低能碳离子束沉积(111)织构的立方SiC薄膜

在硅衬底上利用具有质量选择功能的低能离子束沉积技术沉积碳离子制备出除碳、硅之外无其他杂质元素的纯净的立方SiC薄膜.利用X射线光电子谱、俄歇电子能谱、X射线衍射对样品进行了表征.结果显示常温和400℃制备的样品为非晶结构,在800℃制备的样品由一富碳的表面层和有着良好化学计量比的SiC层组成,碳化硅晶体薄膜是(111)织构的.通过分析可知衬底温度、离子沉积能量和样品保温扩散时间等因素综合在一起对于在硅上沉积SiC薄膜起着重要作用.远远大于TRIM预测厚度的SiC薄膜的获得是高的衬底温度、一定注入能量的碳离子引起的增强扩散以及通道注入效应综合作用的结果.     

纳米6H-SiC薄膜的等离子体化学气相沉积及其紫外发光

采用螺旋波等离子体化学气相沉积技术在Si(100)衬底上制备了具有纳米结构的碳化硅(SiC)薄膜.通过X射线衍射、傅里叶红外吸收和扫描电子显微镜等技术对所制备薄膜的结构、形貌以及键合特性进行了分析,利用光致发光技术研究了样品的发光特性.分析表明,在500℃的衬底温度和高氢气稀释条件下,所制备的纳米SiC薄膜红外吸收谱主要表现为SiC TO声子吸收,X射线衍射显示所制备的纳米SiC薄膜为6H结构.采用氙灯作为激发光源,不同氢气流量下所制备的样品在室温下呈现出峰值波长可变的紫外发光.     

纳米6H-SiC薄膜的等离子体化学气相沉积及其紫外发光

采用螺旋波等离子体化学气相沉积技术在Si(100)衬底上制备了具有纳米结构的碳化硅(SiC)薄膜.通过X射线衍射、傅里叶红外吸收和扫描电子显微镜等技术对所制备薄膜的结构、形貌以及键合特性进行了分析,利用光致发光技术研究了样品的发光特性.分析表明,在500℃的衬底温度和高氢气稀释条件下,所制备的纳米SiC薄膜红外吸收谱主要表现为SiC TO声子吸收,X射线衍射显示所制备的纳米SiC薄膜为6H结构.采用氙灯作为激发光源,不同氢气流量下所制备的样品在室温下呈现出峰值波长可变的紫外发光.     

离子束能量和衬底温度对氧化钆结构的影响

利用双离子束沉积技术,在Si(100)衬底上制备了氧化钆薄膜.离子束能量在100～500eV范围内,衬底温度较低时薄膜为(402)择优取向的单斜结构,随着衬底温度的增加,择优取向转为(202)方向.当衬底温度是700℃时,出现了立方结构,这是由于离子束加热的作用,导致低温下出现单斜结构.XPS研究表明薄膜中存在氧缺陷,改进工艺条件可消除部分缺陷.     

离子束能量和衬底温度对氧化钆结构的影响

利用双离子束沉积技术，在Si(100)衬底上制备了氧化钆薄膜. 离子束能量在100～500eV范围内，衬底温度较低时薄膜为(402)择优取向的单斜结构，随着衬底温度的增加，择优取向转为(202)方向. 当衬底温度是700℃时，出现了立方结构，这是由于离子束加热的作用，导致低温下出现单斜结构. XPS研究表明薄膜中存在氧缺陷，改进工艺条件可消除部分缺陷.     

离子束能量和衬底温度对氧化钆结构的影响

利用双离子束沉积技术,在Si(100)衬底上制备了氧化钆薄膜.离子束能量在100～500eV范围内,衬底温度较低时薄膜为(402)择优取向的单斜结构,随着衬底温度的增加,择优取向转为(202)方向.当衬底温度是700℃时,出现了立方结构,这是由于离子束加热的作用,导致低温下出现单斜结构.XPS研究表明薄膜中存在氧缺陷,改进工艺条件可消除部分缺陷.     

