PECVD法制备硅化钛膜的工艺研究

硅化钛薄膜由于电阻率低和其它一些良好特性,在VLSI的栅电极和互连线中显示出它潜在的优势。本文研究了用PECVD法制备硅化钛膜的卫艺。结果表明:所形成硅化钛膜的性质强烈地依赖于淀积工艺条件。还确定了典型工艺条件,并用俄歇电子能谱分析了硅化钛膜的组分。     

高温退火对PECVD硅化钛膜的影响

<正> 一、引言 以TiSi_2为代表的难熔金属硅化物,由于具有铝及掺杂多晶硅所不具备的特点,已成为VLSI中制作栅电极和互连线的重要材料。CVD法制备硅化钛膜的突出优点是台阶覆盖性好,有利于批量生产。然而,用卧式PECVD制备硅化钛膜的方法至今尚未见报道。 PECVD法淀积的硅化钛膜,必须经退火结构才能稳定。目前,常用瞬态退火和常规热退火(高温退火)两种方法。常规热退火能和常规工艺兼容,而瞬态退火则可减少原子的互扩散。 笔者用平板型PECVD设备,在典型工艺条件下淀积了薄膜,分析了高温退火对薄膜电阻率、组分、结构的影响。     

光诱导化学汽相淀积非晶硅薄膜及其在太阳电池中的应用

本文较系统地评述了光诱导化学汽相淀积(LCVD)技术淀积非晶硅薄膜的开发现状,主要介绍了LCVD淀积非晶硅薄膜 的机理.评价了LCVD淀积非晶硅薄膜的电学和光学特性,最后介绍了这种薄在制备晶硅太阳电池方面的应用.     

氨气预氮化制备超薄氮化硅薄膜及电学性能

为寻求制备性能良好的纳米厚度氮化硅(SiN_x)薄膜的方法,采用NH_3等离子体氮化、SiH_4/NH_3等离子增强化学淀积法及先氮化后淀积的方法制备了三种SiN_x薄膜,研究比较了三种薄膜的性质。用X射线光电子谱检测了NH_3等离子体氮化Si片得到的SiN_x薄膜的组分,利用椭圆偏振光谱仪测量薄膜厚度,估算了氮化速率。用NH_3和SiH_4作为反应气,分别在原始硅片和经过NH_3预氮化后的硅片上淀积厚度为5 nm、10 nm和50 nm的SiN_x薄膜。用电容-电压法研究了薄膜样品的电学性质,发现单纯用NH_3等离子体氮化的薄膜不适合做介质膜,而先用NH_3氮化再淀积SiN_x的样品比直接淀积SiN_x的样品界面性能明显改善,界面态密度降低到1～2×10~(11)eV~(-1) cm~(-2)。     

LPCVD多晶硅膜的制备和在硅化铂肖特基势垒红外电荷耦合器件(PtSi-SBIRCCD)中的应用

本文介绍热壁低压化学汽相淀积(LPCVD)制备多晶硅膜的淀积变量,影响膜层质量的因素。其次简述了多晶硅膜的等离子刻蚀情况及其在硅化铂肖特基势垒红外电荷耦合器件(Ptsi-SBIRCCD)研制中的应用。     

等离子增强化学汽相淀积a-SiC:H簿膜的AES研究

用俄歇电子能谱(AES)对等离子增强化学汽相淀积(PECVD)氢化非晶碳化硅(a-SiC∶H)薄膜进行了组分的深度剖析、半定量分析以及化学分析.俄歇深度剖析曲线表明PECVD淀积的薄膜均匀性非常好;用俄歇半定量结果比较了薄膜成分同淀积工艺参量之间的一些关系;根据实验获得的Si LVV和CKLL俄歇谱比较和讨论了不同[Si]/[C]浓度比薄膜的化学特征.     

