气体压强对非晶InGaAs薄膜光学常数的影响

论述一种用透射谱包络线法计算非晶薄膜的折射率、消光系数和光学带隙的方法。通过正交实验确定除压强之外的工艺参数,研究压强的改变对薄膜主要光学常数的影响,运用最小二乘法、内插值法在matlab编程基础上,拟合出光学常数曲线,借由观察曲线的特点,分析在低工作气压下,气压的改变对光学常数的影响。     

离子束辅助沉积非晶硅薄膜红外光学特性研究

为了得到非晶硅（a-Si）薄膜红外光学常数与工艺参数之间的关系,采用Ar离子束辅助电子束热蒸发技术制备a-Si薄膜,并利用椭偏仪和分光光度计测量了薄膜的光学常数,分析了薄膜沉积速率、基底温度和工作真空度对a-Si薄膜折射率和消光系数的影响.实验结果表明：影响a-Si薄膜光学常数的主要工艺因素是沉积速率和基底温度,工作真空度的影响最小.当沉积速率和基底温度升高时,薄膜的折射率先增大后减小;当工作真空度升高时,薄膜的折射率增大.在波长1~5μm之间,a-Si薄膜的折射率变化范围为2.47~3.28.     

甲烷流量对类金刚石薄膜氢含量和性能的影响

采用射频等离子体增强化学气相沉积(RF-PECVD)法,固定甲烷气压为1.33Pa,变化甲烷流量30～100sccm在玻璃上制备了一系列类金刚石(DLC)薄膜,采用残余气体分析仪、拉曼光谱和椭偏仪测试手段分别研究了甲烷等离子体中氢分压的变化、DLC膜中的氢含量和DLC膜的光学性能,采用摩擦磨损仪研究了DLC膜的耐摩擦性能。结果表明,随甲烷流量的增大,甲烷等离子体中的氢分压和DLC膜中的氢含量减小,光学带隙从1.77eV减小到1.65eV。在300～2 500nm的波长范围内折射率随流量的增大而增大,中心波长550nm的折射率从2.11增加到2.15。普通玻璃的摩擦系数约为1.2,而镀有DLC膜的玻璃的摩擦系数下降到0.4,甲烷流量为60sccm时制备的DLC膜耐磨性最佳。     

无定形a—Si：F：H的特点及其微观分析

本文叙述用辉光放电分解SiF_2和H_2的混合物形成无定形a-Si:F:H薄膜。这种薄膜具有高电导率,高载流子寿命,高热稳定性以及低杂质扩散等优点,并试从结构上加以初步分析。     

非晶硅薄膜PECVD法制备与光学性质表征

在普通玻璃上采用等离子体增强化学气相沉积(PECVD)方法制备氢化非晶硅薄膜,研究了在不同温度、压力、功率、H2/SiH4气体流量比等条件下氢化非晶硅的沉积速率,折射率、消光系数、吸收系数、光学禁带宽度等光学性质。实验结果表明非晶硅薄膜的折射率随着入射光波长的增加而减小;在500 nm处吸收系数高达8.5×104cm-1,光学禁带宽度在1.60—1.78 eV之间变化。     

磁控溅射法镀制氮化铝薄膜特性研究

氮化铝薄膜具有高折射率,良好的化学稳定性,耐磨摩、高电阻等特性在微电子器件和光学薄膜中有着广泛地应用.本文研究了反应式磁控溅射方法利用Ar/N2混合气体镀制氮化铝薄膜的工艺过程,实验表明在高真空和高泵浦速率条件下,放电电压直接依赖于反应气体珠浓度.薄膜的折射率,消光系数和薄膜硬度都依赖于氮气浓度的比例.通过工艺研究,找到了氮气在不同浓度下对氮化铝薄膜的折射率,消光系数以及薄膜硬度的影响,找出了镀制氮化镀制氮化铝薄膜的最佳工艺参数.在Ar/N2工作气体中氮气含量保持在40%条件下,用反应式磁控溅射方法,可以精确镀制出良好的氮化铝薄膜,其中折射率范围在2.25~2.4之间,消光系数为10-3,薄膜显微硬度大于20GPa.该薄膜可以广泛应用于微电子器件和光电器件上.     

