射频溅射法制备3C-SiC和4H-SiC薄膜

利用射频溅射法在Si衬底上制备了SiC薄膜，并利用x射线衍射（XRD）和红外（IR）吸收谱对薄膜的结构、成分及化学键合状态进行了分析.XRD结果表明，低温制备的SiC薄膜为非晶相，而在高温下（＞800℃），薄膜呈现4HSiC和3CSiC结晶相.IR谱显示，溅射制备薄膜的吸收特性主要为Si—C键的吸收.此外，还利用原子力显微镜对薄膜的表面形貌进行了研究，并研究了样品的场发射特性. 关键词： 射频溅射 SiC薄膜 结构 表面形貌 场发射     

在Si(111)上用有机溶胶凝胶甩膜热解法制备(0001)定向的6H-SiC薄膜

在Si(111)衬底上用聚苯乙烯溶胶凝胶甩膜并经950℃真空(10^-3Pa)热解处理法,制备出晶态SiC薄膜.用FTIR,XRD,TEM,RamanXPS等方法研究了SiC薄膜的晶体结构、微结构、组成以及各元素的化学态等性质.结果表明制得的是沿(0001)高度择优取向的晶态6H-SiC薄膜.膜中SiC晶粒沿c轴柱状生长,其最大尺寸约150nm,膜厚约为0.3μm,SiC中的Si/C比约为1.表层有少许污染C(CH和CO)和少量O(Si₂O₃,CO态氧和吸附氧).从对比实验可知,在热解时将甩膜的Si片与另一空白Si片面面相贴可明显增加SiC的生成量. 关键词： 碳化硅 薄膜 溶胶凝胶     

不同退火温度下晶化硅薄膜的电学输运性质

采用等离子体化学气相沉积技术制备氢化非晶硅薄膜,经过不同温度下的热退火处理,使薄膜由非晶结构向晶化结构转变,得到含有纳米晶粒的晶化硅薄膜.在晶化过程中,采用Raman技术对样品的结构进行表征.通过变温电导率的测试,对薄膜的电学输运性质进行了分析.研究结果表明：退火温度为700 ℃时,样品中开始有纳米晶形成,随着退火温度的增加,样品的晶化比增大,在1000 ℃时,薄膜的晶化比达到90%以上.在700 ℃退火时,薄膜中晶化成分较低,载流子的传输特性主要受到与硅悬挂键有关的缺陷态影响,表现为带尾定域态的跳跃电导 关键词： 氢化非晶硅 退火 纳米硅 电输运     

Ultrathin ZrO2 films on Si-rich SiC(0 0 0 1)-(3 × 3): Growth and thermal stability

The growth and thermal stability of ultrathin ZrO₂ films on the Si-rich SiC(0 0 0 1)-(3 × 3) surface have been explored using photoelectron spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The films were grown in situ by chemical vapor deposition using the zirconium tetra tert-butoxide (ZTB) precursor. The O 1s XAS results show that growth at 400 °C yields tetragonal ZrO₂. An interface is formed between the ZrO₂ film and the SiC substrate. The interface contains Si in several chemically different states. This gives evidence for an interface that is much more complex than that formed upon oxidation with O₂. Si in a 4+ oxidation state is detected in the near surface region. This shows that intermixing of SiO₂ and ZrO₂ occurs, possibly under the formation of silicate. The alignment of the ZrO₂ and SiC band edges is discussed based on core level and valence PES spectra. Subsequent annealing of a deposited film was performed in order to study the thermal stability of the system. Annealing to 800 °C does not lead to decomposition of the tetragonal ZrO₂ (t-ZrO₂) but changes are observed within the interface region. After annealing to 1000 °C a laterally heterogeneous layer has formed. The decomposition of the film leads to regions with t-ZrO₂ remnants, metallic Zr silicide and Si aggregates.     

