低应力PECVD氮化硅薄膜的制备

研究了等离子增强化学气相淀积(PECVD)工艺中射频条件(功率和频率)对氮化硅薄膜应力的影响.对于不同射频条件下薄膜的测试结果表明:低频(LF)时氮化硅薄膜处于压应力,高频(HF)时处于张应力,且相同功率时低频的沉积速率和应力分别为高频时的两倍左右;在此基础上采用不同高低频时间比的混频工艺实现了对氮化硅薄膜应力的调控,且在高低频时间比为5:1时获得了应力仅为10 MVa的极低应力氮化硅薄膜.     

管式PECVD射频功率对氮化硅薄膜性能的影响

氮化硅薄膜作为传统的晶体硅太阳电池钝化减反膜,其性能的变化直接影响电池的转化效率。通过改变管式PECVD的射频功率,制备了不同膜厚和折射率的氮化硅薄膜,并分别进行了薄膜致密性以及硅片镀膜后少子寿命的测试。实验及测试结果表明,改变PECVD的射频功率对氮化硅薄膜的沉积速率及其薄膜的性能有重要影响。     

应用高频激励源制备低应力氮化硅薄膜研究

研究了在等离子体增强化学气相沉积(PECVD)法制备氮化硅薄膜时,射频功率和腔室压力对氮化硅薄膜应力的影响以及应力与沉积速率的关系。通常认为高频下制备得到的氮化硅膜呈现张应力,但是通过实验,表明即使应用高频(13.56MH z)作为激励源同样可以沉积出呈现压应力的氮化硅薄膜。并使用角度可变光谱型椭偏仪观察了薄膜的厚度和低应力氮化硅膜的m app ing图,利用傅立叶变换红外光谱仪(FT IR)对不同应力状态下的氮化硅膜的化学键结构进行了分析。     

低压化学气相沉积制备低应力氮化硅膜的研究

采用低压化学气相沉积方法，通过改变工艺气体配比，在硅衬底上生长低应力氮化硅薄膜。用应力仪、椭偏仪对生成的氮化硅薄膜的应力、生长速率、均匀性、折射率及腐蚀速率等进行实验。实验结果表明：低应力氮化硅薄膜制备的关键是增大DCS和NH₃的配比，配比越大，生成的氮化硅薄膜应力越小，折射率越大，耐酸腐蚀能力越强，致密性越好；但随着配比增大，生成的氮化硅薄膜均匀性变差。选择合适的工艺气体配比可在硅衬底上制备出高质量的低应力氮化硅薄膜。     

真空退火对低频PECVD氮化硅薄膜性能的影响

研究了真空退火温度对不同流量比工艺参数下PECVD氮化硅薄膜性能的影响,测试了退火后氮化硅薄膜厚度、折射率以及在氢氟酸中的腐蚀速率。结果表明,退火后氮化硅薄膜厚度及折射率变化与薄膜沉积工艺条件有关,而薄膜在氢氟酸中的腐蚀速率在退火后大大降低。结合退火前后氮化硅薄膜的红外透射谱对以上测试结果进行了讨论。     

淀积参数对PECVD氮化硅薄膜力学特性的影响

等离子增强化学气相淀积(PECVD)法制备的氮化硅薄膜具有沉积温度低、生长速率高和残余应力可调节等特点,研究其力学特性对研制MEMS器件和系统具有重要意义。采用HQ-2型PECVD淀积台,在沉积温度为350℃,NH3流量为30cm3/min的条件下,通过改变氩气稀释至5%的SiH4流量和射频功率大小,制备了具有压应力、微应力和张应力的多种氮化硅薄膜样品。采用纳米压痕仪Nanoidenter-G200对淀积薄膜的杨氏模量和硬度进行测试,结果表明,在较小的SiH4流量和较高的射频功率条件下,淀积的氮化硅薄膜具有更高的杨氏模量和硬度。     

GaAs衬底上氮化硅钝化层的低温制备工艺研究

为了获得应用于AlGaAs激光器上的优异的氮化硅薄膜,采用等离子增强化学气相沉积(PECVD)低温条件下在GaAs衬底上制备了不同参数的氮化硅薄膜,利用光学膜厚仪、原子力显微镜(AFM)、傅里叶变换红外光谱(FTIR)等技术对薄膜残余应力、表面形貌、折射率等进行了分析。结果表明,薄膜的残余应力随沉积功率的增加而变大;随气压先降低后变大,在200 Pa时仅为6 MPa。薄膜的表面粗糙度随功率的提高而变大;随气压的提高而减小。功率和气压对薄膜的折射率影响不大,均在2.0~2.2之间。薄膜中氢的存在形式为N-H键。选择合适的功率和气压,可以在低温下获得极低应力和优异表面形貌的氮化硅薄膜。     

