SiC／Si异质生长的研究

在半导体材料中，ＳｉＣ比Ｓｉ具有更优越的物理特性、化学特性和半导体特性，在高温、高频和功率器件制造中有十分广阔的应用前景．但是它的材料制备很困难．文中在理论分析基础上，以Ｓｉ为衬底，用常压化学气相淀积（ＡＰＣＶＤ）技术，在温度为１１００℃下，生长出ＳｉＣ多晶薄膜，样品用ＡＥＳ和Ｘ－射线衍射进行了测试和分析     

LPCVD多晶硅薄膜的晶体结构

本文研究了用于制作压阻元件的LPCVD多晶硅薄晶体结构与淀积温度,膜厚及热处理温度的关系。多晶硅薄膜的织构和晶粒度不仅与淀积温度有关,而且与膜厚有着密切的关系,1000℃以上的高温热处理具有增大晶粒度和减小薄膜在淀积过程中形成的晶粒优先取向的作用。     

氧化铝缓冲层对ZnO薄膜性质的影响

采用反应磁控溅射的方法在石英衬底上制备了一层AI2O3薄膜,并将其作为后续ZnO薄膜生长的缓冲层.然后,采用反应磁控溅射的方法在AI2O3缓冲层上制备了ZnO薄膜.对比研究了引入Al2O3缓冲层前后,ZnO薄膜的结构和光学特性.通过引入Al2O3缓冲层,发现ZnO薄膜样品的(002)方向X射线衍射峰的半峰宽(FWHM)明显减小,光致发光谱中与缺陷相关的可见发光峰强度明显减弱,吸收光谱中的吸收边变得更加陡峭.这些结果表明引入Al2Q3缓冲层后,ZnO薄膜的结构和光学特性得到了很大改善,为制备高质量ZnO薄膜提供了参考.     

硅基3C-SiC薄膜的外延生长技术

用常压化学气相淀积法在（１００）Ｓｉ衬底上异质外延生长了３Ｃ－ＳｉＣ薄膜。为减小３Ｃ－ＳｉＣ与硅之间的晶格失配,在化学气相淀积系统中通过对硅衬底表面碳化制备了缓冲层,确定了形成缓支的最佳条件。测量结果表明,１３００℃下在Ｓｉ℃衬底缓冲层上可以获得３Ｃ－ＳｉＣ单晶。     

HfO2高激光损伤阈值薄膜的制备及特性研究

采用水热合成技术,制备了HfO2胶体,用旋涂法镀制了单层HfO2介质膜.采用XRD,椭偏仪,红外光谱(FTIR)等方法对薄膜进行了测试和表征,用输出波长为1 064 nm,脉宽为10 ns的电光调Q激光系统产生的强激光测试其激光损伤阈值.研究了热处理温度对薄膜厚度、折射率、红外光谱、晶态以及激光损伤阈值的影响,并对薄膜的激光损伤形貌进行了分析.研究结果表明HfO2薄膜的折射率可达到1.655;采用150 ℃左右的温度对薄膜进行热处理可以提高薄膜的激光损伤阈值,此时薄膜的激光损伤阈值高达42.32 J/cm2(1 064 nm,10 ns),大大高于物理法制备的HfO2薄膜的激光损伤阈值(8.6 J/cm2,1 064 nm,12 ns).     

射频磁控反应溅射制备HfO2薄膜的工艺及电性能

采用射频磁控反应溅射法,以高纯Hf为靶材、高纯O2为反应气体,成功地在p型硅衬 底上制备了高k栅介质HfO2薄膜,并对薄膜的沉积速率、成分和电学性能进行了研究.结果 表明,薄膜沉积速率随射频功率增加而增大,随O2气流量增加而减小,随溅射气压增加呈先 增大后减小的趋势.制备的薄膜中Hf和O元素的原子浓度比基本符合化学计量比.研究了薄 膜的C-V特性;获得了O2流量、射频功率及退火温度对薄膜电学性能的影响规律.     

快速退火对HfO_2高k薄膜结构和电学性能的影响

文章采用射频反应磁控溅射法在p型Si(100)衬底上制备了HfO2高k薄膜,并对样品进行了N2气氛快速退火处理。对薄膜进行了Raman光谱、UV-VIS-NIR透过光谱、XPS以及C-V特性的分析,研究了快速退火对HfO2薄膜结构、成分、禁带宽度和电学特性的影响。结果表明,HfO2薄膜有良好的非晶稳定性,组分基本符合化学剂量比。经N2气氛快速退火处理后,薄膜的化学剂量比得到改善,禁带宽度增大,且薄膜内的固定电荷密度和平带电压偏移减小。     

