Si3N4薄膜的成分与结构研究

通过PECVD方法,在Si基体表面制备了Si3N4薄膜,给出了XRD、TEM、AES、DPS的分析结果,表明Si3N4是非晶态结构,薄膜的主要成分是Si3N4,SEM分析结果显示Si3N4薄膜与基体材料的结合强度高,薄膜致密性好.     

氮化硅薄膜材料的表面结构和热稳定性研究

研究了三种方法制备的氮化硅薄膜的组成、表面结构、热氧化稳定性以及抗离子束损伤等性能。研究发现APCVD法制备氮化硅薄膜的Si3N4含量最高，PRSD法制备的薄膜次之，而PECVD法制备的薄膜Si3N4含量最低。在PRSD薄膜中没有N－H键存在，仅有少量的Si－H键存在，薄膜的热氧化稳定性和抗离子束损伤性能最好。APCVD薄膜中含有少量的N－H和Si－H键，虽然膜层的热稳定性很好，但由于膜层具有较多的缺陷，因此其抗氧化性较差，抗离子束损伤性能也不好。对于PECVD薄膜，由于其形成温度较低，膜层中含有大量的N－H和Si－H键，因此膜层的热稳定性和抗离子束损伤性能最差。此外，还发现XPS获得的N／Si原子比和膜层的真实成分校一致，而RBS和AES由于离子束损伤效应，其结果偏低。氮化硅薄膜热稳定性差和离子束损伤的本质均因氯化硅的脱氮分解。热氧化的本质是膜层中自由硅和气氛中残余氧的氧化反应。     

电弧离子镀TiSiN薄膜的结构及摩擦性能

为实现电弧离子镀TiSiN薄膜成分可控,通过改变靶的相对电流在304不锈钢表面沉积TiSiN薄膜,采用厚度仪、能谱仪、扫描电镜、X射线衍射仪及摩擦试验研究了其形貌、结构及摩擦性能。结果表明:TiSiN薄膜中Si以非晶态Si3N4形式存在,抑制了面心立方结构的Ti N晶粒生长,形成纳米晶Ti N/非晶Si3N4(nc-Ti N/α-Si3N4)纳米复合结构;与Ti N薄膜相比,TiSiN薄膜具有更平整的表面,Si含量为4.08%(原子分数)时薄膜表面最光滑平整;Ti N薄膜的硬度为2 312 HK左右,掺杂Si元素后,由于细晶强化作用,薄膜的硬度显著提高,Si含量为2.76%(原子分数)时达到最大值,约为3 315 HK;进一步增加Si含量,TiSiN薄膜硬度略有下降;TiSiN薄膜的摩擦系数明显低于Ti N薄膜,且随着Si含量增加,摩擦系数逐渐变小,在Si含量为2.76%和4.08%(原子分数)时低至0.4左右。     

蓝宝石和硅衬底上氮化硅薄膜的制备和性能研究

采用射频磁控反应溅射法,以高纯Si为靶材,高纯N2气为反应气体,在蓝宝石和硅衬底上制备了氮化硅薄膜.并对Si3N4薄膜的沉积速率、成分、结构及红外光学性能等进行了研究.实验结果表明,沉积薄膜中Si和N的比接近3∶4,形成了Si3N4化合物,呈非晶态结构.制备的Si3N4薄膜的硬度明显高于蓝宝石衬底的硬度,且与蓝宝石衬底结合牢固,可提供良好的保护性能.     

射频PECVD法制备Si-C-H薄膜的研究

本实验采用射频PECVD方法以高氢稀释的SiH4和CH4混合气体,在300℃低温下生长出了Si-C-H薄膜,并对沉积的薄膜在N2氛围中进行了退火研究.用红外吸收光谱、X射线衍射、原子力显微镜对薄膜进行热处理前后的结构和表面形貌分析.测试结果显示在所沉积的薄膜中含有Si-C键,分布于结晶性好的Si晶粒之间.     

Si-N-O薄膜结构对薄膜血液相容性的影响

采用非平衡磁控溅射(UBMS450)法在(100)单晶硅表面制备Si-N-O薄膜.利用X射线光电子能谱(XPS)表征薄膜的成分结构;用血小板粘附试验表征薄膜结构对薄膜血液相容性的影响.研究结果表明,以无机Si为主的Si-N-O薄膜,其血液相容性较差;键合少量O的Si3N4薄膜,其血液相容性较佳.Si-N-O薄膜中N含量和O含量的变化,是导致薄膜结构变化的重要因素.     

氧化钒薄膜的厚度对薄膜电学特性的影响

利用直流反应磁控溅射法在表面覆盖有Si3N4薄膜的Si(100)基片上制备了不同厚度的氧化钒薄膜.用光谱式椭偏仪对薄膜的厚度进行了测试.采用四探针测试系统对制备的薄膜进行了方阻和方阻温度系数的分析,发现薄膜的厚度对薄膜的电学特性有很大的影响.实验结果表明氧化钒薄膜的厚度调整可作为调控氧化钒薄膜性能的一种重要工艺手段.     