反应脉冲激光淀积硫化铅膜的SEM和XPS研究

以扫描电镜和Ｘ射线光电子能谱等多种测试手段研究分析了用反应脉冲激光淀积技术制备的ＰｂＳ薄膜。分析结果表明，利用该淀积方法可以得到附着力好，符合化学计量比的硫化铅薄膜。     

脉冲激光沉积薄膜专家系统

脉冲激光淀积技术是制备薄膜的先进技术之一,具有膜成分容易做到与靶成分一致、便于控制淀积条件、适用面宽、淀积速率高、易于引入新技术等特点.为了使脉冲激光淀积技术智能化、简便化,研究开发出了"脉冲激光淀积薄膜专家系统".该专家系统具有薄膜基片选择、淀积参数确定、实验结果总结、相关数据查询等功能.本文首先阐述了该专家系统的设计思想和工作原理,然后介绍了该专家系统的功能和结构;最后对该专家系统的适用条件和进一步拓展的目标进行了讨论.利用该专家系统,成功地指导了掺钛氧化钽薄膜和钛酸锶钙薄膜的制备.(OH16)     

高衬底温度下溅射淀积二硅化钛膜

我们在室温和600℃下用复合的二硅化钛靶在〈111〉向的裸硅片上溅射淀积了二硅化铁膜。室温下淀积的二硅化钛膜需要在900℃下进行烧结,以使其电阻率降低。而600℃下淀积的二硅化钛膜已经反应充分形成颗粒较大的没有氧沾污的多晶状,而且该膜抗氧化。将该膜在900℃下进行进一步退火,发现其晶体结构、成分、电阻率即晶粒大小没有变化。     

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。     

Selective deposition of TiSi2 on oxide patterned wafers using low pressure chemical vapor deposition

The selective deposition of titanium disilicide was investigated using a cold-wall, low pressure chemical vapor deposition (LPCVD) technique with silane and titanium tetrachloride as the silicon and titanium sources, respectively. In-situ hydrogen plasma effectively cleaned the silicon wafer surface for deposition of C54 TiSi₂ at 760‡ C with full selectivity. A new method using a plasma only at the beginning of the deposition of the silicide further decreased the temperature to 680‡ C without losing selectivity. The result was a fine grained film probably due to the enhanced nucleation rate of the silicide. Cross-sectional TEM studies showed that the silicide grew into the silicon substrate, suggesting significant silicon consumption. The silicon substrate, consequently, seems to play a major role in the silicide formation. Silane, on the other hand, plays a minor role as a silicon source but does act as a scavenger of HC1 in the gas or on the silicide surface.     

Noncontacting measurement of thickness of thin titanium silicidefilms using spectroscopic ellipsometer

Spectroscopic ellipsometry has gained increasing attention in semiconductor process control because the technique is nondestructive and noncontacting. This paper demonstrates the capability of spectroscopic ellipsometer to measure the thickness of conducting thin films of titanium silicide. Unlike cross section TEM measurement, this technique does not involve elaborate process of sample preparation. This technique does not require calibration and is used to determine thickness of silicide films from few tens of angstrom up to tens of nanometer. The thickness of titanium silicide film measured at a single point, using spectroscopic ellipsometer and TEM analysis differs by only 4%     

Titanium silicide-silicon interface degradation during heat treatment

Thin titanium silicide films were grown on different silicon substrates by rapid thermal annealing in a nitrogen ambient. The silicide films were then annealed in a furnace at high temperature in a nitrogen ambient for various times. The effect of such heat treat-ment on the morphology of titanium silicide surface and the titanium silicide-silicon interface was studied. It is proposed that the morphological change is primarily due to the diffusion of silicon and/or dopant impurities via grain boundaries of the silicide. There is a strong correlation between the surface of the titanium silicide film and that of the titanium silicide-silicon interface.     

