Impacts of hydrogen dilution on growth and optical properties of a-SiC:H films

Hydrogenatedamorphoussiliconcarbon(a-SiC:H)filmshavefoundagreatdealofusesinsolarcells[1],thinfilmtransistors[2],lightemittingdiodes[3],ultravioletimagesensors[4],microfluidiccoatings[5]andprotectivebarrierforcorrosionorthermaloxidation[6,7],becauseofitsuniquepropertiessuchaswideopticalbandgap,highmechanicalhardnessandchemicalstability.However,astheCcontentincreases,theelectronicandstructuralpropertiesofthefilmstendtobeinferior[8].Althoughinrecentyearsmuchworkhasbeendevotedtoexploringthedeposi…     

液相沉积法制备掺银TiO2薄膜及光催化性能

为了提高TiO2薄膜光催化剂的活性,通过在氟钛酸铵、硼酸混合溶液中加入硝酸银,应用液相沉积法(LPD)制备了掺银TiO2薄膜.采用XRD、SEM、XPS、UV-vis等手段对其组成、表面形貌和结构进行了测试表征;并以甲基橙为模型物,进行降解实验评价Ag-TiO2薄膜的光催化性能.实验结果表明:硼酸/氟钛酸铵摩尔比为2～4,热处理温度为400℃,硝酸银掺杂量为0.03 mol/L时,Ag-TiO2薄膜具有良好的锐钛矿相晶型,同时具有较高的光催化性能.     

气体压强对n型a-Si:H薄膜光学性能的影响

用射频等离子增强化学气相沉积(RF-PECVD)制备磷掺杂氢化非晶硅(a-Si:H)薄膜,研究了辉光放电气体压强(20~80 Pa)对薄膜折射率、消光系数、光学带隙以及氢含量的影响;用激光拉曼光谱研究了气体压强对a-Si:H薄膜微结构的影响,并与薄膜的光学性能进行了综合讨论。结果表明,随着辉光放电气体压强的增加,a-Si:H薄膜的光学带隙和氢含量都有不同程度的增大,但折射率和消光系数却逐步减小;与此同时,薄膜内非晶网络的短程和中程有序程度逐渐恶化。     

Al-induced Lateral Crystallization of Amorphous Si Thin Films by Microwave Annealing

Al-induced lateral crystallization of amorphous silicon thin films by micr owave annealing is investigated,The erystallized Si films are examined by optical microscopy,Raman spectroscopy ,transimission electron microscopy and transmission electron diffraction micrography.After microwave annealing at 480 ℃ for 50min the amorphous Si is completely cystallized with lagrge grains of main (111) orientation,The rate of lateral crystallization is 0.04μm/min,This process,labeled MILC-MA ,not only lowers the temperature but also reduces the time of crystallization.The crystallization.mechanism during microwave annealing and the electrical properies of polycrystalline Si thin films are analyzed.This MILC-MA process has potentila application in large area electronics.     

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.     

High rate deposition of microcrystalline silicon films by high-pressure radio frequency plasma enhanced chemical vapor deposition (PECVD)

Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by high-pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate and crystallinity varying with the deposition pressure, rf power, hydrogen dilution ratio and electrodes distance were systematically studied. By optimizing the deposition parameters the device quality μc-Si:H films have been achieved with a high deposition rate of 7.8 ?/s at a high pressure. The V _oc of 560 mV and the FF of 0.70 have been achieved for a single-junction μc-Si:H p-i-n solar cell at a deposition rate of 7.8 ?/s. Supported by the National Natural Science Foundation of China (Grant No. 50662003) and the State Development Program for Basic Research of China (Grant No. G2000028208)     

Structure and Composition of Crystalline Carbon Nitride Films Synthesized by Microwave Plasma Chemical Vapor Deposition

Crystalline carbon nitride thin films were prepared on Si (100) substrates by a microwave plasma chemical vapor deposition method, using CH4/N2 as precursor gases. The surface morphologies of the carbon nitride films deposited on Si substrate at 830℃ are consisted of hexagonal crystalline rods. The effect of substrate temperature on the formation of carbon nitrides was investigated. X-ray photoelectron spectroscopy analysis indicated that the maximum value of N/C in atomic ratio in the films deposited at a substrate temperature of 830℃ is 1 .20, which is close to the stoichiometric value of C3N4. The X-ray diffraction pattern of the films deposited at 830℃ indicates no amorphous phase in the films, which are composed of β- and α-C3N4 phase containing an unidentified C-N phase. Fourier transform infrared spectroscopy supports the existence of C-N covalent bond.     