Si和C的存在形态对TiSiCN薄膜微观结构与性能的影响

为扩展Ti Al N和Ti CN薄膜的应用,以适应高速切削和绿色干式切削加工技术发展趋势和要求,采用工业化多弧离子镀在工业用钢H13表面制备Ti SiCN硬质薄膜,以改善H13钢的力学和摩擦学性能。借助扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪、维氏显微硬度计、摩擦磨损仪研究了Si和C的存在形态及其对Ti SiCN薄膜的微观形貌、微观结构、硬度和摩擦磨损性能的影响。结果表明:Ti Si CN薄膜组织致密,具有纳米晶Ti(CN)与非晶相(SiC、Si3N4和C);薄膜中C原子固溶于Ti(CN)中,随着C含量的增加,Ti(CN)固溶度增加;部分C以非晶态的形式存在,起到阻碍Ti Si CN纳米晶粒生长作用; Si以非晶SiC和Si3N4相的形式存在,并包裹Ti CN纳米晶,抑制薄膜晶粒的长大;高Si含量Ti Si CN-No.2薄膜和高C含量Ti Si CN-No.3薄膜表现出高硬度和耐磨减摩特性。     

ECR-PECVD制备氮化硅薄膜的键态结构

用红外光谱和拉曼光谱分析了用低温电子回旋共振等离子体CVD技术制备的Si3N4薄膜的键态结构。结果表明Si3N4薄膜主要由Si-N键结构组成，还含有Si-H和Si-O-Si键结构。随着沉积温度的提高，Si3N4薄膜中的Si-H键减少，氢含量降低。可利用提高沉积温度来减少Si3N4薄膜中的氢含量。在沉积温度为420℃时Si3N4薄膜的Raman光谱在短波方向出现一新的展宽的拉曼散射峰。     

聚苯胺薄膜的制备及其C—V特性研究

报导了采用PECVD技术制备聚苯胺薄膜及沉积条件对薄膜沉积速率的影响,红外吸收光谱和电容－电压法表征了薄膜的组成及介电特性。     

气体流量比对反应溅射Si3N4薄膜的影响

利用射频磁控反应溅射法，以高纯Si为靶材，高纯N2气为反应气体，在Si衬底上制备出了Si3N4薄膜，研究了气体流量比对薄膜质量的影响。结果表明，薄膜的沉积速率主要与气体的流量比有关，随着气体流量比的增加，沉积速率下降，靶面的溅射由金属模式过渡到氮化物模式；薄膜中N／Si的原子比增加；红外吸收谱的Si—N键的振动峰向标准峰逼近。     

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。     

氮化碳薄膜的结构与特性

采用射频等离子体增强化学气相沉积（ＣＶＤ）＋负偏压热丝辅助方法直接在Ｓｉ（１００）衬底上制备了多晶Ｃ_３Ｎ_４薄膜．Ｘ射线衍射测试表明,薄膜同时含有α－和β-Ｃ_３Ｎ_４晶相以及未知结构,没有观测到石墨衍射峰．利用扫描电子显微镜观测到线度约２μｍ、横截面为六边形的β－Ｃ_３Ｎ_４晶粒．纳米压痕法测得薄膜的硬度达７２．６６ ＧＰａ．     

LPCVD氮化硅薄膜的化学组成

分别采用X光电子能谱(XPS)、俄歇电子能谱(AES)、傅立叶红外光谱(FTIR)以及弹性反冲探测(ERD)等方法,分析了三氯硅烷-氨气-氮气体系低压化学气相沉积(LPCVD)氮化硅(SiNx)薄膜的化学组成,并利用原子力显微镜(AFM)观察了SiNx薄膜的表面形貌.XPS分析结果表明,当原料气中氨气与三氯硅烷的流量之比小于3时获得富Si的SiNx薄膜,当流量之比大于4时获得近化学计量的SiNx薄膜(x=1.33).AES深度分析与XPS分析结果很好地吻合,在835cm-1产生的强红外吸收峰表明Si-N键的形成,ERD分析表明所制备SiNx薄膜中的氢含量很低(1.2at.%).AFM分析结果表明,所沉积的SiNx薄膜均匀、平整,薄膜的均方根粗糙度RMS仅为0.47nm.     

Improved growth of GaN layers on ultra thin silicon nitride/Si (1 1 1) by RF-MBE

High-quality GaN epilayers were grown on Si (1 1 1) substrates by molecular beam epitaxy using a new growth process sequence which involved a substrate nitridation at low temperatures, annealing at high temperatures, followed by nitridation at high temperatures, deposition of a low-temperature buffer layer, and a high-temperature overgrowth. The material quality of the GaN films was also investigated as a function of nitridation time and temperature. Crystallinity and surface roughness of GaN was found to improve when the Si substrate was treated under the new growth process sequence. Micro-Raman and photoluminescence (PL) measurement results indicate that the GaN film grown by the new process sequence has less tensile stress and optically good. The surface and interface structures of an ultra thin silicon nitride film grown on the Si surface are investigated by core-level photoelectron spectroscopy and it clearly indicates that the quality of silicon nitride notably affects the properties of GaN growth.     

