The high deposition of microcrystalline silicon thin film by very high frequency plasma enhanced chemical vapour deposition and the fabrication of solar cells

This paper reports that the intrinsic microcrystalline silicon （μc-Si：H） films are prepared with plasma enhanced chemical vapour deposition from silane/hydrogen mixtures at 200℃ with the aim to increase the deposition rate. An increase of the deposition rate to 0.88 nm/s is obtained by using a plasma excitation frequency of 75 MHz. This increase is obtained by the combination of a higher deposition pressure, an increased silane concentration, and higher discharge powers. In addition, the transient behaviour, which can decrease the film crystallinity, could be prevented by filling the background gas with H2 prior to plasma ignition, and selecting proper discharging time after silane flow injection. Material prepared under these conditions at a deposition rate of 0.78nm/s maintains higher crystallinity and fine electronic properties. By H-plasma treatment before i-layer deposition, single junction μc-Si：H solar cells with 5.5% efficiency are fabricated.

Influence of oxygen on the growth of cubic boron nitride thin films by plasma-enhanced chemical vapour deposition

Cubic boron nitride thin films were deposited on silicon substrates by low-pressure inductively coupled plasmaenhanced chemical vapour deposition. It was found that the introduction of 02 into the deposition system suppresses both nucleation and growth of cubic boron nitride. At a B2H6 concentration of 2.5% during film deposition, the critical O2 concentration allowed for the nucleation of cubic boron nitride was found to be less than 1.4%, while that for the growth of cubic boron nitride was higher than 2.1%. Moreover, the infrared absorption peak observed at around 1230- 1280 cm^-1, frequently detected for cubic boron nitride films prepared using non-ultrahigh vacuum systems, appears to be due to the absorption of boron oxide, a contaminant formed as a result of the oxygen impurity. Therefore, the existence of trace oxygen contamination in boron nitride films can be evaluated qualitatively by this infrared absorption peak.

Electron field emission characteristics of nano-catkin carbon films deposited by electron cyclotron resonance microwave plasma chemical vapour deposition

This paper reported that the nano-catkin carbon films were prepared on Si substrates by means of electron cyclotron resonance microwave plasma chemical vapour deposition in a hydrogen and methane mixture. The surface morphology and the structure of the fabricated films were characterized by using scanning electron microscopes and Raman spectroscopy, respectively. The stable field emission properties with a low threshold field of 5V/μm corresponding to a current density of about 1μA/cm^2 and a current density of 3.2mA/cm^2 at an electric field of 10V/μm were obtained from the carbon film deposited at CH4 concentration of 8%. The mechanism that the threshold field decreased with the increase of the CH4 concentration and the high emission current appeared at the high CH4 concentration was explained by using the Fowler-Nordheim theory.

Field emission characteristics of nano-sheet carbon films deposited by quartz-tube microwave plasma chemical vapour deposition

Nano-sheet carbon films are prepared on Si wafers by means of quartz-tube microwave plasma chemical vapour deposition （MPCVD） in a gas mixture of hydrogen and methane. The structure of the fabricated films is investigated by using field emission scanning electron microscope （FESEM） and Raman spectroscopy. These nano^carbon films are possessed of good field emission （FE） characteristics with a low threshold field of 2.6 V/μm and a high current density of 12.6 mA/cm^2 at an electric field of 9 V/μm. As the FE currents tend to be saturated in a high E region, no simple Fowler-Nordheim （F-N） model is applicable. A modified F N model considering statistic effects of FE tip structures and a space-charge-limited-current （SCLC） effect is applied successfully to explaining the FE data observed at low and high electric fields, respectively.

Influence of ignition condition on the growth of silicon thin films using plasma enhanced chemical vapour deposition

The influences of the plasma ignition condition in plasma enhanced chemical vapour deposition （PECVD） on the interfaces and the microstructures of hydrogenated microcrystalline Si （μc-Si：H） thin films are investigated. The plasma ignition condition is modified by varying the ratio of Sill4 to H2 （RH）. For plasma ignited with a constant gas ratio, the time-resolved optical emission spectroscopy presents a low value of the emission intensity ratio of Ha to Sill＊ （Iuα//SiH＊） at the initial stage, which leads to a thick amorphous incubation layer. For the ignition condition with a profiling RH, the higher IHα/ISiH＊ values are realized. By optimizing the RN modulation, a uniform crystallinity along the growth direction and a denser αc-Si：H film can be obtained. However, an excessively high IRα/ISIH＊ may damage the interface properties, which is indicated by capacitance-voltage （C-V） measurements. Well controlling the ignition condition is critically important for the applications of Si thin films.