Structure and Composition of Crystalline Carbon Nitride Films Synthesized by Microwave Plasma Chemical Vapor Deposition

Crystalline carbon nitride thin films were prepared on Si (100) substrates by a microwave plasma chemical vapor deposition method, using CH4/N2 as precursor gases. The surface morphologies of the carbon nitride films deposited on Si substrate at 830℃ are consisted of hexagonal crystalline rods. The effect of substrate temperature on the formation of carbon nitrides was investigated. X-ray photoelectron spectroscopy analysis indicated that the maximum value of N/C in atomic ratio in the films deposited at a substrate temperature of 830℃ is 1.20, which is close to the stoichiometric value of C3N4. The X-ray diffraction pattern of the films deposited at 830℃ indicates no amorphous phase in the films, which are composed of - and -C3N4 phase containing an unidentified C-N phase. Fourier transform infrared spectroscopy supports the existence of C-N covalent bond.     

Performance improvement of n-i-p μc-Si:H solar cells by gradient hydrogen dilution technique

High pressure radio frequency plasma enhanced chemical vapor deposition(RF-PECVD)process was adopted to investigate the effect of constant hydrogen dilution technique and gradient hydrogen dilu-tion technique on the structural evolution of intrinsic films and the performance of n-i-p microcrystal-line silicon solar cells.The experiment results demonstrated that the grain size and crystalline volume fraction along the growth direction of intrinsic films can be controlled and the performance of solar cells ca...     

等离子体化学气相沉积硅外延

运用射频等离子体化学气相沉积在Ｓｉ（１００）Ｐ进行外延试验，并用四极质谱仪（ＱＭＳ）进行监测，得出了ＳｉＨ４浓度的变化规律。试验结果表明在６００℃，压力为３００ｍＴｏｒｒ时，外延生长率最高，为４５０／ｍｉｎ，膜中Ｈ含量也较低，为１．５％［ａｔ］。在压力为３０ｍＴｏｒｒ，７００℃时，外延生长率为５９．６／ｍｉｎ，膜中Ｈ含量降至２．７５％［ａｔ］。     

离子束增强沉积Al-N共掺杂ZnO薄膜的制备

用Al2O3粉体与ZnO粉体均匀混合,压制成溅射靶。在Si和SiO2/Si衬底上,用离子束增强沉积(IBED)方法对沉积 膜作Ar+/N+注入,制备Al-N共掺杂氧化锌薄膜(ANZO)。在氮气氛中作适当的退火,可以方便地获得取向单一、结构致 密、性能良好的共掺杂ZnO薄膜。探索用IBED方法在Si和SiO2衬底上制备优质掺杂薄膜的可能性。初步研究了ANZO共掺 杂薄膜的结构、电学和光学性能。     

立方氮化硼(c-BN)薄膜的光学带隙

用两步射频溅射法在n型Si(111)片和熔融石英片上沉积出不同体积分数的立方氮化硼(c-BN)薄膜,薄膜的成分由傅里叶红外吸收谱标识;用紫外-可见分光光度计测量了沉积在石英片上的BN薄膜的透射光谱T_e(λ)和反射光谱R_e(λ),薄膜的厚度用台阶仪测得。由透射、反射光谱计算了薄膜的光吸收系数a,进而采用有效的中间形式,确定了氮化硼薄膜的光学带隙。结果表明:随着c-BN体积分数的增加,光学带隙随之增大。确定出的光学带隙和经验公式的计算结果相吻合。     

MPECVD法在抛光石英玻璃上沉积金刚石薄膜

采用微波等离子体增强化学气相沉积方法(MPECVD),利用氢气和甲烷混合气体,在抛光石英基片上低温沉积出金刚石薄膜。用扫描电子显微镜(SEM)、激光拉曼光谱仪(Raman)和傅立叶红外光谱仪(FTIR)对薄膜的表面形貌、颗粒尺寸、纯度和光学透过性能进行了表征。通过SEM发现,得到的金刚石薄膜的颗粒尺寸为0.2~0.3μm,形核密度超过109cm-2,从薄膜形貌可以发现,较高温度有利于提高薄膜的生长速率和颗粒尺寸的均匀性。通过拉曼光谱和红外透射光谱分析发现,较高温度下沉积的薄膜具有较高的金刚石相含量,薄膜的光学透过性能也相对较好。     

