PZT铁电薄膜的低温原位生长

在溅射法预制备的LaNiO3/Si基片上,用射频溅射法在较低的衬底温度(235～310℃)和纯Ar气氛中原位生长Pb(Zr0.52Ti0.48)O3(PZT)薄膜.通过优化溅射功率、基片温度等工艺,最后在260℃的较低基片温度上成功制备出具有良好铁电性的PZT薄膜.使用X射线衍射(XRD)测试样品的结构,原子力显微镜观察其表面形貌,TD-88A标准铁电测试系统测试样品(Ar/PZT/LNO结构)的铁电性能.结果表明:(1)溅射功率110W,基片温度260℃时,原位沉积的PZT呈(111)、(200)取向;(2)上述工艺制备的PZT薄膜展现良好的铁电性,在5V测试电压时,其剩余极化为23.1uc/cm2,漏电流密度为1.34×10-4A/cm2.     

温度对飞秒激光沉积ZnO/Si薄膜的结构和性能的影响

通过飞秒脉冲激光(50 fs,800 nm,1 kHz,2 mJ)沉积技术在n型Si(100)单晶基片上制备了ZnO薄膜.详细研究了基片温度变化以及退火处理对ZnO薄膜的结构、表面形貌及光学性质的影响.X射线衍射(XRD)结果表明,不同温度下(20~350℃)生长的ZnO薄膜具有纤锌矿结构,并且呈c轴择优取向;当基片温度为80℃时,薄膜沿(002)晶面高度择优生长;当基片温度为500℃时薄膜沿(103)晶面择优生长,场发射扫描电子显微镜(FEEM)结果表明薄膜呈纳米晶结构,并观察到了ZnO的六方结构.进一步通过透射光谱的测量讨论了基片温度及退火处理对ZnO薄膜光学透射率的影响,结果表明退火后薄膜的透射率增大.     

退火对ZnO薄膜结构及缺陷的影响

采用射频反应磁控溅射法在Si(111)基片上制备了高度c轴择优取向的ZnO薄膜,采用X线衍射(XRD)、X线光电子能谱(XPS)分析方法研究了退火对ZnO薄膜结构及缺陷的影响.结果表明,随着退火温度的上升,薄膜的择优取向及取向一致性更好,晶化程度增高,晶粒尺寸变大.退火使更多的Zn间隙原子回到晶格位置,并弥补薄膜中氧的...     

退火温度对NiZn铁氧体薄膜性能的影响

用溶胶-凝胶(Sol-Gel)法在Si(100)基片上沉积了NiZn铁氧体薄膜,研究了退火温度对薄膜结构和磁性能的影响.XRD研究表明,薄膜具有立方尖晶石结构,但当退火温度为900 ℃时,有SiO2相出现,发生了明显的Si扩散.原子力显微镜(AFM)究表明,退火温度升高,薄膜晶粒尺寸逐渐变大,粗糙度相应增加.随着退火温度的升高,薄膜的饱和磁化强度(Ms)呈先增加后降低的趋势,而矫顽力(Hc)与Ms变化相反.当退火温度为700 ℃时,薄膜具有最优磁性能,Ms=360×103 A/m,Hc=6 764 A/m.     

垂直靶向脉冲激光沉积制备ZnO纳米薄膜

用一种新颖的制备纳米粒子与薄膜的垂直靶向脉冲激光沉积(VTPLD)方法,在室温及空气气氛下,于玻璃基底上成功地制备出ZnO纳米薄膜.用扫描电子显微镜(SEM)和X射线衍射(XRD)仪对ZnO纳米薄膜的表面形貌和结构进行了表征,用荧光光谱仪对薄膜的光致发光(PL)性能进行了测量.结果表明,当激光功率为13 W时,沉积出的粒子大小较均匀,尺寸在40 nm左右,且粒子排列呈现出一定方向性;当激光功率为21 W时,沉积的ZnO纳米薄膜图呈现出微纳米孔的连续薄膜.在玻璃基底上沉积的ZnO纳米薄膜有一主峰对应的(002)衍射晶面,表明ZnO纳米薄膜具有良好的c轴取向性.不同激光功率下沉积ZnO纳米薄膜经500 ℃热处理后的PL峰,其强度随激光能量而变化,最大发光波长位于412 nm.     