生长温度对掺钛氧化锌薄膜光学性质的影响

以氧化锌钛陶瓷靶作为溅射源,采用磁控溅射技术在玻璃衬底上制备了掺钛氧化锌(TZO)透明导电薄膜,通过X射线衍射仪和分光光度计测试表征以及全光谱拟合法分析,研究了生长温度对TZO薄膜晶体结构和光学性质的影响.结果表明:所有TZO样品均为六角纤锌矿结构,并具有(002)择优取向,生长温度对薄膜晶粒尺寸和光学透射率的影响较明显,而对折射率、消光系数和光学能隙的影响较小.当生长温度为200℃时,TZO薄膜的晶粒尺寸最大,可见光范围平均透射率(含衬底)为76.1%,对应的直接光学能隙为3.45 eV.     

a-Si/μc-Si叠层电池中间层材料SiO_x:H制备研究

为提高a-Si/μc-Si叠层太阳电池的效率,采用射频等离子体增强化学气相沉积(RF-PECVD)技术,制备了系列n型掺磷硅氧(SiOx:H)薄膜作为中间层,研究了CO2/Si H4气体流量比、沉积功率和PH3掺杂浓度等工艺参数对材料光电特性的影响,获得了折射率、电导率和禁带宽度能够在较大范围内调控的SiOx:H薄膜。     

氧分压对TiO2薄膜光学性能的影响

为得到光学性能良好、稳定的TiO2薄膜,采用离子束溅射的方法,改变氧分压,在k9玻璃上制备出不同结晶取向不同光学常数的TiO2薄膜.采用椭圆偏振光谱仪测试、拟合得到薄膜的厚度、折射率和消光系数.薄膜通过400℃退火,利用X射线衍射仪(XRD)对薄膜的成分、结晶和取向进行分析.实验结果发现,随氧分压增加折射率减低,当氧分压达到1.0×10-2Pa时,折射率在2.43附近,变化趋于稳定.氧分压对薄膜的消光系数k影响较大,氧分压高于1.0×10-2Pa时在可见光和近红外区薄膜消光系数近似为0.随氧分压降低,薄膜从(101)向(200)转变.在此氧分压下,得到的薄膜折射率稳定,消光系数相对较小.     

非晶硅(a-Si)复合钝化层对改善低频噪声的作用

本文研究了由辉光放电(GD)方法制备的氢化非晶硅(a-Si:H)钝化膜对于降低集成电路低频噪声的作用。提出了一种较佳化的a-Si:H/SiN复合钝化层结构。实验表明,当频率f<10~3Hz时,采用复合钝化层的电路其等效输入噪声电压减少约一个数量级。同时对该复合钝化膜进行了可靠性试验。     

Raman and ellipsometric characterization of hydrogenated amorphous silicon thin films

Hydrogenated amorphous silicon (a-Si:H) thin films were deposited by plasma-enhanced vapor deposition (PECVD) at different silane temperatures (Tg) before glow-discharge. The effect of Tg on the amorphous network and optoelectronic properties of the films has been investigated by Raman scattering spectra, ellipsometric transmittance spectra, and dark conductivity measurement, respectively. The results show that the increase in Tg leads to an improved ordering of amorphous network on the short and intermediate scales and an increase of both refractive index and absorption coefficient in a-Si:H thin films. It is indicated that the dark conductivity increases by two orders of magnitude when Tg is raised from room temperature (RT) to 433 K. The continuous ordering of amorphous network of a-Si:H thin films deposited at a higher Tg is the main cause for the increase of dark conductivity.     

PECVD工艺参数对SiO_2薄膜光学性能的影响

为探索利用等离子体增强化学气相沉积(Plasma Enhanced Chemical Vapor Depo-sition,PECVD)技术制作光学薄膜的有效方法.以SiH4和N2O作为反应气体,通过采用M-2000UI型宽光谱变角度椭圆偏振仪对制作样片进行测试,分析了薄膜沉积过程中的不同的工艺参数对SiO2薄膜光学性能的影响.实验结果表明:在PECVD技术工作参数范围内,基底温度为350℃,射频功率为150 W,反应气压为100 Pa时,能够沉积消光系数小于10-5,沉积速率为(15±1)nm/min,折射率为(1.465±0.5)×10-4的SiO2薄膜.     