Structural and electrical properties of furnace and rapid thermallyannealed LPCVD WSi2 films on single-crystal, polycrystalline,and amorphous silicon substrates

Alternate approaches to obtain low-resistance, low-pressure chemical vapor deposition (LPCVD) WSi₂ films for application as interconnections in silicon integrated circuit technologies were investigated. The silicide films were deposited on three different substrates and annealed in two different systems. The silicide films deposited on the doped substrates as well as films doped using ion implantation were analyzed. The silicide microstructure, electrical film conductivity, and dopant redistribution were studied as a function of the process variants. An optimum set of annealing conditions were identified that resulted in excellent silicide thin-film properties. A correlation between the material and electrical properties is provided using the experimental data     

用ECRC-VD方法制备非晶氟化碳薄膜

以C4F8为源气体,Ar为稀释气体,用电子回旋共振化学汽相淀积的方法制作了非晶氟化碳薄膜;使用XPS和FTIR分析薄膜的化学组分和成键类型;研究了微波功率对于沉积速率和薄膜光学性质的影响。沉积速率随Ar在混合气体中比例的增大先增大后降低,随微波功率的增加而增加,并最终趋于饱和值。沉积的薄膜介电常数约为2.0,在可见光区薄膜具有良好的透光性。在较高的微波功率条件下,沉积薄膜的光学带隙减小。     

Influence of the fabrication conditions of polymorphous silicon films on their structural, electrical and optical properties

The structural, optical, and photoelectric properties of polymorphous silicon films produced by plasma-enhanced chemical vapor deposition from a mixture of monosilane and hydrogen at high pressure are studied. Variations in the pressure of the gas mixture used for film production barely change the Raman spectra of the films, but induce changes in the photoconductivity and in the absorption spectrum obtained by the constant-photocurrent technique. The experimentally observed change in the optical and photoelectric parameters of the films is attributed to some structural changes induced in the films by variations in the deposition parameters.     

Low temperature plasma enhanced chemical vapor deposition of silicon oxide films using disilane and nitrous oxide

Silicon oxide films have been deposited between room temperature and 300°C using disilane and nitrous oxide by plasma enhanced chemical vapor deposition. Film deposition was investigated as a function of the gas flow ratio of nitrous oxide to disilane, the substrate temperature, the total gas flow rate, the radio frequency discharge power, and the process pressure. The stoichiometric SiO₂ films were obtained when the gas ratio of nitrous oxide to disilane was in the range of 50-150. The deposition was found to be nearly temperature independent indicating the mass transport limited regime.     

Nonempirical simulation of chemical deposition of silicon nitride films in CVD reactors

This work is devoted to the atomistic simulation of chemical vapor deposition (CVD) of thin silicon nitride films from the mixture of dichlorosilane (DCS) and ammonia in CVD reactors. The earlier developed chemical mechanism is substantially extended by including the reactions of catalytic decomposition of DCS, and a self-consistent atomistic model of a CVD process is developed. An extended chemical mechanism is constructed and analyzed that allows one to adequately describe kinetic processes in a gas phase within the ranges of temperature, pressure, and the DCS: NH₃ ratio of original reactants, that are characteristic of silicon nitride deposition. An effective kinetic model is developed that involves the calculation of the rate constants and the concentrations of the gas mixture components. A thermodynamic analysis of the surface coverage by various chemisorbed groups is carried out, and equilibrium surface concentrations are obtained for the main chemisorbed groups. Practically significant conclusions are made about the character of the deposition process and, in particular, about the role of the extended chemical mechanism.     

Processing and characterisation of PECVD silicon nitride films

Amorphous Si-N films are synthesised from an NH₃/SiH₄ gas mixture by plasma-enhanced chemical vapour deposition (PECVD) at fixed radio frequency (13.56 MHz) and total gas pressure (34 ± 4 Torr). The variable process parameters and their ranges are: (i) substrate temperature, 200–400°C; (ii) RF power density, 0.08–0.35 W cm⁻²; (iii) NH₃/SiH₄ flow ratio, 40:400–40: 1200 ml min⁻¹. Fundamental properties of the Si-N films are characterised through elemental composition, chemical speciation, optical and electrical properties, all of which are dependent on the process parameters.