Diagnosis of gas phase near the substrate surface in diamond film deposition by high-power DC arc plasma jet CVD

Optical emission spectroscopy （OES） was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition （CVD）. C2 radical was determined as the main carbon radical in this plasma atmosphere. The deposition parameters, such as substrate temperature, anode-substrate distance, methane concentration, and gas flow rate, were inspected to find out the influence on the gas phase. A strong dependence of the concentrations and distribution of radicals on substrate temperature was confirmed by the design of experiments （DOE）. An explanation for this dependence could be that radicals near the substrate surface may have additional ionization or dissociation and also have recombination, or are consumed on the substrate surface where chemical reactions occur.

Impact of strain relaxation on the growth rate of heteroepitaxial germanium tin binary alloy

The growth of high-quality germanium tin(Ge_(1–y)Sn_(y))binary alloys on a Si substrate using chemical vapor deposition(CVD)techniques holds immense potential for advancing electronics and optoelectronics applications,including the development of efficient and low-cost mid-infrared detectors and light sources.However,achieving precise control over the Sn concentration and strain relaxation of the Ge_(1–y)Sn_(y)epilayer,which directly influence its optical and electrical properties,remain a significant challenge.In this research,the effect of strain relaxation on the growth rate of Ge_(1–y)Sn_(y)epilayers,with Sn concentration>11at.%,is investigated.It is successfully demonstrated that the growth rate slows down by~55%due to strain relaxation after passing its critical thickness,which suggests a reduction in the incorporation of Ge into Ge_(1–y)Sn_(y)growing layers.Despite the increase in Sn concentration as a result of the decrease in the growth rate,it has been found that the Sn incorporation rate into Ge_(1–y)Sn_(y)growing layers has also decreased due to strain relaxation.Such valuable insights could offer a foundation for the development of innovative growth techniques aimed at achieving high-quality Ge_(1–y)Sn_(y)epilayers with tuned Sn concentration and strain relaxation.

Structural Evolution of SiC Films During Plasma-Assisted Chemical Vapour Deposition

Evolution of chemical bonding configurations for the films deposited from hexam- ethyldisiloxane （HMDSO） diluted with H2 during plasma assisted chemical vapour deposition is investigated. In the experiment a small amount of CH4 was added to adjust the plasma environment and modify the structure of the deposited films. The measurements of Raman spectroscopy and X-ray diffraction （XRD） revealed the production of 6H-SiC embedded in the amorphous matrix without the input of CH4. As CH4 was introduced into the deposition reaction, the transition of 6H-SiC to cubic SiC in the films took place, and also the film surfaces changed from a structure of ellipsoids to cauliflower-like shapes. With a further increase of CH4 in the flow ratio, the obtained films varied from Si-C bonding dominant to a sp^2/sp^3 carbon-rich composition.

Influence of the Plasma State on the Formation of Nano Crystalline SiC Films

The influence of the plasma state on the microstructure transformation from amorphous to nano-(crystalline) state is emphasized during the formation of the silicon carbide (SiC) films deposited by the plasma enhanced chemical vapor technique. The effect of two key parameters, the working pressure and hydrogen concentration in the gas flow, that perform the dependence by modulating the two essential factors of the plasma state-ions energy and gas composition, is in-depth investigated. The experimental results showed that nanocrystalline SiC films fit for field emitters could be achieved under an appropriate ion energy flow density and gas components in the (plasma.)