Fe/Al混合膜的PLD法制备及表面分析

 采用脉冲激光气相沉积（PLD）技术制备了Fe/Al混合膜，测量了该混合膜的光电子能谱（XPS），并采用原子力显微镜（AFM）、扫描电子显微镜（SEM）对Fe/Al混合膜作了表面分析。结果表明：Fe/Al混合膜的表面粗糙度对衬底温度有明显的依赖性， 随着衬底温度的升高，薄膜的表面逐渐变得平滑，膜层变得致密，在200 ℃衬底温度下制得了均方根（rms）粗糙度为0.154 nm、具有原子尺度光滑性的Fe/Al混合膜， 膜中Fe和Al分布比较均匀，其成分比约为1∶3，同时XPS分析也表明Fe/Al混合膜暴露在空气中后表面形成了Al₂O₃和FeO氧化层。     

The structure and optical properties of SiC film on Si (111) substrate with a ZnO buffer layer by RF-magnetron sputtering technique

We have fabricated a multiply layer SiC/ZnO on Si substrates using the RF-magnetron sputtering technique with the targets of a single crystalline SiC and a polycrystalline ZnO. The as-deposited films were annealed in the temperature range of 600–1000 °C under nitrogen ambient. We have observed a strong ultraviolet (UV) emission (370 nm) from the as-deposited SiC/ZnO film and an intense violet emission (412 nm) from the film annealed at high temperature (1000 °C) under nitrogen ambient. The SiC film quality and the PL intensities are considered to be strongly dependent on the crystalline quality of the ZnO buffer layer. With the increase of the annealing temperature, the crystalline quality of the ZnO buffer layer is improved, resulting in the improvement of the SiC film quality and the increase of the PL intensities. The thin films have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to provide the evidences of photoluminescence (PL). We suggest that the UV emission could be attributed to the nanocrystal silicon particles, that the 395 nm band is related to ZnO buffer layer and has a great relation to the crystalline quality of the ZnO film, and that the violet emission is associated with the emission luminescence from 6H-SiC, which bears on the SiC film quality. The obtained results are expected to have important applications in modern optoelectronic devices.     

C+注入a-SiNx：H薄膜的微结构及光发射的研究

常温下对低压化学气相沉积制备的纳米硅镶嵌结构的a-SiN_x:H薄膜进行低能量高剂量的C⁺注入后,在800~1200℃高温进行常规退火处理。X射线光电子能谱(XPS)及X射线光电子衍射(XRD)等实验结果表明,当退火温度由800℃升高到1200℃后,薄膜部分结构由SiC_xN_y转变成SiN_x和SiC的混合结构。低温下利用真空紫外光激发,获得分别来自于SiN_x、SiC_xN_y、SiC的,位于2.95,2.58,2.29 eV的光致发光光谱。随着退火温度的升高,薄膜的结构发生了变化,发光光谱也有相应的改变。     

Pulsed laser deposition of (110) oriented semiconductive SrFeO3−x thin films

 The semiconductive perovskite-type oxide SrFeO_3-x (x<0.16) (SFO) thin films have been directly fabricated on (001)SrTiO₃ and (001)LaAlO₃ single crystal substrates by pulsed laser deposition(PLD) under high oxygen partial pressure of 100 Pa. The SFO thin films were (110) oriented. The x-ray photoelectron spectroscopy (XPS) analysis showed that the surface of SFO thin film has strong gas absorption capability. The resistance versus temperature has been measured in the temperature range from 77 K to 300 K. The SFO thin film showed typical semiconductive property. Dependence of resistance of SFO thin film on oxygen pressure was measured and result showed that the SFO thin film had better oxygen sensitive property. Received: 14 May 1996/Accepted: 15 August 1996     