Gold Nanoparticulate Thin Films Fabricated by the Electrostatic Self—Assembly Process

Gold colloids were prepared by citrate-induced reduction of hydrogen tetrachlorourate, and gold nanoparticles were electrostatically self-assembled with poly (diallyldimethylammonium chloride) into multilayer thin films on silicon and quartz substrates. The particulate thin films were characterized by UV-vis spectroscopy, surface enhanced Raman scattering, atomic force microscopy and resistivity measurements. Due to the interparticle coupling between individual gold particles, an obvious collective particle plasmon resonance was observed on UV-vis spectra, and the particulate thin films exhibited a strong SERS effect. For multilayer thin films with a high particle coverage on substrates, resistivity of the order of 10⁻⁴Ω·cm was yielded. Yu Hai-hu This research was financially supported by China Scholarship Council and the Natural Science Foundation of Hubei Province (Project 2000J002)     

半导体器件钝化层Si3N4薄膜的制备及特性研究

采用热分解法在硅衬底上制备了Si3N4薄膜，根据在制备过程中薄膜生长速度随颜色的变化，研究了衬底温度和薄膜沉积速率之间的关系，分别利用AFM对薄膜表面进行观测，C—V法对薄膜和硅片界面态进行了测试。结果表明：所制备的Si3N4薄膜在硅片上以无定形方式存在，在Si3N4薄膜和硅界面之间存在着大量的表面电荷，由于这种高密度表面电荷的存在，导致Si3N4薄膜不适于直接作为半导体器件的表面钝化层。     

微波电子回旋共振等离子体溅射法沉积ZnO薄膜

ＺｎＯ薄膜具有强的压电和光电效应，广泛用于制作各种声电和声光器件中．本文报道了用微波ＥＣＲ等离子体溅射法沉积了ＺｎＯ薄膜，并研究了该法制备ＺｎＯ膜的工艺．结果表明，所形成的ＺｎＯ膜的性质强烈地依赖于溅射沉积条件．     

激发频率对纳米晶硅薄膜微结构的影响

以SiH4和H2为气源,采用等离子体增强化学气相沉积(PECVD)技术制备了纳米晶硅薄膜,利用傅里叶变换红外光谱技术对不同激发频率下薄膜的微结构变化进行了研究.结果表明,薄膜中的氢含量(摩尔分数)和硅氢键合模式与激发频率有密切关系,提高激发频率可降低薄膜中的氢含量,并且硅氢键合以SiH2为主.     

Structural and physical properties of permalloy thin films prepared by DC magnetron sputtering at different substrate temperature

Permalloy Ni80Fe20 films have been grown on thermal oxidized Si (111) wafers by magnetron sputtering at well-controlled substrate temperatures of 300, 500, 640 and 780 K in 0.65 Pa argon pressure. The base pressure was about 1×10-4 Pa. The deposition rate was about 5 nm/min for all the films. The structure of the films was studied using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the films was analyzed using scanning Auger microprobe. The resistance and magnetoresistance of the films were measured using four-point probe technique. The results show that the content of oxygen in the films decreases gradually with raising substrate temperature. In addition, the surface morphology of the films presents notable change with the increasing of the substrate temperature; the residual gases and defects decrease and the grains have coalesced evidently, and then the grains have grown up obviously and the texture of (111) orientation develops gradually in the grow     

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.     

铝掺杂氧化锌薄膜的电学及光学性能

利用脉冲激光沉积法,在氧气氛下(氧分压为11 Pa)以石英玻璃为基体沉积了铝掺杂氧化锌薄膜。靶材选用锌铝合金靶,沉积过程中基体温度保持在150℃。研究了ZnO薄膜中铝的质量分数与薄膜电学性能和发光性能的关系。结果表明,掺杂铝的质量分数为1.37%时所获得的ZnO薄膜具有最小的电阻率和较强的紫外发光特性。