离子束增强沉积法制备二氧化铪薄膜

利用离子束增强沉积(IBED)技术在硅衬底上沉积得到50nm的二氧化铪薄膜.卢瑟福背散射(RBS)的结果指出样品表面有过量氧元素存在.X射线光电子能谱(XPS)显示退火前后薄膜内部化学键没有变化.透射电子显微镜(TEM)表明界面处有非晶铪氧硅化合物生成.电子衍射(ED)显示所制备的二氧化铪薄膜呈现长程无序、区域有序的多晶态.实验为HfO2作为高k电介质在集成电路制造中的应用提供了一种简单有效的方法.     

持效疏水二氧化硅增透膜的制备和研究

为了制备结晶质量好的Cu掺杂ZnO薄膜,研究其结构和光学性质,采用脉冲激光沉积方法,在Si衬底上选择不同的衬底温度来制备薄膜.实验成功制得了结晶质量较好的Cu掺杂ZnO薄膜.利用X射线衍射仪、扫描电子显微镜和荧光分光光度计对样品进行了测量和分析.所制备的样品均表现出高度的c轴择优取向,衬底温度为300℃时,薄膜表面形貌均匀致密;在样品的光致发光谱中,发现样品除了在380nm附近出现紫外发光峰外,在460nm附近出现了蓝光发光峰,真正意义上实现了ZnO薄膜的蓝光发射.结果表明,衬底温度对其晶体质量有较大影响.     

Cu掺杂ZnO薄膜光学性质的研究

为了制备结晶质量好的Cu掺杂ZnO薄膜,研究其结构和光学性质,采用脉冲激光沉积方法,在Si衬底上选择不同的衬底温度来制备薄膜。实验成功制得了结晶质量较好的Cu掺杂ZnO薄膜。利用X射线衍射仪、扫描电子显微镜和荧光分光光度计对样品进行了测量和分析。所制备的样品均表现出高度的c轴择优取向,衬底温度为300℃时,薄膜表面形貌均匀致密;在样品的光致发光谱中,发现样品除了在380nm附近出现紫外发光峰外,在460nm附近出现了蓝光发光峰,真正意义上实现了ZnO薄膜的蓝光发射。结果表明,衬底温度对其晶体质量有较大影响。     

衬底温度对射频磁控溅射制备氮化硅薄膜的影响

采用射频磁控反应溅射技术,以N2和Ar为反应气体在普通玻璃表面沉积了氮化硅(SiN)薄膜;利用X射线衍射仪、扫描电子显微镜、X射线能量耗散谱、台阶仪和紫外-可见光谱,研究了不同衬底温度对SiN薄膜的相结构、表面形貌和成分、薄膜厚度以及光性能的影响.结果表明;制备的SiN薄膜为富硅结构;提高衬底温度,可增加光学带隙;当衬底温度为450℃时,薄膜由尺寸约为40 nm的SiN晶粒组成,且在紫外-可见光区的透过率高达90%.     

(111)晶向碲锌镉晶片双面腐蚀的对比

通过对材料减薄，并采用红外透射显微镜观察的手段，实现了对A面和B面腐蚀坑的同时观察.结果发现采用标准腐蚀剂在同一晶片的（111) A和（111) B面上形成的腐蚀坑大都不存在对应关系，深度腐蚀的实验也发现，表面腐蚀坑所对应的缺陷只局限于10μm的表层内，这表明大部分腐蚀坑所对应的不是通常认为的穿越位错. 进一步分析的结果表明，不同腐蚀剂形成的腐蚀坑所对应的缺陷有可能是不同类型的位错，甚至也可能起源于微沉淀物，通常将碲锌镉材料的腐蚀坑所对应的缺陷简单地归结为材料的位错是缺乏实验依据的.     

(111)晶向碲锌镉晶片双面腐蚀的对比

通过对材料减薄,并采用红外透射显微镜观察的手段,实现了对A面和B面腐蚀坑的同时观察.结果发现采用标准腐蚀剂在同一晶片的(111)A和(111)B面上形成的腐蚀坑大都不存在对应关系,深度腐蚀的实验也发现,表面腐蚀坑所对应的缺陷只局限于10μm的表层内,这表明大部分腐蚀坑所对应的不是通常认为的穿越位错.进一步分析的结果表明,不同腐蚀剂形成的腐蚀坑所对应的缺陷有可能是不同类型的位错,甚至也可能起源于微沉淀物,通常将碲锌镉材料的腐蚀坑所对应的缺陷简单地归结为材料的位错是缺乏实验依据的.     