SiC过渡层制备温度对碳化硅/氟化类金刚石复合薄膜血液相容性的影响

以316L不锈钢为基底,SiC晶体为靶材,Ar为源气体,采用磁控溅射法在不同温度下制备出系列SiC过渡层.然后以高纯石墨作靶,Ar和CHF_3为源气体,在同一工艺条件下再续镀一层氟化类金刚石(F-DLC)薄膜,形成SiC/F-DLC复合薄膜.研究表明,相比于F-DLC薄膜,复合薄膜的附着力显著增加,血液相容性明显改善.通过样品的拉曼和红外光谱分析了不同温度下制备的SiC过渡层以及复合薄膜结构的演变.结果表明,控制SiC过渡层制备温度可以有效调制过渡层中C=C键的比例以及—C—C—不饱和键的密度,复合薄膜中保留较高比例的芳香环式结构以及合适的F/C比是薄膜的血液相容性得以进一步改善的原因,SiC过渡层制备温度控制在500℃左右效果尤为明显.SiC薄膜和F-DLC两种薄膜的界面处形成一定比例的Si—C键和C=C键是导致复合薄膜附着力显著上升的直接原因.适当条件下在316L不锈钢和F-DLC薄膜之间增加SiC过渡层对于增强薄膜的附着力、改善其血液相容性是可行、有效的.     

基片温度对磁控溅射HfO2薄膜结构和性能影响分析

在纯氧条件下,采用直流磁控溅射技术在单晶硅基片上沉积氧化铪（HfO2）薄膜,并研究了沉积过程中基片温度对薄膜结构和性能的影响规律。利用X射线衍射仪（XRD）和X射线能谱（XPS）表征了薄膜的晶体结构和组分,利用原子力显微镜（AFM）观察薄膜表面形貌,利用纳米力学测试系统表征了薄膜的纳米硬度和弹性模量。结果表明:磁控溅射制备的HfO2薄膜样品呈(111)择优生长,其晶粒尺寸随着基片温度的升高而增大,但其晶型并不发生转变。随着基片温度的增加,基片中的硅元素向薄膜内扩散,影响了薄膜的化学计量比。沉积薄膜的表面形貌和力学性能亦受到其结构和组分变化的影响。在200 ℃条件下制备的HfO2薄膜纯度高,O、Hf元素化学计量达到了1.99,其表面质量和力学性能均达到了最佳值,随着基片温度升高至300 ℃以上,薄膜纯度下降,表面质量和力学性能均产生劣化。     

Oxidation behaviour of SiC coatings

Amorphous silicon carbide (SiC) films were deposited on silicon substrates by radio-frequency magnetron sputtering. The films were oxidized in air in the temperature range 400–900 °C and for times from 1 to 16 h. Neutron reflectivity measurements provided information on the thickness, density and roughness of the SiC and on the formed SiO₂ layers. Fourier transform infrared spectroscopy was used to determine the bond structure of the formed SiO₂ and changes in the bonding of SiC after exposure at the oxidation temperature. The surface morphology of the oxidized films was characterized by atomic force microscopy measurements. The oxidation kinetics is initially fast and as the SiO₂ layer is formed it slows down. The SiC consumption varies linearly with time at all oxidation temperatures. Exposure of the SiC at the oxidation temperature affects its density and to some degree its bond structure, while the formed SiO₂ has density and bond structure as that formed by oxidation of Si under the same conditions. PACS  66.30.Ny; 68.47.Gh; 68.55.J-     

聚丙烯孔洞驻极体膜的化学表面处理及电荷稳定性

利用热刺激放电(Thermally Stimulated Discharge, TSD)电流谱、在线电荷TSD、电荷等温衰减测量和衰减全反射(Attenuated Total Reflection, ATR)红外光谱分析，本文系统地研究了经化学表面处理(萃取、氧化及氢氟酸)的聚丙烯(PP)孔洞驻极体膜的电荷储存稳定性及电荷稳定性提高的原因.结果表明：经适当地氧化和氢氟酸室温处理试样的TSD电流谱中在温位约为184℃处出现原膜所没有的非常强的新峰，电荷热稳定性得到显著的提高，这一电荷热稳定性通过高温充电工艺得到进一步地改善；适当延长室温下氢氟酸处理的时间或延长氧化时间，都会使处理膜的电荷稳定性得到提高.理论分析表明在线电荷TSD测量法可给出线性升温过程中电荷重心及驻极体电荷量变化的综合信息，结合TSD电流谱和初始电荷重心位置的测量，可精确地考察线性升温过程中电荷重心的在线变化. 关键词： 聚丙烯孔洞膜 表面氧化 氢氟酸处理 电荷稳定性 在线电荷TSD     