直流磁控溅射铂电阻薄膜

根据薄膜理论和通过成膜工艺实验,研究了影响铂薄膜电阻温度系数的主要因素。1)对铂靶材料的纯度要求高,含杂质极少;2)淀积薄膜要有一定厚度,通常近于1μm才能有较大的α;3)成膜以后,需经过高温热处理,减少缺陷,结晶化改善。通过大量实验,使用高铝陶瓷基片或微晶玻璃基片,溅射铂薄膜的厚度为800nm,高温热处理1h,可以获得电阻温度系数为3.850×10-3/℃的铂电阻薄膜。     

采用Cu/Ti过渡层沉积金刚石薄膜刀具的界面结构

研究了硬质合金基底上Cu/Ti作过渡层化学气相沉积(CVD)金刚石薄膜的界面特性.利用激光Raman谱分析了过渡层不同生长阶段金刚石薄膜的质量的影响.采用SEM、EDS对金刚石薄膜硬质合金刀具横截面的结构进行了研究.结果表明:基体中的Co被Cu/Ti作过渡层有效的抑制住;Cu向基体内的扩散改善了基体的性能,提高了界面层金刚石薄膜的质量;Ti的引入促进了金刚石的形核,减少了界面处晶粒间的空隙,提高了金刚石薄膜与基体表面的实际接触面积.     

光CVD-SiO_2薄膜的研究

本文论述了光化学气相淀积(光CVD)SiO_2薄膜的原理及方法。用光CVD技术在50～200℃条件下,在Si、InSb及HgCdTe晶片上淀积了SiO_2薄膜。对薄膜的物理性质和化学性质进行了讨论。结果表明:光CVD技术在半导体低温化工艺中将很有前途。     

Investigations of ZnO thin films deposited by a reactive pulsed laser ablation

Highly transparent ZnO thin films were deposited at different substrate temperatures by pulsed laser deposition in an oxygen atmosphere. The thin films were characterized by various techniques including X-ray diffraction, scanning electron microscopy, optical absorption, and photoluminescence. We demonstrated that oriented wurtzite ZnO thin films could be deposited at room temperature using a high purity zinc target. Variable temperature photoluminescence revealed new characteristics in the band edge emission. The underlying mechanism for the observed phenomena was also discussed.     

新型HfO2栅介质电特性的理论分析与实验研究

对结合NH₄F表面预处理和高温退火新型工艺制作的超薄HfO₂栅介质MOS电容的C-V特性进行了模拟仿真和实验研究,理论分析的界面态分布与实验结果吻合．利用高频C-V法计算了平带电压漂移量、氧化层内陷阱电荷密度和界面态密度,比较了不同工艺条件下样品的电参数．结果表明NH₄F表面预处理和高温退火新型工艺可以显著降低界面态和氧化层陷阱电荷,从而降低栅极漏电流．     

热作用对喷射沉积Mg-7Al-1.5Zn-4.5Ca-1Nd合金坯组织的影响

采用喷射沉积方法制备了Mg-7Al-1.5Zn-4.5Ca-1Nd合金,通过对沉积态合金不同温度加热处理后试样的组织观察,分析了此合金的相变及组织演变特征。结果表明:喷射沉积坯晶粒细小,组织分布均匀,组织中含有α-Mg、Mg17Al12、MgZn2、Al2Ca和Ca2Mg6Zn3等相;当加热温度从350℃升到520℃时,喷射沉积坯组织有明显的变化,Mg17Al12相溶解,Ca2Mg6Zn3分解为Mg2Ca和MgZn2相,高温时析出了新相Mg12Nd;且硬度随着加热温度的升高而持续下降。     

Influence of crystal structure on friction coefficient of ZnO films prepared by atomic layer deposition

In this work, the influence of crystal structure on the friction coefficient of zinc oxide(ZnO) films was studied. The ZnO films were deposited on a Si(100) substrate using an atomic layer deposition process, and the crystal structure of the ZnO films was changed by adjusting the substrate temperature. The surface morphology and the crystal structure of the Zn O films were measured by an atomic force microscope and an X-ray diffractometer, respectively, and the friction coefficient of the ZnO films was measured by a ball-on-disk dry sliding tester. The results show that the ZnO films deposited at substrate temperatures below 200°C are dominated by(100),(002) and(101)-orientated crystals, while the ZnO films deposited at substrate temperatures above 250°C are dominated by(002)-orientated crystals, and that the crystal structure influences the friction coefficient of ZnO films greatly. The ZnO films with(002)-orientated crystals possess a larger friction coefficient than those with other orientated crystals. In order to verify this conclusion, we measured the friction behavior of the ZnO single crystals with different orientations. The results are consistent well with our conclusion.     