水溶性胶态成型工艺制备氮化硅耐磨结构陶瓷

以氮化硅粉末为原料, 采用水溶性胶态成型工艺制备高耐磨氮化硅陶瓷. 采用正交设计的方法来优化制备高品质注浆料, 并研究了掺杂分散剂后Zeta电位的变化. 同时, 还对氮化硅陶瓷烧结体的显微结构、力学性能和耐磨性能进行了研究. 结果表明: 当氮化硅浆料中固相体积分数为45%时, 可制得体积密度较高的精细氮化硅陶瓷材料, 断裂韧性可达7.21MPa·m^1/2, 硬度为9.30GPa. 通过抗耐磨损实验研究表明: 干摩擦条件下, 氮化硅陶瓷发生了晶粒脆性断裂和脱落; 水润滑条件下, 摩擦表面产生了氢氧化硅 反应膜, 降低了磨损, 主要是化学腐蚀磨损.     

Highly Porous Silicon Membranes Fabricated from Silicon Nitride/Silicon Stacks

Nanopore formation in silicon films has previously been demonstrated using rapid thermal crystallization of ultrathin (15 nm) amorphous Si films sandwiched between nm‐thick SiO₂ layers. In this work, the silicon dioxide barrier layers are replaced with silicon nitride, resulting in nanoporous silicon films with unprecedented pore density and novel morphology. Four different thin film stack systems including silicon nitride/silicon/silicon nitride (NSN), silicon dioxide/silicon/silicon nitride (OSN), silicon nitride/silicon/silicon dioxide (NSO), and silicon dioxide/silicon/silicon dioxide (OSO) are tested under different annealing temperatures. Generally the pore size, pore density, and porosity positively correlate with the annealing temperature for all four systems. The NSN system yields substantially higher porosity and pore density than the OSO system, with the OSN and NSO stack characteristics fallings between these extremes. The higher porosity of the Si membrane in the NSN stack is primarily due to the pore formation enhancement in the Si film. It is hypothesized that this could result from the interfacial energy difference between the silicon/silicon nitride and silicon/silicon dioxide, which influences the Si crystallization process.     

Bulk and interface properties of low-temperature silicon nitride films deposited by remote plasma enhanced chemical vapor deposition

Hydrogenated silicon nitride (a-SiN_x:H) films were deposited at temperatures ranging from 50 to 300 °C with remote plasma enhanced chemical vapor deposition (RPECVD) from NH}_{3 and SiH}_{4. The effect of the operating variables, such as deposition temperature and especially the partial pressure ratio of reactant (R=NH₃/SiH₄) on the properties of the Sa-SiN_x:H interface was investigated. The H^* radical was dominantly observed and the deposition rate was proportional to the NH^* radical concentration. The density of highly energetic N ₂ ^* radicals increased in the high plasma power regime in which the film surface was roughened, but they promote surface reactions even at low temperature. The refractive index was more closely related to the film stoichiometry than film density. The interface trap density is related to the amount of silicon intermediate species and Si–NH bonds at the Si/SiN_x:H interface and it can be minimized by reducing the intermediate Si species and Si–NH bonding state. The films showed a midgap interface trap density of 2 × 10¹¹ - 2 × 10¹²cm^-2. © 2001 Kluwer Academic Publishers     

磁控溅射制备TiN薄膜影响因素的研究

采用磁控溅射法在硅基片表面沉积TiN薄膜,研究了溅射气压、氮气流量、氩气流量、溅射电流等溅射参数对TiN薄膜导电性能的影响.实验参数采用正交设计法选取,经模糊分析得出,所考察的因素对薄膜光催化性能的影响次序由大到小依次为溅射电流、气体流量、溅射气压.进一步研究影响最大的溅射电流对薄膜结构与电学性能的影响,结果发现:溅射电流的增大使溅射粒子的动能随之增大,薄膜生长加快;薄膜的电阻率存在最小值.     

Optical and structural features of silicon-rich hydrogenated amorphous silicon nitride thin films

A systematic study of fabrication and effect of post-deposition processing on the optical and structural features of silicon-rich hydrogenated amorphous silicon nitride thin films deposited by Hg-sensitized Photo-Chemical Vapour Deposition technique is presented. Both deposition parameters and post-deposition thermal treatment resulted into substantial change in the refractive index associated with the densification of the film. Our studies reveal that the presence of hydrogen and its out-diffusion upon thermal treatment play a crucial role in the overall structural evolution, specially the stabilization of individual phases such as Si and Si3N4. We further report the room-temperature photoluminescence from as-deposited films, which is due to formation of silicon nanostructures in crystalline and amorphous forms. These studies are of great interest from the prospective of commercially viable Si-based technology.