Preparation and Properties of a-Si：H Thin Films Deposited on Different Substrates

The effects of different substrates on the structure and hydrogen evolution from a-Si： H thin films deposited by plasma enhanced chemical vapour deposition were studied, as well as the similar films exposed to an hydrogen plasma. Spectroscopic ellipsometry and hydrogen evolution measurements were used to analyse the effects of the substrate and hydrogen plasma on the films microstructure, thickness, hydrogen content, hydrogen bonding and hydrogen evolution. The hydrogen evolution spectra show a strong substrate dependence. In particular on crystalline silicon substrate, the formation of bubbles was observed. For different substrates, hydrogen plasma treatments lightly affected the hydrogen evolution spectra. These results indicate that the action of hydrogen in a-Si：H was modified by the nature of the substrate.     

Depth profile study on Raman spectra of high-energy-electron-irradiated hydrogenated amorphous silicon films

According to the different penetration depths for the incident lights of 472 nm and 532 nm in hydrogenated amorphous silicon (a-Si:H) thin films, the depth profile study on Raman spectra of a-Si:H films was carried out. The network ordering evolution in the near surface and interior region of the unirradiated and irradiated a-Si:H films was investigated. The results show that there is a structural improvement in the short- and intermediate-range order towards the surface of the unirradiated a-Si:H films. The amorphous silicon network in the near and interior region becomes more disordered on the short- and intermediate-range scales after being irradiated with high energy electrons. However, the surface of the irradiated films becomes more disordered in comparison with their interior region, indicating that the created defects caused by electron irradiation are concentrated in the near surface of the irradiated films. Annealing eliminates the irradiation effects on a-Si:H thin films and the structural order of the irradiated films is similar to that of the unirradiated ones after being annealed. There exists a structural improvement in the short- and intermediate-range order towards the surface of the irradiated a-Si:H films after being annealed. Supported by the National Outstanding Young Scientists Foundation of China (Grant No. 60425101) and the Science Foundation of General Armament Department of China (Grant No. 06DZ02)     

Correlations between the Optical Properties and the Microstructure of TiO2 Thin Films Prepared by Reactive Electron-beam Evaporation

High refractive index TiO₂ thin films were deposited on BK7 glass by reactive electron—beam (REB) evaporation at pressure of 2×10⁻² Pa, deposition rate of 0.2 nm/s and at various substrate temperatures from 120°C to 300°C. The refractive index and the thickness of the films were measured by visible spectroscopic ellipsometry (SE) and determined from transmission spectra. Optical properties and structure features were characterized by UV-VIS, SEM and XRD, respectively. The measurement and analysis on transmission spectra of all samples show that with the substrate temperature increasing from 120°C to 300°C, the refractive indices of thin films increase from 1.7 to 2.1 and the films after heat treatment have higher refractive indices due to its crystallizing. The XRD analysis results indicate that the structure of TiO₂ thin films deposited on BK7 glass at substrate temperatures of 120°C, 200°C and 300°C is amorphous, after post-annealing under air condition at 400°C for 1 hour, the amorphous structure is crystallized, the crystal phase is of 100% anatase with strong preferred orientation (004) and the grain size of crystalline is within 3.6–8.1 nm, which is consistent with results from SEM observation. WANG Xue-hua: Born in 1976. Funded by the Youth Project Foundation of Hubei Provincial Education Department (No. 2003B00)     

Ar/CH_4流量比对a-C∶H薄膜沉积速率及性能的影响

为研究气体流量比对非平衡磁控溅射沉积含氢类金刚石薄膜（Diamond-Like Carbon,DLC）沉积速率及性能的影响,在不同Ar/CH4流量比条件下将a-C∶H沉积在单晶硅基底,采用傅里叶红外光谱、椭偏仪、表面轮廓仪对薄膜的沉积速率、光学特性及表面粗糙度进行研究.实验结果表明：引入甲烷气体后,非平衡磁控溅射沉积a-C∶H薄膜沉积速率大幅度提高;在3～5μm波段硅基底上镀制a-C∶H膜具有良好的红外增透特性,薄膜峰值透射率明显受到Ar/CH4流量比的影响,Ar/CH4流量比1∶3时,制备的a-C∶H峰值透过率可达69.24%;a-C∶H薄膜的折射率和消光系数随着CH4流量的增加而增大;a-C薄膜的粗糙度要优于a-C∶H薄膜,a-C∶H薄膜的粗糙度随厚度的增加而变大.