溅射功率对Mg2Si薄膜制备的影响

采用射频磁控溅射系统,在Si(111)衬底上制备了不同溅射功率下的Mg2Si薄膜。通过X线衍射(XRD)和冷场发射电子显微镜镜(FESEM)对Mg2Si薄膜的晶体结构和表面形貌进行了表征,理论分析了Mg2Si薄膜在Si(111)衬底上的外延生长关系,得到了Mg2Si薄膜的外延生长特性。研究结果表明,在80～110 W的溅射功率范围内,Mg2Si薄膜具有Mg2Si(220)的外延择优生长特性,并且随着溅射功率的增加Mg2Si(220)衍射峰先增强后变弱,在100W功率下Mg2Si(220)衍射峰最强。     

脉冲激光沉积β-FeSi2/Si(111)薄膜的工艺条件

用FeSi2合金靶作为靶材,采用准分子激光沉积法在Si(111)单晶基片上制备了单相的-βFeSi2薄膜,并将飞秒脉冲激光沉积法(PLD)引入到-βFeSi2薄膜的制备工艺中;用X射线衍射仪(XRD),场扫描电镜(FSEM),能谱仪(EDS),紫外可见光光谱仪研究了薄膜的结构、组分、表面形貌和光学性能。基片温度为500℃,采用KrF准分子脉冲激光沉积法可获得单相的-βFeSi2薄膜。衬底温度为550℃时,-βFeSi2出现迷津状薄层。采用飞秒脉冲激光法-βFeSi2薄膜的合成温度比准分子脉冲激光沉积法制备温度低50~100℃;薄膜的晶粒分布均匀连续,没有微米级的微滴;飞秒脉冲激光沉积效率比准分子激光的高1000倍以上,是一种快速高效的-βFeSi2薄膜沉积技术。     

PLD法制备ZnO薄膜的退火特性和蓝光机制研究

通过脉冲激光沉积(PLD)方法,在O2中和100～500℃衬底温度下,用粉末靶在Si(111)衬底上制备了ZnO薄膜,在300℃温度下生长的薄膜在400～800℃温度和N2氛围中进行了退火处理,用X射线衍射(XRD)谱、原子力显微镜(AFM)和光致发光(PL)谱表征薄膜的结构和光学特性。XRD谱显示,在生长温度300℃时获得较好的复晶薄膜,在退火温度700℃时获得最好的六方结构的结晶薄膜;AFM显示,在此退火条件下,薄膜表面平整、晶粒均匀;PL谱结果显示,在700℃退火时有最好的光学特性。     

Al薄膜对(002)ZnO/Al/Si结构基片中ZnO薄膜特性影响的实验研究

采用射频磁控溅射法沉积制备了(002)ZnO/A l/Si复合结构。研究了Al薄膜对(002) ZnO/Al/Si复合结构的声表面波器件(SAWD)基片性能影响以及当ZnO 薄膜厚度一定时的Al膜最佳厚度。采用X射线衍射(XRD)对Al和ZnO薄膜进行了结构表征 ,采用 扫描电镜(SEM)对ZnO薄膜进行表面形貌表征,并从薄膜生长机理角度进行了分析。结果 表明,加Al薄膜有利于ZnO薄膜按(002)择优取向生长,并且ZnO 薄膜的结晶性能提高;与(002)ZnO/Si结构基片相比,当Al薄膜 厚为100nm时,(002)ZnO/Al/Si结构中ZnO薄 膜的机电耦合系数提高 了65%。     

溅射功率对AlN薄膜结构形貌的影响

采用直流反应磁控溅射法在Si(111)基片上制备了AlN薄膜,利用X线衍射(XRD)、场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)对不同溅射功率下制备的AlN薄膜的结构及形貌进行了分析表征。结果表明:在一定范围内,随着溅射功率的增大,薄膜厚度增加,晶粒逐渐长大,表面粗糙度也随之增大;AlN(002)择优取向改善明显,120W时达到最佳。     

