H2稀释度对HFCVD法沉积SiC薄膜结晶度的影响

采用热丝化学气相沉积(HFCVD)技术,以甲烷(CH4)和硅烷(SiH4)作为源反应气体在Si(111)衬底上生长了晶态SiC薄膜.通过X射线衍射(XRD)、傅立叶红外(FTIR)等分析手段对样品结构、组分进行了分析.通过提高H2稀释度,使得SiC薄膜的质量得到了改善.选取高H2稀释度,利用原子氢在成膜过程中的刻蚀作用稳定结晶相,可在较低的衬底温度下,沿Si(102)择优取向异质生长出晶态SiC薄膜.     

热丝化学气相沉积(HFCVD)制备纳米晶态SiC紫外发光特性研究

采用热丝化学气相沉积(HFCVD)技术在Si(111)衬底上生长了SiC薄膜.通过电子能谱(EDX)、X射线衍射(XRD)和时间分辨光谱等分析手段对样品结构、组分进行了分析.实验结果表明所制备的样品为纳米晶态SiC,并通过计算得到验证,对所制备样品进行光致发光特性测试,观察到其在室温下有较强的紫外发光.     

离子注入形成SiC纳米颗粒的发光性能研究

用离子注入法将Si、C离子注入到非晶二氧化硅中,样品分别在600 ℃,800 ℃和1 100 ℃进行了退火,并在1 100 ℃时作了1 h、2 h、3 h和4.5 h的退火.用透射电镜(TEM)和光致发光(PL)研究了退火温度以及退火时间对样品的微结构和发光特性的影响.实验表明,退火后样品中形成了SiC纳米颗粒,PL谱中观察到了缺陷和SiC纳米颗粒的发光.     

SiC薄膜生长过程中的偏压作用

采用分步偏压溅射法,在Si(100)衬底上制备了高质量的SiC薄膜. 傅里叶红外(FTIR)光谱测试表明,分步偏压法不仅有利于提高SiC薄膜的生长速率,同时也有利于SiC薄膜的成核生长. 通过原子力显微镜(AFM)观察到,单一偏压法制备的样品表面有许多的凹坑,而分步偏压法制备的样品表面则没有出现明显的凹坑. 因此,采用分步偏压溅射法不仅可以提高薄膜的生长速率,同时也可以减小对薄膜的离子刻蚀作用,改善薄膜的质量.     

SiC(N)/Si3N4吸波材料的制备与性能

通过掺杂纳米SiC(N)吸收剂，采用无压烧结工艺，制备了SiC(N)／Si3N4复合型吸波材料。对材料进行了XRD、SEM及强度分析，结果表明：随着纳米吸收剂SiC(N)加入量的增加，材料的烧结性能趋于下降，表现为α-Si3N4的含量增多，柱状β-Si3N4的尺寸变小，材料气孔增大，强度降低。     

放电等离子体烧结SiC/Cu金属陶瓷复合材料研究

选用SiC/Cu包裹复合粉体,采用最新型的放电等离子体烧结方式制备了SiC/Cu金属陶瓷复合材料.分别采用XRD、SEM等方法对烧成样品进行表征.结果表明,放电等离子体烧结过程中,由于等离子体的作用,不同的烧成温度使得烧成样品中的物质及相应的含量发生变化.样品的密度随温度升高而增大,而硬度在730℃左右出现最大值,这是采用放电等离子体烧结制备SiC/Cu金属陶瓷复合材料的最佳烧成温度.由于SiC的增强作用,使得SiC/Cu金属陶瓷复合材料的硬度远远高于Cu.     

SiC/Cu纳米包裹粉体及其复合材料的制备

选用工业生产的SiC亚微米粉体,利用置换反应制备纳米Cu.采用直接还原-旋转沉淀工艺制备SiC/Cu包裹粉体.采用气氛烧结获得金属陶瓷复合材料.分别通过AES、XRD、SEM等分析方法对原始SiC粉体、包裹复合粉体和烧成样品进行表征.结果表明:包裹复合粉体具有"核-壳"结构,由于Cu的自发氧化使得复合粉体中出现Cu2O.包裹结构中SiC颗粒抑制了烧结过程中Cu的晶粒生长,从而使烧结样品呈现纳米结构.     