Electronic Structure of SiN Layers on Si(111) and SiC/Si(111) Substrates

Semiconductors - Ultrathin epitaxial silicon nitride films were formed on different Si(111) and SiC/Si(111) substrates by nitridation with plasma-activated nitrogen. Photoemission studies of the...     

Helium-Plasma-Prepared (111)A HgCdTe and (211)B InSb

Brief low-energy helium plasma exposure of mercury cadmium telluride and indium antimonide results in oxide- and elemental-component-free, nearly stoichiometric surfaces. In these initial experiments, the only remaining residue is a topmost trace layer of carbon similar to that present on wet etched and reduced surfaces. The nature of these surfaces was determined by in situ Auger electron spectroscopy, monochromatic X-ray photoelectron, and ion scattering spectroscopy, and compared with established wet chemical and hydrogen argon plasma preparations.     

Characterization of (111) Gaas and (111) InP substrates and homoepitaxial layers by divergent x-ray beam diffraction

The back-reflection diffraction of a divergent x-ray beam has been studied for the characterization of (111) GaAs and (111) InP substrates and homoepitaxial layers with different states of surface perfection. Diffraction conditions for generating back-reflection pseudo-Kossel patterns from (111) GaAs and (111) InP are presented. Mechanical polishing was observed to produce x-ray diffraction line broadening. Uneven line broadening was found to be produced by an inhomogeneous distribution of dislocations. The diffraction angles for pseudo-Kossel lines were influenced by subgrain tilting in epitaxial, LPE-grown layers. A close relationship between diffraction line profiles and surface morphology of the epitaxial layer was demonstrated with interference-contrast optical microscopy.     

Surface structure of (111)A HgCdTe

The surface of (111)A HgCdTe has been studied by reflection high-energy electron diffraction and atomic force microscopy (AFM). The as-grown liquid-phase epitaxy (LPE) surface has bilayer (3.7 ± 0.2 Å) step/terrace structures, macro-steps, and cross-hatch patterns. Macro-steps occur about the $[11\bar 2]$ and are from 10–40 Å in height. AFM and x-ray measurements indicate the as-grown epilayer is ≈0.2° off-cut (random polar angle) from the (111). 〈110〉 cross-hatch lines consistent with bilayer (step height=3.9 ± 0.2 Å) {111} slip dislocation are observed. The native oxide/carbon layer for the as-grown LPE (111)A HgCdTe is ≈8 Å. The experimental results suggest that the as-grown LPE surface approximates an equilibrium vicinal crystal structure. The 0.1% Br:ethylene glycol wet chemically etched surfaces retained the macro-step structure, but numerous small protrusions (10–100 Å height, ≈300 Å diameter) developed. The plasma-etched (111)A HgCdTe surface is crystalline, but exhibits surface disorder and is roughened.     

Si(111)表面电子结构

本文利用自洽LMTO-ASA方法研究了晶体Si及Si(111)表面的几种模型的电子结构,给出了在slab模型各不同结构下的态密度和分波态密度,以及各不等价原子态密度和分波态密度,该结果与其它理论计算和实验结果相吻合     

Miniband spectra of (AlAs)M(GaAs)N(111) superlattices

Semiconductors - Electron states in the conduction band of (111)-oriented (AlAs)M(GaAs)N superlattices (SLs) with M≥N and N&;lt;10 are considered. The properties of such SLs are mainly...     

Raman scattering in (111) strained heterostructures

III–V based strained heterostructures grown along [hhk] directions are considered. The proportionality coefficients between the in-plane strain and the shift in the TO and LO phonon frequencies have been calculated from the elastic constants and phonon deformation potentials. GaAs/GaP (111) and GaAs/InP (111) systems, where the GaAs epitaxial layers are in compressive or tensile strain, respectively, have been grown by MOVPE at different times on A and B substrates and investigated by Raman scattering. The corresponding red or blue shifts of the frequencies of the LO and TO phonons are measured and the residual strain parallel to the interface is estimated. The Raman results are discussed on the basis of the morphology of the epilayer investigated by atomic force microscopy.