Capacitance-voltage characterization of pulsed plasma polymerized allylamine dielectrics for flexible polymeric field effect transistors

Polyallylamine films, deposited on Si wafers by radio frequency (RF) pulsed plasma polymerization (PPP), were employed as insulating layers of metalinsulator-semiconductor (MIS) capacitors. The insulating polymer films were deposited at plasma reactor temperatures of 25°C and 100°C. Multiple frequency capacitance-voltage (C-V) measurements indicated that an in-situ heat treatment during film deposition increased the insulator dielectric constant. The dielectric constant, calculated from the C-V data, rose from 3.03 for samples with no heat treatment to 3.55 for samples with an in-situ heat treatment. For both sample sets, the I-V data demonstrates a low leakage current value (<20 fA) up to 100 V. Capacitance-time (C-t) measurements were also used to characterize the mobile ions in the polymer that migrate over time with applied voltage. Results indicate that the polymer layers contain few electrically active defect centers and virtually no pinholes. Hysteresis in the C-V curves with differing sweep directions was more pronounced for in-situ heat-treated samples indicative of mobile charge.     

激光熔蚀反应淀积AlN薄膜残余应力及热稳定性的研究

激光熔蚀反应淀积于 Si(10 0 ) ,Si(111)基底上的 Al N薄膜是高质量高取向性的 Al N多晶膜 ,薄膜与基底的取向关系为 Al N(10 0 )∥ Si(10 0 ) ,Al N(110 )∥ Si(111)。薄膜具有较低的残余应力和较好的热稳定性。实验结果表明 ,当氮气压强和放电电压分别为 10 0× 133.33Pa和 6 50 V时 ,薄膜的残余应力低于 3GPa。此样品在纯氧环境 50 0℃时 ,经过 3h的退火 ,红外吸收谱检测未发现有Al2 O3 特征峰出现。对 Al N/Cu双层膜的研究表明所制备的 Al N薄膜在金属薄膜的防护上也有潜在的应用价值。     

TiO2薄膜的热处理晶化及形貌研究

对Si(111)和Si(100)衬底上用化学气相沉积法制成的TiO2薄膜进行了不同温度的热处理，并用原子力显微镜对处理后薄膜的形貌变化进行了观察。X－射线衍射分析表明形貌变化过程即晶化过程。晶化物相为金红石。晶化程度（或形貌变化程度）与热处理的温度有次数（或热处理时间）有关。Si(111)衬底上TiO2晶化形貌为杂乱分布的柱状、板状，定向不好；而Si(100）衬底上TiO2晶化形貌为定向较好的四方柱状或板状，这是因为Si(100)与金红石（001）都属四方对称结构，两相结构在此方向上容易匹配的结果。在相同热处理条件下，Si(111)衬底比Si(100)衬底上TiO2晶化程度高，说明非定向附生的晶化作用比定向附生的晶化作用容易实现。     

溅射沉积AlN薄膜结构与基片种类的关系

采用高真空直流磁控反应溅射成功地在５种基片上制备出多晶择优取向的ＡＩＮ薄膜。结果表明,５种基片均可生长（１００）面掺优取向的ＡＩＮ薄膜,并且具有良好的纵向组成均匀性,表面粗造度小,晶粒均匀致密。在金属电极和Ｓｉ片上沉积的ＡＩＮ薄膜结晶度、取向性、衍射强度差别较小,两者的结构均优于在盖玻片上的沉积的ＡＩＮ薄膜。     

Growth of diamond films on si(100) with and without boron nitride buffer layer

Diamond films were grown on Si(100) and boron nitride deposited Si(100) substrates using hot filament chemical vapor deposition (HFCVD) technique. Microstructure and morphology of diamond films have been investigated systematically as a function of CH₄ and H₂ ratio and the ambient pressure. The deposited films were characterized by employing techniques such as scanning electron microscopy (SEM) and laser Raman spectroscopy. The average size and growth rate of diamond particles were found to increase with the CH₄ to H₂ ratio and decrease with the ambient pressure. Maximum growth rate of synthetic diamond deposited on Si(100) was found to be &#x223C;3.5 &#x00B5;m/hr for the film deposited at 20 Torr with CH₄:H₂ &#x223C; 1.5:100 (substrate temperature &#x223C;850&#x00B0;C). In most of these depositions, the morphology of the diamond crystals was cubic with significant secondary nucleation at higher methane concentrations and ambient pressure. The diamond film deposited on Si(100) with BN buffer layer shows an improvement in growth rate and the coverage, and the secondary nucleation was found to be substantially reduced, resulting in relatively smooth morphology. MicroRaman investigations show less amorphous graphite formation and better structural quality of diamond film than the one deposited without the BN buffer layer. On leave from Department of Physics University of Poona, Pune-411007 INDIA     

