有机发光器件的低温氮化硅薄膜封装

利用等离子体化学气相沉积(PECVD)技术，采用不同的沉积条件(20—180℃的基板温度范围和10—30W的射频功率)制备了氮化硅薄膜，研究了沉积条件对氮化硅薄膜性质和防水性能的影响。实验发现随着基板温度的增加，氮化硅薄膜的密度、折射率和Si／N比相应增加，而沉积速率和H含量相应减少；随着射频功率的增加，氮化硅薄膜的沉积速率、密度、折射率和Si／N比相应增加，而H含量相应减少。水汽渗透实验发现即使基板温度降低为50℃，所沉积的氮化硅薄膜仍然具有良好的防水性能。实验结果表明低温氮化硅薄膜可以有效地应用于有机发光器件（OLED)的封装。     

非晶硅薄膜的沉积速率研究

利用PECVD方法在硅片上制备了非晶硅薄膜,通过正交实验得出影响薄膜沉积速率和折射率的主要参数为气体流量和射频功率,分别研究了这两个参数对沉积速率和折射率的影响.结果表明当气体流量低于240sccm时,薄膜沉积速率随气体流量增加而增加,而折射率则随之减小;当流量大于240sccm时,沉积速率出现饱和,折射率的变化并不明显.当射频功率低于120W时,薄膜沉积速率随着功率的提高而增大,而折射率则随之减小;当功率大于120W并进一步提高时,沉积速率成下降趋势,折射率则随之增大.     

HfO2薄膜的制备与光学性能

采用射频磁控反应溅射法，以高纯热压HfO2陶瓷为靶材，在Si衬底上成功制备出HfO2薄膜。系统研究了工艺参数对薄膜沉积速率的影响规律，并对薄膜的光学性能进行了研究。结果表明，射频功率对薄膜沉积速率的影响最为明显，O2／Ar流量比和衬底温度对沉积速率的作用不明显，所制备薄膜的折射率较高在近红外波段趋于1．95，在500-1650nm波段范围内薄膜几乎无吸收，透过率较高。     

Ge1-xCx薄膜的制备及红外特性的研究

利用等离子体化学气相沉积(PECVD)法制备出Ge1-xCx薄膜,并系统地研究了工艺参数对薄膜成分的影响,以及不同组分Ge1-xCx薄膜的红外光学特性.结果表明,薄膜中的C含量随着CH4/GeH4气体流量比的增大而增大;薄膜的红外折射率随组分的不同在2～4范围内变化;薄膜的沉积速率随射频功率增大而增大,但当功率达到60 W以后其变化不明显;沉积速率随温度的增加而减少;该薄膜具有透长波红外的性能.     

用等离子体增强化学气相沉积制备微晶硅薄膜

以Ar+SiH_4作为反应气体,用电子回旋共振等离子体化学气相沉积(ECR PECVD)方法制备微晶硅薄膜,研究了微波功率对薄膜中H含量、薄膜的沉积速率、择优取向和结晶度的影响。结果表明,在300℃制备低温微晶硅薄膜,随着微波功率的增大,薄膜的沉积速率先增大后减小,微波功率为600 W时达到最大;而结晶度和薄膜中的H含量则分别呈现单调增大和单调减少的趋势;使用不同的微波功率,薄膜的择优取向均为(111)方向。     

采用电子回旋共振微波等离子体增强的溅射沉积薄膜技术

利用高等离子体密度、高电子温度和高离化率的ECR微波等离子体增强二极溅射、磁控溅射反应沉积金属氨化物薄膜。实验结果表明，ECR微波等离子体具有降低薄膜沉积温度，提高薄膜沉积速率和改善薄膜质量的作用。特别是采用基片施加脉冲负偏压的ECR微波等离子体源离子增强反应磁控溅射沉积技术，设备成本低，工艺方法简单，可获得与离子束增强沉积（IBAD）相近的对薄膜结构和特性的改性作用，可制备高质量金属氢化物薄膜。     