PECVD法氮化硅薄膜生长工艺的研究

采用等离子体增强化学气相沉积法(PECVD),在单晶硅衬底(100)上成功制备了不同生长工艺条件下的氮化硅薄膜。分别采用XP-2台阶仪、椭圆偏振仪等手段测试了薄膜的厚度、折射率、生长速率等参数。并采用原子力显微镜(AFM)研究了薄膜的表面形貌。结果表明,温度和射频功率是影响薄膜生长速率的主要因素,生长速率变化幅度可以达到230nm/min甚至更高。对于薄膜折射率和成分影响最大的是NH3流量,折射率变化范围可以达到2.7～1.86。分析得出受工艺参数调控的薄膜生长速率对薄膜的性质有重要影响。     

氮化硅在触摸屏中的应用分析(英文)

研究了氮化硅材料在触摸屏领域中的应用,利用等离子体化学气相沉积技术,在一定厚度的玻璃表面沉积不同厚度的氮化硅薄膜。通过理论分析和试验测试的方法得到了氮化硅膜层厚度和折射率对触摸屏透过率以及表面宏观颜色的影响。分析结果表明,氮化硅膜层折射率对触摸屏的平均透过率影响明显,而膜层厚度对触摸屏的平均透过率影响很小,但是膜层厚度的改变对触摸屏特定波长处透过率和膜层宏观颜色影响很明显。在实际生产中可以通过改变沉积条件获得合适折射率及厚度的氮化硅薄膜材料。     

压电型微悬臂梁制备中RIE刻蚀硅工艺的研究

介绍了一种压电型微悬臂梁的制作工艺流程,重点研究了其中硅的反应离子刻蚀(RIE)工艺,分析了工艺参数对刻蚀速率、均匀性和选择比的影响,提出通过适当调整气体流量、射频功率和工作气压,以加快刻蚀速率,改善均匀性,提高选择比。研究表明,在SF6流量为20 mL/min,射频功率为20 W,工作气压为8.00 Pa的工艺条件下,硅刻蚀速率可以提高到401 nm/min,75 mm(3 in.)基片范围内的均匀性为±3.85%,硅和光刻胶的刻蚀选择比达到7.80。为制备压电悬臂梁或其它含功能薄膜的微结构提供了良好的参考。     

微波ECR等离子体中的电子能量吸收的计算

本文研究了ＥＣＲ系统中微波能量的耦合过程，给出了电子能量吸收的数值计算，发现ＥＣ共振腔内静磁场的分布、工作气压和微波功率是决定产生高能电子的主要因素，从而决定了ＥＣＲＣＶＤ薄膜淀积工艺的有关参数。进行了ＥＣＲＣＶＤＳｉＮ薄膜的工艺实验，其结果与理论计算符合得较好。     

Impacts of SiN deposition parameters on n-channel metal-oxide-semiconductor field-effect-transistors

Although the incorporation of a SiN capping layer could dramatically enhance device performance, the accompanying hydrogen species contained in the capping layer may aggravate hot-carrier reliability. In order to alleviate this shortcoming, we vary the precursor flow conditions and deposition temperature of SiN film during plasma-enhanced chemical vapor deposition (PECVD) and study their impacts on the device performance and reliability. We found that SiN film with higher nitrogen content depicts larger tensile stress and therefore better mobility. More importantly, the resistance to hot-carrier degradation is also improved by increasing N₂ gas flow rate and deposition temperature because of less hydrogen diffusion from the capping layer.     

晶体硅太阳电池减反射膜的研究

在太阳电池表面形成一层减反射薄膜是提高太阳电池的光电转换效率比较可行且降低成本的方法。应用PECVD（等离子体增强化学气相沉积）系统,采用SiH4和NH3气源以制备氮化硅薄膜。研究探索了PECVD生长氮化硅薄膜的基本物化性质以及在沉积过程中反应压强、反应温度、硅烷氨气流量比和微波功率对薄膜性质的影响。通过大量实验,分析了氮化硅薄膜的相对最佳沉积参数,并得出制作减反射膜的优化工艺。     

CeO_2高K栅介质薄膜的制备工艺及其电学性质

研究了 Ce O2 作为高 K (高介电常数 )栅介质薄膜的制备工艺 ,深入分析了衬底温度、淀积速率、氧分压等工艺条件和利用 N离子轰击氮化 Si衬底表面工艺对 Ce O2 薄膜的生长及其与 Si界面结构特征的影响 ,利用脉冲激光淀积方法在 Si(10 0 )衬底生长了具有 (10 0 )和 (111)取向的 Ce O2 外延薄膜 ;研究了 N离子轰击氮化 Si衬底表面处理工艺对 Pt/ Ce O2 / Si结构电学性质的影响 .研究结果显示 ,利用 N离子轰击氮化 Si表面 /界面工艺不仅影响 Ce O2 薄膜的生长结构 ,还可以改善 Ce O2 与 Si界面的电学性质     

