PECVD SiO2 薄膜内应力研究

研究了等离子体增强化学气相淀积(PWCVD)法生长SiO2薄膜的内应力.借助XP-2型台阶仪和椭偏仪测量计算了SiO2薄膜的内应力,通过改变薄膜淀积时的工艺条件,如淀积温度、气体流量、反应功率、腔体压力等,分析了这些参数对SiO2薄膜内应力的影响.同时讨论了内应力产生的原因以及随工艺条件变化的机理,对工艺条件的优化有一定参考价值.     

LPCVD制备二氧化硅薄膜工艺研究

采用TEOS源LPCVD法制备了SiO2薄膜,采用膜厚仪对薄膜的厚度进行测试.通过不同条件下SiO2薄膜的厚度变化,讨论了TEOS源温度、反应压力及反应温度等工艺条件对淀积速率和均匀性的影响.结果表明,在40℃,50 Pa左右,淀积速率随TEOS源温度、反应压力基本呈线性增大.通过多次试验改进,提出了SiO2膜淀积的典...     

SiN钝化对InGaAs/InP双异质结双极性晶体管直流性能的影响

研究了SiN钝化对InGaAs/InP双异质结双极性晶体管(DHBT)直流性能的影响。在不同温度和不同气体组分条件下淀积了SiN薄膜,并对钝化器件的性能进行了测量和比较。结果表明,低的淀积温度有利于减小淀积过程对器件的损伤;采用氮气(N_2)和硅烷(SiH_4)取代常用的氨气(NH_3)和硅烷(SiH_4)作为淀积SiN薄膜的反应气体,显著地减少了器件发射结(B-E)和集电结(B-C)泄漏电流。另外,与未钝化器件的直流性能相比,钝化后器件的电流增益增加,基区表面复合电流大幅减小,这对提高器件的可靠性至关重要。     

蒸发膜薄应力问题探讨

<正> 从事薄膜工艺和薄膜元件研究的人,应该对薄膜结构、生长机理和机械效应作一些基本研究,以利更好地解决薄膜元件的长期稳定性和失效问题。 薄膜的总应力由热应力和内应力组成。内应力又分为生长过程产生的淀积内应力和淀积后引入的附加内应力。影响薄膜应力的因素很多,其机理十分复杂。在认识薄膜     

低温下氮化硅膜的制备及特性的分析研究

本文阐述了等离子增强化学汽相淀积(PECVD)氮化硅膜的生长原理和方法;对于在不同衬底,如Si,特别是GaAs和金属膜上淀积氮化硅膜的各种影响因素进行了理论和实验分析;针对GaAs上淀积氮化硅膜的特殊现象提出了新的解释;推导出了SiN膜性能参数Si/N、折射率、Si-H键和N-H键密度等量之间关系的经验公式;研完了MNM电容上下电极对SiN性能的影响,指出用Ti-Pt-Au做下电极,Al做上电极可以提高电容耐压;确立了优化的条件,在较低温度(200～300℃)下生长出了氧含量极低、致密耐击穿电压高的优质SiN膜,该介质膜实用于半导体单片集成电路和高耐薄膜电容。     

PECVD SiN及其在GaAs MESFET中的应用——第1部分:PECVD SiN的制备及其组分和键结构

叙述了PECVD SiN的制备、性能及其在GaAs场效应器件中的应用。第一部分叙述PECVD SiN的一般概念、设备及淀积条件,阐明其键结构以及它们与工艺条件的关系。第二部分叙述PECVD SiN性能及其与工艺条件的关系,着重叙述在GaAs器件中的应用和对器件性能的影响。     

低温光CVD—SiO2及SiN薄膜的研究

本文介绍了在低温(50～200℃)条件下,用光CVD技术制备SiO_2及SiN薄膜的工艺方法.讨论了某些工艺参数与薄膜性质的一些关系,并对光CVD-SiO_2及SiN薄膜的物理性质和电气性质进行了全面的分析.结果表明,这种低温光CVD薄膜在半导体器件工艺中将有广泛的应用.     

用于应变硅技术的高应力SiN薄膜的开发

在高级CMOS器件中,高应力氮化硅(SiN)薄膜是增强应变的主要方法。如果要改善PMOS或NMOS器件性能,则分别需要采用具有压应力和张应力的氮化硅薄膜。我们对相关机理进行了回顾,根据不同的淀积和工艺处理条件的组合,从而得到了张应力大于1．6 GPa和压应力大于2．9GPa的氮化硅薄膜覆盖。     

p-Si TFT栅绝缘层用SiN薄膜的研究

以NH3和SiH4为反应源气体,采用射频等离子体增强化学气相沉积(RF-PECVD)法在多晶硅(p-Si)衬底上沉积了一系列SiN薄膜,并利用椭圆偏振测厚仪、超高电阻-微电流计、C-V测试仪对所沉积的薄膜作了相关性能测试.系统分析了沉积温度和射频功率对SiN薄膜的相对介电常数、电学性能及界面特性的影响.分析表明,沉积温度和射频功率主要是通过影响SiN薄膜中的Si/N比影响薄膜的性能,在制备高质量的p-Si TFT栅绝缘层用SiN薄膜方面具有重要的参考价值.     