低失真MnZn铁氧体中ZnO含量对磁特性的影响

为了提高非对称数字用户线(ADSL)接入系统的网络传输质量,采用传统氧化物陶瓷工艺制备了低失真MnZn铁氧体,并研究了在Fe2O3含量不变的前提下,ZnO含量与其磁特性的关系。结果表明:适量的ZnO可以提高起始磁导率μi,降低磁滞常数ηB。随着ZnO含量的增加,μi值先增大后减少,截止频率fr先减少后增加。当x(ZnO)为23%时,其μi=8 100,ηB=0.42×10–6/mT。     

Properties of CdTe nanocrystalline thin films grown on different substrates by low temperature sputtering

CdTe nanocrystalline thin films have been prepared on glass, Si and Al2O3 substrates by radio-frequency magnetron sputtering at liquid nitrogen temperature. The crystal structure and morphology of the films were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The XRD examinations revealed that CdTe films on glass and Si had a better crystal quality and higher preferential orientation along the (111) plane than the Al2O3. FESEM observations revealed a continuous and dense morphology of CdTe films on glass and Si substrates. Optical properties of nanocrystalline CdTe films deposited on glass substrates for different deposited times were studied.     

不同衬底上纳米晶CdTe薄膜的低温制备及光性能研究

CdTe nanocrystalline thin films have been prepared on glass, Si and Al2O3 substrates by radio-frequency magnetron sputtering at liquid nitrogen temperature. The crystal structure and morphology of the films were charac-terized by X-ray diffraction （XRD） and field-emission scanning electron microscopy （FESEM）. The XRD examinations revealed that CdTe films on glass and Si had a better crystal quality and higher preferential orientation along the （111） plane than the Al2O3. FESEM observations revealed a continuous and dense morphology of CdTe films on glass and Si substrates. Optical properties of nanocrystalline CdTe films deposited on glass substrates for different deposited times were studied.     

Surface and sensing properties of PE-ALD SnO/sub 2/ thin film

SnO/sub 2/ thin films have been deposited by plasma enhanced-atomic layer deposition (PE-ALD) on Si (100) substrate. The dominant oxygen species for post-annealing films were O/sub 2//sup -/, O/sup 2-/ and O/sup -/ for 100, 200 and 400 cycles, respectively. The film for 200 cycles has a good CO sensing property at the highest concentration of O/sup 2-/ species.     

Deposition and characterization of Si-rich silicon oxide films using HMDS for integrated photonics

Silicon-rich silicon oxide (SRSO) films were deposited using thermal-CVD system with organic precursor hexamethyldisilazane (HMDS) and oxygen (O₂) at the temperature range of 760–820 °C. The deposited SRSO films were characterized by using ellipsometry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX). The effect of deposition temperature on the physical and optical properties of deposited SRSO films has been studied and analyzed. It has been observed that the refractive index (RI) of the deposited films increases while the stress of compressive nature decreases with the corresponding increase in deposition temperature. The peak positions of Si–O–Si stretching bond and the full-width at half maxima (FWHM) of these peaks have been investigated by using FTIR spectroscopy. It was found that the peak position of Si–O–Si stretching bond move toward lower wave number while the corresponding FWHM increases with increase in the deposition temperature. The peak intensities of Si–H, O–H and Si–OH bonds decrease with corresponding increase in deposition temperature, which signifies an improvement in the quality of the deposited SRSO films. The SEM and EDAX analysis clearly reveals the successful deposition of SRSO films with some dense clusters of silicon having size about 500 nm on the surface of the deposited films.