An early in-situ stress signature of the AlN-Si pre-growth interface for successful integration of nitrides with (111) Si

The integration of Metal Organic Chemical Vapor Deposition (MOCVD) grown group III-A nitride device stacks on Si (111) substrates is critically dependent on the quality of the first AlN buffer layer grown. A Si surface that is both oxide-free and smooth is a primary requirement for nucleating such layers. A single parameter, the AlN layer growth stress, is shown to be an early (within 50 nm), clear (<0.5 GPa versus > 1GPa), and fail-safe indicator of the pre-growth surface, and the AlN quality required for successful epitaxy. Grain coalescence model for stress generation is used to correlate growth stress, the AlN-Si interface, and crystal quality. (C) 2013 AIP Publishing LLC.

(111)Si上外延生长六方GaN的TEM观察

利用衍衬、SAED、HRTEM对在（111）Si上外延生长的六方GaN进行了观察分析。GaN外延层与缓冲层和基底的取向关系为(0001)_(GaN)∥(0001)_(AlN)∥(111)_(Si)，[11(2-bar)0]_(GaN)∥[11(2-bar)0]_(AlN)∥[110]_(Si)。GaN外延层中存在倒反畴。GaN中位错以刃型位错为主。In_(0.1) Ga_(0.9) N/GaN的多重量子阱结构（MQW）具有阻挡穿透位错，降低位错密度的作用。

质量分离的双离子束沉积法生长CeO_2（111）/Si薄膜

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Evolution of epitaxial graphene layers on 3C SiC/Si (111) as a function of annealing temperature in UHV

The growth of graphene on SiC/Si substrates is an appealing alternative to the growth on bulk SiC for cost reduction and to better integrate the material with Si based electronic devices. In this paper, we present a complete in-situ study of the growth of epitaxial graphene on 3C SiC (111)/Si (111) substrates via high temperature annealing (ranging from 1125˚C to 1375˚C) in ultra high vacuum (UHV). The quality and number of graphene layers have been thoroughly investigated by using x-ray photoelectron spectroscopy (XPS), while the surface characterization have been studied by scanning tunnelling microscopy (STM). Ex-situ Raman spectroscopy measurements confirm our findings, which demonstrate the exponential dependence of the number of graphene layer from the annealing temperature.

Scanning transmission electron microscopy investigation of the Si(111)/AlN interface grown by metalorganic vapor phase epitaxy

The structure and chemistry of the interface between a Si(111) substrate and an AlN(0001) thin film grown by metalorganic vapor phase epitaxy have been investigated at a subnanometer scale using high-angle annular dark field imaging and electron energy-loss spectroscopy. 〈1120̄〉AlN ∥ 〈110〉Si and 〈0001〉AlN ∥ 〈111〉 Si epitaxial relations were observed and an Al-face polarity of the AlN thin film was determined. Despite the use of Al deposition on the Si surface prior to the growth, an amorphous interlayer of composition SiNx was identified at the interface. Mechanisms leading to its formation are discussed. © 2010 American Institute of Physics.

Microstructural and compositional characteristics of GaN films grown on a ZnO-buffered Si(111) wafer

Polycrystalline GaN thin films have been deposited epitaxially on a ZnO-buffered (111)-oriented Si substrate by molecular beam epitaxy. The microstructural and compositional characteristics of the films were studied by analytical transmission electron microscopy (TEM). A SiO2 amorphous layer about 3.5 nm in thickness between the Si/ZnO interface has been identified by means of spatially resolved electron energy loss spectroscopy. Cross-sectional and plan-view TEM investigations reveal (GaN/ZnO/SiO2/Si) layers exhibiting definite a crystallographic relationship: [111](Si)//[111](ZnO)//[0001](GaN) along the epitaxy direction. GaN films are polycrystalline with nanoscale grains (similar to100 nm in size) grown along [0001] direction with about 20degrees between the (1 (1) over bar 00) planes of adjacent grains. A three-dimensional growth mode for the buffer layer and the film is proposed to explain the formation of the as-grown polycrystalline GaN films and the functionality of the buffer layer. (C) 2004 Elsevier Ltd. All rights reserved.

Microstructure of GaN films grown on Si(111) substrates by metalorganic chemical vapor deposition

We report the transmission electron microscopy (TEM) study of the microstructure of wurtzitic GaN films grown on Si(I I I) substrates with AlN buffer layers by metalorganic chemical vapor deposition (MOCVD) method. An amorphous layer was formed at the interface between Si and AlN when thick GaN film was grown. We propose the amorphous layer was induced by the large stress at the interface when thick GaN was grown. The In0.1Ga0.9N/GaN multiple quantum well (MQW) reduced the dislocation density by obstructing the mixed and screw dislocations from passing through the MQW. But no evident reduction of the edge dislocations by the MQW was observed. It was found that dislocations located at the boundaries of grains slightly in-plane misoriented have screw component. Inversion domain is also observed. (C) 2003 Elsevier B.V. All rights reserved.

Structural properties and Raman measurement of AlN films grown on Si (111) by NH3-GSMBE

Epitaxial growth of AlN has been performed by molecular beam epitaxy (MBE) with ammonia. The structural properties of materials were studied by cross-sectional transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM). XRD and TEM diffraction pattern confirm the AlN is single crystalline 2H-polytype with the epitaxial relationship of (0001)AlNparallel to(111)Si, [11 (2) over bar0](AlN)parallel to[110](Si), [10 (1) over bar0](AlN)parallel to[11 (2) over bar](Si). Micro-Raman scattering measurement shows that the E-2 (high) and A(1) (LO) phonon mode shift 9 cm(-1) toward the low frequency, which shows the existence of large tensile strain in the AlN films. Furthermore, the appearance of forbidden A, (TO) mode and its anomalous shift toward high frequency was found and explained. (C) 2002 Elsevier Science B.V. All rights reserved.