PECVD法低温形成纳米级薄介质膜击穿特性的实验研究

对等离子体增强化学汽相淀积(PECVD)法制成纳米级SiOxNy薄膜组成的MIS结构样品,通过美国HP系列设备测试I-V特性、准静态及高频C-V特性.分析了薄膜I-V特性、击穿机理与各项电学性能;探讨了膜的击穿电场等电学参数以及击穿电场随反应室气压、混合气体比例、衬底温度的变化关系;给出了击穿等电性优良的PECVD形成SiOxNy薄介质膜的优化工艺条件.     

Analysis of LPCVD process conditions for the deposition of low stress silicon nitride. Part I: preliminary LPCVD experiments

A wide range of process conditions were investigated to optimize conditions for the deposition of low stress silicon nitride films by low-pressure chemical vapor deposition. Experiments carried out in a standard, multi-wafer batch system generated films with an index of refraction ranging from about 2.04 to 2.82 and residual stress ranging from about 700 MPa tensile to –90 MPa compressive. The relationship between residual stress and index of refraction was characterized and results compared to those presented in the technical literature. Increase in the index of refraction beyond about 2.3 by means of increasing the gas flow did not reduce the residual stress appreciably but had a significant detrimental impact on the thickness uniformity and deposition rate. In contrast to results reported by other researchers, uniformity was not observed to increase with increasing DCS/NH₃ ratio in this study. Efforts to minimize thickness non-uniformity by suppressing deposition rate at the gas inlet region of the deposition system while increasing deposition rate at the rear were not successful. While increasing the temperature at the exhaust end of the system was intended to improve thickness non-uniformity, significant thickness and index of refraction uniformity was not realized. The reduction in deposition rate and corresponding increase in index of refraction at the exhaust end of the system indicated a variation in gas species from inlet to exhaust of the system. These experimental results revealed that the index of refraction decreased while the deposition rate decreased with increasing partial pressure of DCS. This suggests that the inhomogeneity observed within the repeatability runs is due to ammonia depletion along the length of the load.     

制备工艺条件对薄膜微结构的影响

用不同的方法在石英玻璃,YAG晶体,K9玻璃和LiNbO3晶体等几种衬底上制备了ZrO2,HfO2和TiO2薄膜。HfO2薄膜利用电子束蒸发(EB)、离子束辅助(IAD)和双束离子束溅射(DIBS)三种方法沉积。对其中的一些样品进行了不同温度下的退火处理,对所有的样品进行X射线衍射(XRD)测试,以获得不同条件下得到的薄膜的晶相及晶粒尺寸等的微结构参数。实验结果表明,薄膜的晶相结构以及晶粒尺寸强烈地依赖于沉积过程的各种技术参数,如衬底的种类、沉积温度、沉积方法和退火温度。利用薄膜表面扩散以及薄膜成核长大热力学原理解释了不同技术条件下的晶相结构和晶粒尺寸不同的原因。     

Characteristics of the NO dielectric film with low pressure chemical vapor deposition in-situ nitridation

We investigated the formation of the thin NO dielectric films by in-situ nitridation of native oxide, and subsequent deposition of silicon nitride in the low pressure chemical vapor deposition systems for the application to the capacitors in high density dynamic random access memory. The native oxide was nitrided at elevated temperatures of 690 or 780°C in the flowing ammonia gas atmosphere, and nitride was deposited by flowing silane gas additionally immediately after the nitridation process. By in-situ nitridation process, we could obtaine 5 and 4.5 nm thick (equivalent oxide thickness) nitride/oxide (NO) dielectric films. These films were characterized to be electrically more reliable than the conventional oxide/nitride/oxide (ONO) films of the same equivalent oxide thickness. The nitrided NO films also showed lower leakage current and higher breakdown voltage than conventional ONO films. We obtained electrically most reliable NO films by loading the wafer at 400°C and nitriding the native oxide at 780°C.     