ZnO/Zn界面对纳米ZnO薄膜光学性质的影响

采用氧等离子体辅助电子束蒸发金属Zn后低温退火的方法制备纳米ZnO薄膜。利用X射线衍射(XRD)谱、拉曼(Raman)谱、X射线光电子能谱(XPS)以及光致发光(PL)谱等手段,分析了退火温度及ZnO/Zn界面对样品的结构和发光性质的影响。Raman结果表明随着退火温度的升高,界面模式(Es)振动减弱并向低波数方向移动。当退火温度为400℃时,界面振动消失,Zn全部转化成具有六方纤锌矿结构的ZnO,得到化学配比的纳米ZnO薄膜。PL谱表明,经400℃退火处理的样品紫外发射最强,发光性质最好。     

Thermal oxidation temperature dependence of 4H-SiC MOS interface

The thermal oxidation temperature dependence of 4H-silicon carbide (SiC) is systematically investigated using X-ray photoelectron spectroscopy (XPS) and capacitance-voltage (C-V) measurements. When SiC is thermally oxidized, silicon oxycarbides (SiC_xO_y) are first grown and then silicon dioxide (SiO₂) is grown. It is identified by XPS that the SiO₂ films fall into two categories, called SiC-oxidized SiO₂ and Si-oxidized SiO₂ in this paper. The products depend on thermal oxidation temperature. The critical temperature is between 1200 and 1300 °C. The interface trap density (D_it) of the sample possessing Si-oxidized SiO₂, at thermal oxidation temperature of 1300 °C, is lower than SiC-oxidized SiO₂ at and below 1200 °C, suggesting that a decrease of the C component in SiO₂ film and SiO₂/SiC interface by higher oxidation temperature improves the metal-oxide-semiconductor (MOS) characteristics.     

Growth Kinetics of Silicon Carbide Film Prepared by HeatingPolystyrene/Si(111)

在不同的温度下热处理用sol-gel法制的PS/Si(111)叠层凝胶膜制备出了SiC薄膜．用XRD、SEM、XPS、FTIR等分析方法研究了SiC薄膜的结构、组成和表面形貌等．根据FTIR光谱计算了不同温度下得到的SiC薄膜的厚度,并研究了PS/Si(111)热解法生长SiC薄膜的生长动力学．结果表明,随着生长温度的增加,SiC薄膜生长速率变化趋势为：1200～1250 oC生长速率增加缓慢是2D生长机制,1250～1270 oC生长速率快速增加是3D生长机制,1270～1300 oC生长速率为负增长是由于SiC薄膜生长与Si和C原子的挥发共同作用所致．由速率变化求得各段表观生长激活能分别是122.5、522.5、-127.5 J/mol．     

乙醇对纳米多孔氧化铝薄膜光致发光特性的影响

采用二次阳极氧化法,用乙醇与草酸的混合溶液制备纳米多孔氧化铝薄膜。扫描电子微镜结果显示,乙醇与草酸混合溶液中制备的氧化铝薄膜形貌更规整,有序度更高。光致发光测试结果表明,该混合电解液制备的薄膜的光致发光强度有明显的提高,且随乙醇浓度的增加,发光强度逐渐增大。结合红外反射光谱及X光电子能谱对上述实验现象进行了分析,为多孔氧化铝薄膜掺杂和改善其发光特性提供了新的思路。     