淀积条件对a-SiNx:H薄膜中含氢基团的影响

利用红外光谱研究了等离子体化学气相沉积（ＰＥＣＶＤ）方法淀积的ａ－ＳiＮｘ：Ｈ薄膜。分析了气体流量比（Ｒ）、衬底温度（Ｔｓ）以及射频功率（Ｐ(ｒｆ)）的变化对ａ－ＳｉＮｘ：Ｈ薄膜中ＳｉＨ、ＮＨ和ＮＨ２基团的吸收峰强度的影响,同时研究了退火条件对ａ－ＳｉＮｘ：Ｈ薄膜中含氢基团的影响。     

Optimization of SiN AR coating for Si solar cells and modules through quantitative assessment of optical and efficiency loss mechanism

Plasma‐enhanced chemical vapor deposition (PECVD) SiN films are widely used as antireflection (AR) coating for silicon solar cells and particularly for multi‐crystalline solar cells for hydrogen passivation of bulk defects. In this paper, the detailed optical properties of various SiN films and their effect on silicon solar cell efficiency in air and under glass is evaluated by a combination of Monte‐Carlo geometrical ray tracing program, Sunrays, and a device modeling program PC1D. Maximum module power under glass and ethylene vinyl acetate (EVA) encapsulation is used as the figure of merit for optimizing the index and thickness of the SiN films. Simulations are categorized by surface morphology (planar or textured) and ambient (air or glass). SiN films with refractive index (n) in the range of 2.03–2.42 are used for this study. It is found that although n = 2.03 is not the optimum index in terms of reflectance under glass (n = 1.5), it produces maximum cell or module efficiency under glass. This is because n = 2.03 film produces much higher cell efficiency (17.9%) in air, therefore, even after a significant optical encapsulation loss of 0.8% in absolute efficiency, the cell efficiency remains highest (17.1%) under glass. In contrast SiN film with an index of 2.4 produces only 0.5% air to glass efficiency loss but due to the low starting efficiency of 17% in air; the final cell efficiency under glass is only 16.5%. In addition, texturing provides a larger window of thickness around the optimum without affecting the optical performance. Similar analysis done for planar cells indicate that optimum index for highest module power is 2.20. This is because reflection is much higher in planar cells, therefore higher index can be tolerated before loss due to absorption in SiN exceeds the gain in reflectance under glass. Copyright © 2011 John Wiley & Sons, Ltd.     

Atomic force microscopy (AFM) and X-ray diffraction (XRD) investigations of copper thin films prepared by dc magnetron sputtering technique

This paper addresses the influences of sputtering power and deposition pressure on the surface morphology and structural behavior of dc magnetron sputter-deposited copper (Cu) thin films on p-type silicon grown at room temperature. Results from our experiments show that the deposition rate of the Cu film increases proportionally with the sputtering power and decreases with deposition pressure. From the atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis, high sputtering power enhances the microstructure of the Cu film through the surface diffusion mechanism of the adatom. The poor microstructure as a result of low sputtering power deposition was manifested with the smaller value of Cu film root mean square (RMS) roughness obtained. The deposition pressure has the contrary influence on structural properties of Cu film in which high deposition pressure favors the formation of voided boundaries film structure with degraded film crystallinity due to the shadowing effect, which varies with different deposition pressures.     

Effects of Ar ion assisted deposition on the optical and electrical characteristics of electron-beam-evaporated amorphous Si films

In this paper,the effects of Ar ion bombardment during the electron beam evaporation deposition of the amorphous Si film were investigated. It was found that the bombardment increases the light absorption by two to eleven times and increases the conductance of the film by 3 000 times, This has never been reported before of amorphous Si with electron beam evaporation deposition.     

Improved reliability of AlGaN-GaN HEMTs using an NH/sub 3/ plasma treatment prior to SiN passivation

A passivation method has been developed which reduces the degradation of AlGaN-GaN high electron mobility transistor (HEMT) electrical properties caused by extended dc bias or microwave power operation. The key aspect of this passivation technique is exposure to a low-power NH/sub 3/ plasma prior to SiN deposition. Devices fabricated with the NH/sub 3/ treatment prior to SiN passivation show minimal gate lag and current collapse after extended dc bias operation. In addition, the rate of degradation of the microwave power output while under continuous microwave operation is improved by at least 100 times as compared to SiN passivated HEMTs that were not treated with the NH/sub 3/ plasma.