Microstructure and Dielectric Property of 3D BN_f/Si_3N_4 Fabricated by CVI Process

As potential wave-transparent materials applied at high temperatures, 3D BN_f/Si_3N_4 ceramic matrix composites were prepared by low pressure chemical vapor infiltration or deposition(LPCVI/CVD) process from SiCl_4-NH_3-H_2-Ar gas precursor at 800 oC. The densification process, microstructure and dielectric properties of 3D BN_f/Si_3N_4 composites were investigated. The results indicated that 3D BN_f/Si_3N_4 was successfully fabricated by LPCVI/CVD, with final open porosity of 2.37% and density of 1.89 g/cm~3. Densification kinetics of 3D BN_f/Si_3N_4 is a typical exponential pattern. The Si_3N_4 matrix was uniformly infiltrated into porous BN_f preform. The deposited Si_3N_4 matrix was amorphous by XRD analysis. Introduction of BN fiber into Si_3N_4 ceramic lowered the permittivity of Si_3N_4. The fabricated BN_f/Si_3N_4 composites possess low permittivity of 3.68 and low dielectric loss of lower than 0.01, which are independent of temperature below400 oC. Transmission coefficient of BN_f/Si_3N_4 composite is 0.57 and keeps stable below 400 oC. BN_f/Si_3N_4 can be fabricated at low temperature and may be candidates for the microwave transparent materials.     

BiSI棒状纳米晶薄膜的物性研究

采用改进的喷雾热解方法——异步脉冲超声喷雾热解法（APUSP），以BiCl3、硫脲和碘溶液为前驱液，在非晶衬底上成功地制备了BiSI纳米棒阵列薄膜．对采用异步脉冲超声喷雾热解法所制备的棒状BiSI纳米晶薄膜样品的介电特性和光吸收特性进行了测试．结果表明，采用该法所制备的棒状纳米结构薄膜与传统喷雾热解法所制备的薄膜，由于结构的不同，其介电特性和可见光吸收特性具有明显的区别．该方法与传统喷雾热解法相比，所制备的纳米晶薄膜具有较高的介电常数、较小的介电损耗和较大的光吸收强度，     

Low temperature Raman study of PrCoO_3 thin films on LaAlO_3(100) substrates grown by pulsed laser deposition

Thin films of PrCoO3 were deposited on LaAlO3 substrates by pulsed laser deposition technique.X-ray diffraction result indicates that films are single phase and c-axis textured.To investigate the spin state transition,Raman spectroscopy measurements were performed at different temperatures.The position of the Raman modes is found to increase while full width at half maximum(FWHM) of these modes is found to decrease with the decrease of temperature across spin state transition temperature(220 K) of PrCoO3.     

日盲型紫外探测系滤光膜的研制

针对紫外探测系统利用紫外日盲区的特殊要求,选取HfO2和Mgf2、JGS1三种高低折射率材料组合形式。在石英基底上,采用电子束和离子辅助沉积技术及石英晶体振荡监控厚度方法。对HfO2和JGS1膜电子束沉积工艺进行了研究,对HfO2与不同材料组合的沉积工艺进行了优化,解决了膜层与基底之间附着力的问题,同时改善了Mgf2膜随厚度变化易的龟裂现象。研究了0.24~0.28μm紫外日盲波段薄膜的沉积工艺和光谱特性问题。     

Cu gettering to nanovoids in SOI materials

Silicon-on-insulator (SOI) materials have a number of inherent advantages over bulk silicon substrates owing to their high speed, low power complementary metal-oxide-semiconductor (CMOS) integrated circuits, such as immunity to radiation hardness, high speed, and high tem-perature tolerance [1]. Separation by implantation of oxygen (SIMOX), bonding and etch back (BESOI) and Smart-Cut are the leading technologies for SOI material fabrication. Transitional metal impurities such as Cu, F…     

玻璃衬底沉积氮化硅薄膜性能研究

为了改善玻璃衬底上制备的薄膜太阳电池的转换效率,采用高纯氮气作为等离子体气源,以质量分数为5%的SiH_4(Ar稀释)作为前驱气源,利用电子回旋共振-等离子体增强化学气相沉积技术在玻璃衬底上低温制备了氮化硅薄膜;利用各种测试设备分析了薄膜的成分、光学性能和表面形貌.结果表明:实验制备的非晶薄膜含氢量较低;薄膜的折射率随着衬底温度和微波功率的增加而增加.在衬底温度为350℃、微波功率为650 W时,薄膜的折射率在2.0左右,平均粗糙度为1.45 nm,还说明薄膜具有良好的光学性能和较高的表面质量.在此条件下,薄膜的沉积速率达到10.7 nm/min,表明本实验能在较高的沉积速率下制备均匀、平整、优质的SiN薄膜.