铝诱导层交换超薄多晶硅薄膜制备及压阻特性

超薄多晶硅薄膜具有优异的压敏特性。铝诱导层交换(ALILE)制备多晶硅薄膜具有成膜温度低薄膜性能优良等特点。利用ALILE方法在玻璃基底上低温条件下制备了50 nm超薄多晶硅(poly-Si)薄膜,并对薄膜微观结构及压阻特性进行了研究。Raman光谱在521 cm-1出现尖锐、对称的特征峰,表明超薄多晶硅薄膜晶化状态良好。此外,在拉曼光谱480 cm-1处没有明显出现a-Si的Raman特征峰也说明制备的poly-Si薄膜样品完全结晶;XRD光谱表明ALILE制备薄膜在(111)和(220)晶向择优生长,晶粒尺寸约5 μm;霍尔效应测试结果表明：ALILE制备薄膜为p型掺杂,空穴浓度为9×1018～6×1019 cm-3;压阻特性研究表明：ALILE超薄多晶硅薄膜应变系数(GF)达到了60以上,且与薄膜厚度相关;应变温度相关系数(TCGF)在-0.17～0%℃范围内;电阻温度相关系数(TCR)在-0.2～-0.1%℃范围内。ALILE超薄多晶硅薄膜具有GF大、TCGF小和TCR小等特点。因此,有望在压力传感器领域得到应用。     

Zn/O ratio and oxygen chemical state of nanocrystalline ZnO films grown at different temperatures

ZnO nanocrystalline films are prepared on Si substrates at different temperatures by using metal-organic chemical vapour deposition (MOCVD). It is observed that when the growth temperature is low, the stoichiometric ratio between Zn and O atoms has a large deviation from the ideal ratio of 1:1. The ZnO grains in the film have small sizes and are not well crystallized, resulting in a poor photoluminescence (PL) property. When the temperature is increased to an appropriate value, the Zn/O ratio becomes optimized, and most of Zn and O atoms are combined into Zn-O bonds. Then the film has good crystal quality and good PL property. If the temperature is fairly high, the interfacial mutual diffusion of atoms between the substrate and the epitaxial film appears, and the desorption process of the oxygen atoms is enhanced. However, it has no effect on the film property. The film still has the best crystal quality and PL property.     

Zn/O ratio and oxygen chemical state of nanocrystalline ZnO films grown at different temperatures

ZnO nanocrystalline films are prepared on Si substrates at different temperatures by using metal-organic chemical vapour deposition(MOCVD).It is observed that when the growth temperature is low,the stoichiometric ratio between Zn and O atoms has a large deviation from the ideal ratio of 1:1.The ZnO grains in the film have small sizes and are not well crystallized,resulting in a poor photoluminescence(PL) property.When the temperature is increased to an appropriate value,the Zn/O ratio becomes optimized,and most of Zn and O atoms are combined into Zn-O bonds.Then the film has good crystal quality and good PL property.If the temperature is fairly high,the interfacial mutual diffusion of atoms between the substrate and the epitaxial film appears,and the desorption process of the oxygen atoms is enhanced.However,it has no effect on the film property.The film still has the best crystal quality and PL property.     

Effects of rapid thermal annealing on the morphology and optical properity of ultrathin InSb film deposited on SiO2/Si substrate

Ultrathin InSb thin films on SiO₂/Si substrates are prepared by radio frequency (RF) magnetron sputtering and rapid thermal annealing (RTA) at 300, 400, and 500℃, respectively. X-ray diffraction (XRD) indicates that InSb film treated by RTA at 500℃, which is higher than its melting temperature (about 485℃), shows a monocrystalline-like feature. High-resolution transmission electron microscopy (HRTEM) micrograph shows that melt recrystallization of InSb film on SiO₂/Si(111) substrate is along the (111) planes. The transmittances of InSb films decrease and the optical band gaps redshift from 0.24 eV to 0.19 eV with annealing temperature increasing from 300℃ to 500℃, which is indicated by Fourier transform infrared spectroscopy (FTIR) measurement. The observed changes demonstrate that RAT is a viable technique for improving characteristics of InSb films, especially the melt-recrystallized film treated by RTA at 500℃.