磁控溅射法制备CdS多晶薄膜工艺研究

采用磁控法制备了CdS薄膜,研究工艺参数对样品沉积质量、沉积速率及晶体结构的影响。实验发现,在不同衬底上制备CdS薄膜时需要采取不同的后续工艺措施以获得较好的沉积质量。同时,制备样品的沉积速率随衬底类型、衬底温度、溅射功率及溅射气压的变化而变化。讨论并给出了工艺参数对上述实验结果的影响机制。X射线衍射谱显示,制备样品是六方和立方两种晶型的混合,沿(002)和(111)晶面择优取向生长。随溅射功率的增大和衬底温度的升高,两种晶型互相竞争生长并分别略微占优势。当溅射功率增大到200 W,衬底温度升高到200℃时,占优势晶型消失,薄膜择优取向特性变得更好。此外,随着溅射气压的增大,样品结晶质量下降,在0.5 Pa时呈现明显非晶化现象。     

衬底温度对低温制备纳米晶硅薄膜的影响

采用传统的射频等离子体增强化学气相沉积技术,在较高的工作气压130Pa和较高的射频功率70W下,在＞100℃的低温下,以0.14nm/s速率制备出优质的纳米晶硅薄膜.研究结果表明,薄膜晶化率和沉积速率与衬底温度有密切关系.当衬底温度＞100℃,薄膜由非晶相向晶相转化,随着衬底温度的进一步升高,薄膜晶化率增大,当温度为300℃时,薄膜的晶化率达82%,暗电导率为10-4·cm-1数量级,激活能为0.31eV.当薄膜晶化后,沉积速率随衬底温度升高而略有增加.     

工艺参数对直流反应磁控溅射ZnO:Al薄膜沉积速率的影响

实验以合金靶材在玻璃衬底上运用直流反应磁控溅射法制备了ZAO(ZnO:Al)透明导电薄膜样品.研究了O2气流量,衬底温度,以及反应气压和溅射功率等工艺参数对ZAO薄膜沉积速率的影响规律.结果表明:沉积速率随O2气流量的增加显著降低,靶面溅射模式由金属模式转变为氧化物模式,而且这种转变趋势在改变其他参数时依然明显;沉积速率随溅射功率的增大几乎成线性增加,但随衬底温度的变化并不大;在反应气压增大的情况下,沉积速率不断上升,达到最大值后,又随气压的增大不断下降.     

ICP-CVD设备低温制备低应力氮化硅薄膜工艺的探索北大核心CSCD

制备低应力的氮化硅薄膜是微机械系统和集成电路中非常重要的工艺。在温度不高于80℃的条件下,采用ICP-CVD设备,利用硅烷和氮气作为前驱体沉积氮化硅介质薄膜。研究了沉积温度、ICP功率、硅烷与氮气流量比例、工作气压等因素对氮化硅薄膜应力的影响,并利用相关的理论合理解释了应力随不同工艺参数变化的原因。根据研究结果,我们优化了氮化硅薄膜沉积的工艺参数,在70℃低温条件下,制备出厚度160 nm,应力0.03 MPa的低应力氮化硅介质薄膜。     

氮化硅介质薄膜内应力的实验研究

研究了等离子体增强化学气相沉积氮化硅介质薄膜的内应力。采用钠光平面干涉测量了氮化硅薄膜内应力,通过改变薄膜沉积时的工艺参数,考察了反应气体流量比、沉积温度、射频功率密度等因素对氮化硅薄膜内应力的影响。在此基础上,对氮化硅介质薄膜本征应力的形成机制进行了分析讨论。     

Optical properties of LPCVD silicon oxynitride

Low pressure chemical vapour deposition (LPCVD) silicon oxynitride films of various compositions (from pure SiO₂ to pure Si₃N₄) were deposited by changing the relative gas flow ratio. The effects of oxygen on the physical properties of the films were studied by spectroellipsometry (using Bruggeman approximation and Wemple Di Domenico model) and infrared spectroscopy. Refractive index measured by spectroellipsometry method is studied as a function of some deposition parameters: temperature of deposition, gases fluxes ratio. The high value of deposition temperature means low values in refractive index. More oxygen into films decreases the refractive index. The refractive index dispersion is studied by single-oscillator Wemple Di Domenico model. The optical band gap varies monotonically from 5 eV for silicon nitride, to 9eV for HTO LPCVD silicon dioxide and for the studied silicon oxynitride was found to be between 5 and 6 eV.     