Microstructural and compositional characteristics of GaN films grown on a ZnO-buffered Si(111) wafer

Polycrystalline GaN thin films have been deposited epitaxially on a ZnO-buffered (111)-oriented Si substrate by molecular beam epitaxy. The microstructural and compositional characteristics of the films were studied by analytical transmission electron microscopy (TEM). A SiO2 amorphous layer about 3.5 nm in thickness between the Si/ZnO interface has been identified by means of spatially resolved electron energy loss spectroscopy. Cross-sectional and plan-view TEM investigations reveal (GaN/ZnO/SiO2/Si) layers exhibiting definite a crystallographic relationship: [111](Si)//[111](ZnO)//[0001](GaN) along the epitaxy direction. GaN films are polycrystalline with nanoscale grains (similar to100 nm in size) grown along [0001] direction with about 20degrees between the (1 (1) over bar 00) planes of adjacent grains. A three-dimensional growth mode for the buffer layer and the film is proposed to explain the formation of the as-grown polycrystalline GaN films and the functionality of the buffer layer. (C) 2004 Elsevier Ltd. All rights reserved.

Microtwins and twin inclusions in the 3C-SiC epilayers grown on Si(001) by APCVD

Microtwins in the 3C-SiC films grown on Si(001) by APCVD were analyzed in detail using an X-ray four-circle diffractometer. The empty set scan shows that 3C-SiC films can grow on Si substrates epitaxially and the epitaxial relationship is revealed as (001)(3C-SiC)//(001)(Si), [111](3C-SiC)//[111](Si). Other diffractions emerged in the pole figures of the (111) 3C-SiC. We performed the (10 (1) over bar0) h-SiC and the reciprocal space mapping of the (002) plane of twins for the first time, finding that the diffractions at chi = 15.8 degrees result from not hexagonal SiC but microtwins of 3C-SiC, and twin inclusions are estimated to be 1%.

Uniformity Investigation in 3C-SiC Epitaxial Layers Grown on Si Substrates by Horizontal Hot-Wall CVD

50mm 3C-SiC epilayers are grown on （100） and （111） Si substrates in a newly developed horizontal lowpressure hot-wall CVD reactor under different growth pressures and flow rates of H_2 carrier gas. The structure,electrical properties, and thickness uniformity of the 3C-SiC epilayers are investigated by X-ray diffraction （XRD） ,sheet resistance measurement, and spectroscopic ellipsometry. XRD patterns show that the 3C-SiC films have excellent crystallinity. The narrowest full widths at half maximum of the SIC（200） and （111） peaks are 0.41° and 0.21°, respectively. The best electrical uniformity of the 50mm 3C-SiC films obtained by sheet resistance measurement is 2.15%. A σ/mean value of ± 5.7% in thickness uniformity is obtained.

Si衬底和Si-SiO2-Si柔性衬底上的GaN生长

使用MBE方法在Si(111)衬底和Si-SiO2-Si柔性衬底上生长了GaN外延层,并对在两种衬底上生长的样品进行了对比分析.在柔性衬底上获得了无裂纹的外延层,其表面粗糙度为0.6nm.研究了GaN外延层中的应力及其光学性质,光致发光测试结果表明柔性衬底上生长的外延层中应力和杂质浓度明显低于直接生长在Si衬底上的样品的值.研究结果显示了所用柔性衬底有助于改善GaN外延膜的质量.

GaN蓝光材料新型ZnO/Si外延衬底的溅射沉积

采用常规磁控溅射方法，通过优化工艺，在Si(100),Si(111)多种基片上沉积ZnO薄膜。利用透射电镜(TEM)、X射线衍射(XRD)和X射线摇摆曲线(XRC)，对ZnO薄膜的微区形貌、结晶情况、C轴择优取向进行了详细的测试分析。结果表明，所制备的ZnO薄膜具有理想的结构特性，大多数样品测得ZnO(002)晶面XRC的半高宽(FWHM)1°左右，最小值达0.353°，优于目前国内外同类研究的最佳结果2°。并对ZnO/Si(100)与ZnO/Si(111)衬底的结果进行了比较和讨论。

硅（111）和金（111）基底自组装膜表面纳米图案化与功能化

利用导电原子力显微镜在烷基化自组膜/Si(111)和巯基自组膜/Au(111)上加工纳米模板,结合组装的方法构建功能化纳米图案。在烷基化自组膜/Si(111)上施加偏压可以得到SiO2纳米图案,此图案可以做功能化模板,将图案化区域组装胺基作为端基的硅烷后,通过1-乙基-3-（3-二甲基氨基丙基）碳二亚胺盐酸盐(EDC)/N-羟基琥珀酰亚胺(NHS)试剂活化共价结合11-巯基十一酸(MUA)稳定的金纳米粒子,得到金纳米粒子功能化纳米图案。在烷基硫醇自组装膜/Au(111)施加偏压可以选择性移除自组装膜,移除自组装膜后新暴露的金可以用做纳米模板,在此模板上组装MUA后通过EDC/NHS活化共价键合溶菌酶,得到蛋白质功能化的纳米点阵图案。