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Chinese Physics B 2024年第3期33卷 630-637页

作者：黄威俞金玲刘雨彭燕王利军梁平陈堂胜徐现刚刘峰奇陈涌海 Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China National Key Laboratory of Solid-state Microwave Devices and Circuits Nanjing Electronic Devices InstituteNanjing 210016China Institute of Micro/Nano Devices and Solar Cells School of Physics and Information EngineeringFuzhou UniversityFuzhou 350108China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)*** reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by *** RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic *** comparing with the Raman spectrum,it is verified that the micropipes consist of edge *** different patterns of the RA images are due to the different orientations of the Burgers ***,the strain distribution of the micropipes is also *** can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using ***,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.

关键词： scanning anisotropy microscopy SiC reflection anisotropy edge dislocation

Hierarchical Porous Patterns of n-type 6H-SiC Crystals via Photoelectrochemical Etching

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Journal of Materials Science & Technology 2013年第7期29卷 655-661页

作者： Lihuan Wang Huihui Shao Xiaobo Hu xiangang xu State Key Laboratory of Crystal Materials Shandong University

Hierarchical porous patterns have been fabricated on the C face, Si face, and cross section of n-type 6H-SiC crystal via photo-electrochemical etching using HF/C2H5OH and HF/H2O2 as electrolytes. The porous layer displayed multiple and multiscale microstructures on different faces, including stalactite-like, sponge-like and dendritic porous structures on C face, echinoid micro-patterns on Si face, and columnar and keel-shaped micro-patterns on the cross section. The formation of hierarchical porous pattern is ascribed to the dynamic competition balance between the electrochemical oxidation rate and the oxide removal rate. It was found that increasing the ionic strength of the electrolyte can obviously disturb the surface morphology of the porous SiC during the photo-electrochemical etching. Possible mechanisms for selective etching were further discussed.

关键词： SiC Photo-electrochemical etching Porous patterning

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大功率808 nm分布反馈激光器阵列研制

固体电子学研究与进展 2024年第1期44卷 72-76页

作者：孙春明朱振任夫洋陈康苏建夏伟徐现刚山东大学新一代半导体材料研究院济南250100 济南大学物理科学与技术学院济南250022 山东华光光电子股份有限公司济南250000

为了提高808 nm大功率半导体激光器阵列的波长稳定性,提出了带有二阶布拉格光栅的大功率宽条型808 nm分布反馈激光器阵列。相比于传统的一阶布拉格光栅,其可以显著抑制简并纵模的产生,提高器件的波长锁定范围。借助于金属有机化学气相... 详细信息

为了提高808 nm大功率半导体激光器阵列的波长稳定性,提出了带有二阶布拉格光栅的大功率宽条型808 nm分布反馈激光器阵列。相比于传统的一阶布拉格光栅,其可以显著抑制简并纵模的产生,提高器件的波长锁定范围。借助于金属有机化学气相沉积、全息光刻、干法刻蚀以及湿法腐蚀等工艺,完成了器件的制备,并且在准连续条件(200 A、200μs、20 Hz)下,对所制备的激光器阵列进行了不同温度下的性能测试。测试结果表明:器件峰值输出功率可达到190 W,光电转换效率超过55%,光谱半高宽为0.6 nm,温漂系数为0.06 nm/K,波长锁定范围达到125℃(-35~90℃)。另外,对其进行了老化考评,结果显示,老化2 000 h后峰值功率衰减小于4%。

关键词：温漂系数二次外延全息光刻二阶光栅激光器阵列

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原料颗粒度对AlN晶体生长的影响

人工晶体学报 2024年第1期53卷 58-64页

作者：俞瑞仙王国栋王守志曹文豪胡小波徐现刚张雷山东大学深圳研究院深圳518000 山东大学新一代半导体材料研究院晶体材料国家重点实验室济南250100

本文通过对氮化铝(AlN)粉末进行烧结,制备了AlN晶体生长用的多晶颗粒料,测试发现,与粉末原料相比,多晶颗粒料的杂质显著降低。利用数值模拟软件研究了不同原料孔隙率对晶体生长的影响,分析了相同晶体生长工艺条件下原料内部温场的分布... 详细信息

本文通过对氮化铝(AlN)粉末进行烧结,制备了AlN晶体生长用的多晶颗粒料,测试发现,与粉末原料相比,多晶颗粒料的杂质显著降低。利用数值模拟软件研究了不同原料孔隙率对晶体生长的影响,分析了相同晶体生长工艺条件下原料内部温场的分布情况。使用不同颗粒度的原料进行了AlN晶体生长,发现最适合AlN晶体生长的温度梯度和原料颗粒度。最后用颗粒度为1~3 mm的多晶颗粒料进行晶体生长,生长出直径为1英寸、厚度为15 mm的AlN晶体。对晶体进行切割、研磨、抛光,得到1英寸AlN晶片。采用高分辨率X射线衍射(HRXRD)和拉曼光谱对晶片进行表征。结果发现HRXRD摇摆曲线半峰全宽(FWHM)为154.66″,E_(2)(high)声子模的峰位置和FWHM分别为656.7和4.3 cm^(-1),表明该AlN晶体结晶质量良好。

关键词： AlN晶体多晶颗粒料孔隙率 VR-PVT 温场杂质

维普期刊数据库博看期刊

Effective Increase of Crystal Area during Sublimation Growth of 6H-SiC by Using the Cone-shaped Baffle

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Journal of Materials Science & Technology 2007年第5期23卷 685-688页

作者： Shouzhen JIANG xiangang xu Xiaobo HU Juan LI Xiufang CHEN Minhua JIANG State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China College of Physics and Electronics Shandong Normal University Jinan 250014 China

A novel design of crucible is proposed in this paper for the growth of SiC crystals. The relation between grown crystal shape and temperature distribution in a growth chamber was discussed. It is pointed out that the crystal shape had a close relationship with temperature distribution. The calculations suggested that the radial temperature field of the growing crystal became homogenous by setting up the cone-shaped baffle in the growth chamber. By modifying the crucible design and temperature distribution in the growth chamber, it is possible to enhance the enlargement of crystal, and also possible to keep grown surface flat.