Semi-empirical neural network modeling of metal-organic chemicalvapor deposition

Metal-organic chemical vapor deposition (MOCVD) is an important technique for growing thin films with various applications in electronics and optics. The development of accurate and efficient MOCVD process models is therefore desirable, since such models ran be instrumental in improving process control in a manufacturing environment. This paper presents a semi-empirical MOCVD model based on “hybrid” neural networks. The model is constructed by characterizing the MOCVD of titanium dioxide (TiO₂) films through the measurement of deposition rate over a range of deposition conditions by a statistically designed experiment in which susceptor and source temperature, flow rate of the carrier gas for the precursor and chamber pressure are varied. A modified backpropagation neural network is then trained on the experimental data to determine the value of the adjustable parameters in an analytical expression for the TiO₂ deposition rate. In so doing, a general purpose methodology for deriving semi-empirical neural process models which take into account prior knowledge of the underlying process physics is developed     

用ECRCVD法制备的纳米碳化硅薄膜及其室温下的强光发射

用电子回旋共振化学气相沉积(ECRCVD)方法制备了纳米碳化硅薄膜.实验中发现:在高氢稀释反应气体和高微波功率条件下,可以得到结构上具有纳米碳化硅晶粒镶嵌在碳化硅无序网络中的薄膜.用高分辩透射电子显微镜、傅里叶红外吸收谱、Raman散射和X射线光电子谱等分析手段对薄膜的结构进行了分析.在室温条件下,薄膜能够发出强烈的短波长可见光,发光峰位于能量为2.64eV处.瞬态光谱研究表明样品的光致发光寿命为纳秒数量级,表现出直接跃迁复合的特征.这种材料有希望在大面积平面显示器件中得到应用.     

Stress development during evaporation of Cu and Ag on silicon

This work presents results of stress measurements during deposition of thin silver and copper films on 100 μm Si substrate. The stress in thin films has been determined by means of an optical system for the measurement of sample’s curvature. This system was applied in situ in a high vacuum deposition system. For Ag films the stress occurring during deposition goes from a low compressive value to tensile for thickness less than 30 nm and to compressive above this. For Cu films we observe tensile stress for thickness less 20 nm and above 50 nm. The same general trend of stress evolution with thickness is present in all cases at initial stage. There is the same growth mode for Cu and Ag because of the similar shapes of stress curves for thickness lower than 30 nm The behavior of stress evolution was explained by island nucleation and growth, island coalescence and continuous film growth. The difference in the stress evolution above 30 nm is caused by the fact that silver may be less sensitive than copper to adsorption of impurities. Adsorbed contamination inhibits compressive stress increase generated by grain boundary and defects remaining in the film.     

应用于射频范围的软磁薄膜研究进展

探讨了获得具有优良高频电磁性能的软磁薄膜的合适工艺条件。指出薄膜的性能主要取决于薄膜的成分、微观组织、磁致伸缩系数、残余应力状态、有无软磁底层、外加磁场溅射沉积和后续磁场热处理等因素。以Fe70Co30为基的软磁薄膜和Fe(Co)-X-N纳米晶软磁薄膜主要应用于要求高饱和磁化强度的器件如磁头中,磁性纳米颗粒膜具有高的电阻率因而趋肤深度较大,有望应用于高频微磁器件如微电感、微变压器的磁芯中。     

Pulsed DC magnetron sputtering deposition of crystalline photocatalytic titania coatings at elevated process pressures

The use of elevated process pressures is described in the magnetron sputter deposition of titanium dioxide photocatalytic coatings to enable the direct low-temperature formation of the most photoactive titania crystal phase; anatase. Most other works on this subject deal with relatively low ‘conventional’ pressures (0.1–0.5 Pa). However, the present work describes pulsed DC reactive magnetron sputtering deposition of titanium dioxide thin films at process pressures in the range 2–5 Pa in a purpose-built sputtering rig. The influence of the other deposition conditions, such as pulse frequency and duty cycle, is also discussed. Additionally, a series of N-doped titania coatings was produced by using air as the reactive gas. The morphological and compositional properties of the coatings were studied using energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Wettability of the films was studied through measurement of water contact angles under UV light irradiation. Photocatalytic properties of the samples were assessed through the degradation of two model pollutants, methylene blue and stearic acid, under UV light irradiation. The results showed that elevated process pressures (4 Pa and above) allow the direct deposition of anatase titania films, without additional heat treatment, while amorphous titania tends to form at lower process pressures.     

太阳电池中CdS多晶薄膜的微结构及性能

采用化学水浴法制备了CdS多晶薄膜，通过XRD，AFM，XPS和光学透过率谱等测试手段研究了CdS多晶薄膜生长过程中的结构和性能.结果表明，随着沉积的进行，薄膜更加均匀、致密，与衬底粘附力增强，其光学能隙逐渐增大，薄膜由无定形结构向六方(002)方向优化生长，同时出现了Cd(OH)2相.在此基础上，通过建立薄膜的生长机制与性能的联系，沉积出优质CdS多晶薄膜，获得了转化效率为13.38%的CdS/CdTe小面积电池.