoride （SF6） plasmas. The relations between the microtrenching effect and ICP coil power, the composition of the etch gases and different bias voltages are discussed. Experimental results show that the microtrench is caused by the formation of a SiFxOy layer, which has a greater tendency to charge than SiC, after the addition of O2. The microtrenching effect tends to increase as the ICP coil power and bias voltage increase. In addition, the angular distribution of the incident ions and radicals also affects the shape of the microtrench.
文摘设计出一款可应用于RFID(Radio Frequency Identification)系统的5.8 GHz传统矩形微带天线,天线辐射贴片尺寸为15.74 mm×11.12 mm,天线的回波损耗(S11)的实测结果为-23.276 d B。此后,在矩形微带天线基础上进行设计改进,通过分别蚀刻15个超材料结构I型谐振环和6个超材料结构开口谐振环SRR(Split Resonant Ring),构造出两款新型小型化天线。与传统矩形天线相比,在保持方向性、最大增益等参数性能基本不变的条件下,基于超材料结构的天线辐射贴片尺寸分别为12.44mm×9.12 mm和11.74 mm×9.1 mm,相比传统矩形天线分别缩小了35.2%和41.82%,辐射贴片小型化效果明显,其回波损耗实测结果分别为-21.83 d B和-15.40 d B。
文摘Mechanical properties and corrosion resistance of Si3N4 films are studied by using different experiment parameters, such as plasma enhanced chemical vapor deposition(PECVD) RF power, ratio of reaction gas, reaction pressure and working temperature. The etching process of Si3N4 is studied by inductively coupled plasma (ICP) with a gas mixture of SF6 and O2. The influence of the technique parameters, such as ICP power, DC bias, gas composition, total flow rate, on the etching selectivity of Si3N4/EPG533 which is used as a mask layer and the etching rate of Si3N4 is studied, in order to get a better etching selectivity of Si3N4/EPG533 with a faster etching rate of Si3N4. The optimized process parameters of etching Si3N4 by ICP are obtained after a series of experiments and analysis. Under the conditions of total ICP power of 250 W, DC bias of 50W, total flow rate of 40 sccm and O2 composition of 30%, the etching selectivity of 2.05 can be reached when Si3N4 etching rate is 336 nm/min.
基金This work was supported by the National Natural Science Foundation of China(No.60171008)Shanghai Science and Technology Committee(No.0214nm005,No.0452nm087).
文摘A simple preparation of ultrathin nanoporous gold film was described. Copper and gold were used to fabricate Cu-Au alloy films through vacuum deposition. The formation of nanoporous gold films from the alloy films involved thermal process and chemical etch by hydrochloric acid or by nitric acid. The free-standing nanoporous gold films have been analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectrometer （XPS） and surface-enhanced Raman scattering （SELLS）. R was noted that the nanoporous gold film etched by hydrochloric acid is uniform with a cover of fog-like moieties.