关键词： 6H-SIC Sublimation method Simulation Temperature distribution

Fine Machining of Large-Diameter 6H-SiC Wafers

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Journal of Materials Science & Technology 2006年第5期22卷 681-684页

作者： Xiufang CHEN Juan LI Deying MA Xiaobo HU xiangang xu Minhua JIANG State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

Three main machining processes of large-diameter 6H-SiC wafers were introduced in this paper. These processes include cutting, lapping and polishing. Lapping causes great residual stresses and deep damage layer which can be reduced gradually with subsequent polishing processes. Surfaces prepared by mechanical polishing （MP） appeared a large number of scratches with depth of 5-8 nm. These scratches can be effectively removed by chemo-mechanical polishing （CMP）. After CMP. extremely smooth and low damage layer surface with roughness Ra=0.3 nm was obtained. Atomic force microscopy （AFM） and optical microscopy were used to observe the surface morphology of samples and a high resolution X-ray diffractometer （HRXRD） was used for the crystal lattice perfection of the subsurface region. Changes of surface residual stresses during machining processes were investigated by HRXRD.

关键词： 6H-SiC Chemo-mechanical polishing (CMP) Roughness

Synthesis of High Purity SiC Powder for High-resistivity SiC Single Crystals Growth

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Journal of Materials Science & Technology 2007年第1期23卷 118-122页

作者： Li WANG Xiaobu HU xiangang xu Shouzheng JIANG Lina NING Minhua JIANG State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.

关键词： Activated carbon Flaky graphite Particle size SiC powder High purity

Investigation of the 6H-SiC (0001) surface by AFM

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Journal of University of Science and Technology Beijing 2008年第5期15卷 654-658页

作者： Shouzhen Jiang Guangwei Yu Yingmin Wang Xiaobo Hu xiangang xu Minhua Jiang State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China College of Physics and Electronics Shandong Normal University Jinan 250014 China

Micropipe and step structures on 6H-SiC （0001） surface were investigated by an atomic force microscopy （AFM）. On the facet,all micropipes examined are the origins of spiral steps,indicating that dislocations intersect the surface at these points. Micropipes are empty-core super-dislocations as originally described by Frank. The micropipe radius increases with the square of the dislocation Burgers vector. From the center to the periphery,step structures change with different surface inclinations. Regular step is observed within the central faceted area. Step bunching and atomically rough surfaces are observed within the peripheral convex area. If the inclination with respect to the （0001） plane is large enough,step bunching of 15R-SiC can be observed.

关键词： atomic force microscopy micropipes step bunching polytypes

Thermal Oxidation of Silicon Carbide Substrates

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Journal of Materials Science & Technology 2009年第1期25卷 115-118页

作者： Xiufang Chen Liana Ning Yingmin Wang Juan Li xiangang xu Xiaobo Hu Minhua Jiang State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

Thermal oxidation was used to remove the subsurface damage of silicon carbide （SIC） surfaces. The anisotropy of oxidation and the composition of oxide layers on Si and C faces were analyzed. Regular pits were observed on the surface after the removal of the oxide layers, which were detrimental to the growth of high quality epitaxial layers. The thickness and composition of the oxide layers were characterized by Rutherford backscattering spectrometry （RBS） and X-ray photoelectron spectroscopy （XPS）, respectively. Epitaxial growth was performed in a metal organic chemical vapor deposition （MOCVD） system. The substrate surface morphology after removing the oxide layer and gallium nitride （GaN） epilayer surface were observed by atomic force microscopy （AFM）. The results showed that the GaN epilayer grown on the oxidized substrates was superior to that on the unoxidized substrates.

关键词： SiC Thermal oxidation GaN epitaxy

Using coupling slabs to tailor surface-acoustic-wave band structures in phononic crystals consisting of pillars attached to elastic substrates

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Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 45-50页

作者： Heng Zhang SiYuan Yu FuKang Liu Zhen Wang MingHui Lu XiaoBo Hu YanFeng Chen xiangang xu State Key Laboratory of Crystal Materials Shandong University National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering Nanjing University

The propagation of surface acoustic waves(SAWs) in two-dimensional phononic crystals(PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element *** piezoelectric substrates,for example,lithium niobate(LiNbO_3),gallium nitride(GaN),and aluminium nitride(A1N),were taken into *** to the PnCs without coupling-enhancement slabs,the coupling between each pillar and its nearest neighbor was largely enhanced in the presence of *** bandwidth of the first directional band gap increased markedly compared with its initial value for the PnCs without a slab(within square symmetry).In addition,with increasing thicknesses of the slabs bonded between neighboring pillars,the first directional band-gap and second directional band gap of the PnCs tend to ***,the structure with coupling-enhancement slabs can be used as an excellent electrical band elimination filter for most electro-SAW devices,offering a new strategy to realize chip-scale applications in electroacoustic signal processing,optoacoustic modulation,and even SAW microfluidic devices.

关键词： surface acoustic waves(SAWs) phononic crystals(PnCs) tailored band structure