Experimental study of the effect of process parameters on plasma-enhanced chemical vapour deposition of silicon nitride film

The effect of plasma-enhanced chemical vapour deposition parameters on refractive index and deposition rate of silicon nitride films is investigated. Usually, this kind of study is performed in a laboratory system. In the present work, a horizontal batch system for the simultaneous coating of 100 silicon wafers is used. Using a gas mixture of silane and ammonia as the reactant-gas sources, the effects of the gas flow rate ratio (R = NH3/SiH4 with the total flow rate constant), pressure, power and temperature on the refractive index and deposition rate were studied and the experimental results are presented and discussed.     

Experimental study of the effect of process parameters on plasma-enhanced chemical vapour deposition of silicon nitride film

The effect of plasma-enhanced chemical vapour deposition parameters on refractive index and deposition rate of silicon nitride films is investigated. Usually, this kind of study is performed in a laboratory system. In the present work, a horizontal batch system for the simultaneous coating of 100 silicon wafers is used. Using a gas mixture of silane and ammonia as the reactant-gas sources, the effects of the gas flow rate ratio (R = NH3/SiH4 with the total flow rate constant), pressure, power and temperature on the refractive index and deposition rate were studied and the experimental results are presented and discussed.     

PECVD法低温制备二氧化硅薄膜(英文)

针对金属层间介质以及MEMS等对氧化硅薄膜的需求,介绍了采用等离子增强型化学气相沉积(PECVD)技术,以SiH4和N2O为反应气体,低温制备SiO2薄膜的方法.利用椭偏仪和应力测试系统对制得的SiO2薄膜的厚度、折射率、均匀性以及应力等性能指标进行了测试,探讨了射频功率、反应腔室压力、气体流量比等关键工艺参数对SiO2薄膜性能的影响.结果表明:SiO2薄膜的折射率主要由N2O/SiH4的流量比决定,而薄膜均匀性主要受电极间距以及反应腔室压力的影响.通过优化工艺参数,在低温260℃下制备了折射率为1.45～1.52、均匀性为±0.64%、应力在-350～-16MPa可控的SiO2薄膜.采用该方法制备的SiO2薄膜均匀性好、结构致密、沉积速率快、沉积温度低且应力可控,可广泛应用于集成电路以及MEMS器件中.     

Structural investigation of silicon films chemically vapour deposited onto amorphous SiO2 substrates

The influence of substrate temperature and the silane-to-nitrogen ratio on the structure of silicon films 0.5–0.6 μm thick deposited onto amorphous SiO₂ substrates was investigated by X-ray diffraction. The investigations were carried out for silicon films deposited at various temperatures in the range 500–750 °C and with various silane-to-nitrogen ratios in the range 3.04 × 10^-4-2.84 × 10^-3 by volume. The silicon films deposited at 500 °C were amorphous while the films deposited at 550 °C were randomly oriented polycrystalline. The films deposited in the temperature range 600–700 °C were polycrystalline with a preferred orientation that changed from 〈110〉 through 〈100〉 to 〈111〉. The structure of the films deposited at 750 °C was randomly oriented polycrystalline. Investigations of the influence of the silane-to-nitrogen ratio on the silicon film structure revealed that the structure of films deposited at a substrate temperature of 500 °C was independent of the silane-to-nitrogen ratio. The structure of the films deposited at 600 °C depended on the silane-to-nitrogen ratio and changed from polycrystalline with a 〈110〉 preferred orientation to randomly oriented polycrystalline when the ratio was increased. The structure of films deposited at 700 °C also depended on the silane-to-nitrogen ratio and changed from randomly oriented polycrystalline to polycrystalline with double preferred orientation (〈100〉 and 〈111〉) when the ratio was increased.     