磷掺杂碳化硅的制备及其影响因素

以葡萄糖粉剂为碳源,沉淀白炭黑为硅源,磷酸为掺杂源,通过碳热还原法制备了磷掺杂碳化硅(SiC)。并利用X射线衍射仪、紫外可见吸收光谱仪、扫描电子显微镜、比表面积测试仪等对不同合成温度、不同掺杂浓度下所制备样品物相组成、微观形貌以及性质进行了表征。结果表明,磷原子进入SiC晶格,形成了磷掺杂3C-SiC。所制备的SiC样品与白炭黑的微观结构相似,其一次粒子平均粒径约150 nm,最高比表面积84.4 m~2/g。当n(P)∶n(Si)≥0.01时,掺杂达到饱和。随着温度升高,SiC禁带宽度降低,1 350℃后变化微弱,1 400℃时,比表面积最大。合成磷掺杂SiC的原料廉价易得,工艺简单,有望实现工业化生产。     

碳化硅凝胶注模浆料的研究进展

在分析陶瓷浆料稳定分散机制的基础上,从碳化硅(SiC)粉体表面改性和分散剂处理两方面探讨了凝胶注模工艺中高固相含量、低黏度的SiC陶瓷浆料的制备问题.综述了SiC表面改性及其几种常见分散剂的研究进展,并指出今后研究中需要解决的问题.     

SiC多型体的电子结构和光学特性研究

在局域密度近似下,采用平面波超软赝势法对SiC多型体的能带和光谱特性进行了研究.计算了4种SiC多型体的能带、介电常数等并进行了比较.计算表明4H-SiC导带最低点在布里渊区M点,6H-SiC导带最低点在布里渊区ML线上U(0,0.176,0)(2π/a)点.在布氏区垂直于Z轴方向的AH和LH段能带是二重简并的.能带得介电常数的计算表明SiC是各向异性材料.局域密度近似下的密度泛函理论对能隙的计算结果小于实验结果.     

Influence of the Plasma State on the Formation of Nano Crystalline SiC Films

The influence ofthe plasma state on the microstructure transformation from amorphousto nanocrystalline state is emphasized during the formation of the silicon carbide (SIC) films deposited by the plasma enhanced chemical vapor technique. The effect of two key parameters, the working pressure and hydrogen concentration in the gas flow, that perform the dependence by modulating the two essential factors of the plasma stateions energy and gas composition, is in-depth investigated. The experimental results showed that nanocrystalline SiC films fit for field emitters could be achieved under an appropriate ion energy flow density and gas components in the plasma.     

Electroless copper-phosphorus coatings with the addition of silicon carbide （SiC） particles

Cu-P-silicon carbide(SiC)composite coatings were deposited by means of electroless plating.The effects ofpH values,temperature,and different concentrations of sodium hypophosphite(NaH2PO2·H2O),nickel sulfate(NiSO4·6H2O),sodium citrate(C6H5Na3O7·2H2O)and SiC on the deposition rate and coating compositions were evaluated,and the bath formulation for Cu-P-SiC composite coatings was optimised.The coating compositions were determined using energy-dispersive X-ray analysis(EDX).The corresponding optimal operating parameters for depositing Cu-P-SiC are as follows:pH 9; temperature,90℃; NaH2PO2·H2O concentration,125 g/L; NiSO4·6H2O concentration,3.125 g/L; SiC concentration,5 g/L; and C6H5Na3O7·2H2O concentration,50 g/L.The surface morphology of the coatings analysed by scanning electron microscopy(SEM)shows that Cu particles are uniformly distributed.The hardness and wear resistance of Cu-P composite coatings are improved with the addition of SiC particles and increase with the increase of SiC content.     