Preparation of the In_2O_23·Sn Films by MO-CVD Technique

Introduction In;O;·Sn films have high transparency（>95％） within the visible spectral region, low resistivity(10;—10;ohm·cm) at room temperature and superior thermal stability. These films have been applied to solar cells, electronics and photoelectronics fields. In recent years, organometallic-CVD method has emerged as a successful alternate to the physical methods and general CVD for the growth of these films. The MO-CVD tech-

DC PJ－CVD等离子体炬通道中的电弧行为

运用电磁学和热流体学的方法研究了直流大阳极喷嘴长电弧通道等离子体炬中电弧的行为，并通过实验证明了温度梯度与电场梯度作用于流体时所产生的特殊现象；结果表明：电弧弧柱的高温效应剧烈排斥冷气流的混入，使ＣＶＤ过程受到抑制。新产生的胶体粒子在热泳现象作用下逐渐沉积于通道内壁上。改变不同气体的进气位置以及减小温度与电场梯度并增设径向旋转磁场。

PCVD TiN膜的界面制备及性能

用TiCl4作为反应气体制备PCVDTiN镀层，对降低界面的氧含量，改善PCVDTiN镀层的界面性能进行了研究。在镀层制备过程中增加了界面制备过程，即采用氩离子轰击以及氢的反应使界面的氯含量降低，膜基界面得到改善。结果表明，与常规PCVD制备的TiN镀层相比，膜层的结合强度有大幅度的提高，耐磨性和耐蚀性均有改善，特别是其耐蚀性达到甚至超过奥氏体不锈钢的水平。

DC-PCVD法快速制备Si_3N_4薄膜

采用ＤＣＰＣＶＤ方法，控制工艺参数，在ＧＣｒ１５钢试样上获得４０μｍ厚的、以Ｓｉ３Ｎ４为主要成分的非晶态绝缘薄膜，沉积速率约为３７／ｓ。讨论了沉积速率高的原因。

离子氮化-PECVD TiN膜复合处理提高切边模具寿命研究

对用于制作冷作模具的两种高速钢W 18Cr4V和W 6Mo5Cr4V2Al进行离子渗氮 -PECVDTiN复合处理 ,研究了复合处理层的组织与性能特点。结果表明 :较之单一PECVDTiN ,离子渗氮 -PECVDTiN复合处理改善膜基界面结合 ,显著提高膜基结合强度与耐磨性 ;

工艺参数对PECVD TiN镀层性能的影响

本文考察了工艺参数对等离子体增强化学气相沉积(PECVD)TiN镀层性能的影响,并且研究了镀层的摩擦学性能与其物理机械性能及结晶学特征之间的关系。结果表明,当N/H比为1、Ti/N比为21、沉积温度为400℃和离化电压为1500V时,镀层具有较好的机械性能及耐磨性能。X—射线衍射分析表明,在本试验条件下所获镀层均为(200)面择优取向。作者指出,要制取理想的TiN镀层,离化电压应不低于1500V,沉积温度必须高于300℃。

等离子化学气相沉积(PCVD)TiN涂层的组织与性能研究

用透射电镜和X光衍射仪揭示了用PCVD法涂层TiN的物相及超细晶粒、位错、孪晶、择优取向等微观结构,并对该涂层的性能进行了比较试验。

在DC-PCVD阴阳极上沉积氮化硅薄膜

置于直流等离子体化学气相沉积（ＤＣＰＣＶＤ）装置的阴极或阳极的２０、２０Ｃｒ、ＧＣｒ１５及２Ｃｒ１３钢，以及单晶硅材料的试样均可沉积获得以Ｓｉ３Ｎ４成分为主要成分的非晶态的绝缘薄膜。这种膜有一定制作条件，讨论了阴阳极上试样都能获得这种膜的原因。

钢中含碳量对化学气相沉积TiN涂层的影响

在不同含碳量的钢基体上化学气相沉积TiN层,其沉积速度随基体含碳量增多而线性增大.TiN层的X射线衍射和扫描电镜能谱分析表明,除TiN衍射峰外,还有α Fe衍射峰。沉积温度升高,在Cr12MoV基体上TiN(220)面择优成长增加.TiN层表面白亮区和层内部只有Ti能谱,黑暗区则有Ti和Fe能谱。

划痕试验法测定TiN薄膜的粘着力

本文用划痕试验法研究了直流等离子体化学气相沉积(PCVD)镀膜工艺在高速钢、碳钢上沉积的 TiN 膜的剥落方式,测量了膜层被划干净时的临界载荷,并和 PVD、CVD 工艺在高速钢、硬质合金钢上镀的 TiN 膜作了比较,结果表明:PCVD 法较 PVD 法镀的 TiN 膜的粘着力强,达到了 CVD 法镀的 TiN膜的粘着力。