Properties of plasma enhanced chemical vapor deposited silicon nitride for the application in multicrystalline silicon solar cells

Hydrogenated films of silicon nitride (SiNx:H) were investigated by varying the deposition condition in plasma enhanced chemical vapor deposition (PECVD) reactor and annealing condition in infrared (IR) heated belt furnace to find the optimized condition for the application in multicrystalline silicon solar cells. By varying the gas ratio (ammonia to silane), the silicon nitride films of refractive indices 1.85-2.45 were obtained. Despite the poor deposition rate, silicon wafer with the film deposited at 450 °C showed the best minority carrier lifetime. The film deposited with the gases ratio of 0.57 showed the best peak of carrier lifetime at the annealing temperature of 800 °C. The performance parameters of cells fabricated by varying co-firing peak temperature also showed the best values at 800 °C. The multicrystalline silicon (mc-Si) solar cells fabricated in conventional industrial production line applying the optimized film deposition and annealing conditions on large area substrate (125 mm × 125 mm) was found to have the conversion efficiency of 15%.     

Impact of radio frequency source power-induced ion energy on a refractive index of SiN film deposited by a pulsed-PECVD at room temperature

Using a pulsed-plasma enhanced chemical vapor deposition system, silicon nitride films were deposited at room temperature. A refractive index was examined in the range of bias power and duty ratio, 200-800 W and 40-90%, respectively. Ion energy diagnostics was related to the refractive index. The refractive index decreased with decreasing the duty ratio at all powers but 800 W. For all the duty variations at all powers but 200 W, the refractive index was strongly correlated with the ion energy flux. The refractive index varied between 1.662 and 1.817. Using a neural network model, the refractive index was optimized.     

SiOxNy Films deposited with SiCl4 by remote plasma enhanced CVD

Silicon oxynitride films have been deposited with SiCl₄ by remote-plasma enhanced chemical vapor deposition (PECVD) at a substrate temperature of 250°C. Different mixtures of O₂ and NH₃ were used to obtain different oxynitride compositions ranging from SiO₂ to an stoichiometry close to that of silicon nitride. Rutherford backscattering spectrometry was used to determine the chemical composition of the SiO_xN_y films. The behavior of the IR absorption spectra as well as the refractive index measured by ellipsometry were used to estimate the effect of the different deposition parameters. It was found that the IR spectra show a shift of the characteristic peak associated with the stretching vibration mode of the Si-O-Si bonds towards lower wavenumbers as the relative concentration of ammonia was increased with respect oxygen. No double peaks associated with silicon oxide and silicon nitride were observed, indicating the formation of an homogeneous alloy. The IR spectra did not show any presence of water or hydrogen related impurities in the film. Also the effect of a hydrogen flow added during the deposition process on the structural characteristics of the deposited films was studied using dielectric spectroscopy and atomic force microscopy measurements showing that the hydrogen flow added during deposition results in a reduction of the film roughness and a planarization effect, which is very interesting for the application of these films in microelectronics devices.     

Effects of bombardment on optical properties during the deposition of silicon nitride by reactive ion-beam sputtering

Thin silicon nitride (Si(1_x)N(x)) films were synthesized without substrate heating by means of reactive argon-ion sputtering of either silicon or a silicon nitride target in the 1000-1500-eV energy range at a nitrogen partial pressure of 1.3 × 10(-2) Pa and with simultaneous nitrogen ion-assisted bombardment in the 300-500-eV low energy range. The extinction coefficient and refractive index of the films were directly dependent on the N(+) ion-to-atom arrival ratio, assisted ion energy, film growth rate, and indicated a correlation with film stoichiometry and disorder. Si(3)N(4) films were obtained for N(+) ion/Si atom arrival ratios from 0.6 to 1.7 and for different Si:N atom arrival rates and had a refractive index as high as 2.04 (633 nm) and a low hydrogen content as indicated by IR spectra.