多晶SiC/多孔硅结构材料的APCVD生长及表征

采用SiH₄-C₃H₈-H₂气体反应体系,通过常压化学气相淀积(APCVD)工艺在电化学腐蚀的多孔硅衬底上进行了多晶3C-SiC薄膜的生长,研究了多孔硅孔隙率对薄膜生长质量的影响．实验结果表明,当多孔硅孔隙率较低时,得到的是含有SiC(111)晶粒的多晶硅薄膜,随着孔隙率的增加,生长薄膜由富碳多孔SiC向多晶SiC薄膜过渡,表面平整度增加,并具有<111>晶向择优生长的特点．     

Elimination of Voids at Interface of <Emphasis Type="Italic">β</Emphasis>-SiC Films and Si Substrate by Laser CVD

Void-free β-SiC films were deposited on Si(001) substrates by laser chemical vapor deposition using hexamethyldisilane (HMDS) as the precursor. The effect of the time of introducing HMDS, i e, the substrate temperature when HMDS introduced (T_in), on the preferred orientation, surface microstructure and void was investigated. The orientation of the deposited SiC films changed from <001> to random to <111> with increasing T_in. The surface showed a layer-by-layer microstructure with voids above T_in ? 773 K, and then transformed into mosaic structure without voids at T_in= 298 K. The mechanism of the elimination of voids was discussed. At T_in =298 K, Si surface can be covered by an ultrathin SiC film, which inhibits the out-diffusion of Si atoms from substrate and prohibites the formation of the voids.     

3C—SiC单晶薄膜的干法刻蚀研究

以四氟化碳（CF4）和CF4 O2作为刻蚀气体,对外延3C-SiC单晶薄膜进行了系统的等离子体刻蚀研究。结果表明薄膜刻蚀速率在气体流量一定的情况下与O2/CF4流量比有关：当O2/CF4流量比为40%左右时,刻蚀速率达到量大值;O2/CF4流量比低于40%,不仅刻蚀速度降低而且还在被刻蚀样品表面形成暗表面层,俄歇能谱（AES）分析表明暗层为富C表面的的残余SiC,AES分析还证实改变工艺条件可以消除富C表面的文中还给出了经图形刻蚀后的样品的表面形貌（SEM）照片。     

Growth,Characterization and Micro-pattern Fabrication of Iridium/Si3N4/Si（100） Thin Films

Iridium thin films have been deposited on Si3N4（100 nm）/Si（100） substrates by magnetron sputtering. And then iridium film micro-patterns were fabricated by ion milling technique. The atomic force microscopy （AFM） measurements reveal that there is a very fiat and smooth surface with an average roughness of 0.64 nm for the iridium films. The X-ray diffraction also reveals that the deposited iridium films have a polycrystalline microstructure with （111） plane preferential orientation. The electrical resistivity of the iridium films was also measured and discussed.     

PAHFCVD金刚石膜表面形貌的研究

采用等离子辅助热丝化学气相沉积(PAHFCVD)装置进行了金刚石薄膜、碳化钛/金刚石复合膜、掺硼金刚石薄膜的制备。制备条件分别为:V(CH)4∶V(H2)=3∶100,载气流量5~50 cm3.s─1,钛源钛酸异丙酯(Ti[OC3H7]4),硼源硼酸三甲酯(BC3O4H9),基体温度820~860℃,基体偏压300 V,沉积气压4 kPa。运用扫描电子显微镜(SEM)、X射线衍射(XRD)和能量扩散电子谱(EDX)等分析手段对PAHFCVD金刚石膜、金刚石复合膜和掺硼金刚石膜进行了表征。结果发现,金刚石/碳化钛膜和掺硼金刚石膜主要晶面为(111)面。     

Electron Spectroscopy Studies on SiC Films before and after Hydrogen Ion Irradiation

1Introduction Theinteractionbetweenenergetichydrogenandlow Zmaterials,suchasSiC,hasbeenstudiedinseveral groupsbecausecarbidesoflowZelementsareusedfor plasmafacingcomponentsasfirstwallmaterialsin Tokamak[1,2].Hence,itisofinteresttounderstandthe effectsofHp…