Polarity control of GaN epilayers grown on ZnO templates

We report the successful growth of Ga-polar GaN epilayers on O-polar ZnO templates pre-deposited on c-sapphire. Prior to GaN growth, NH₃ is exposed onto the ZnO template. The polarity of the GaN layers is confirmed by etching of the surface and by conversion beam electron diffraction (CBED), while the O-polar ZnO is confirmed by CBED. It is suggested that the NH₃ pre-exposure helps form a Zn₃N₂ layer, which possesses inversion symmetry and inverts the crystal from anion polar to cation polar.     

加固改造中的结构承重体系转换

从加固改造工程的实践出发 ,探讨了混合结构向框架结构体系转换的方法和构造措施 ,为实际工程提供了新的技术思路     

预应力钢-混凝土组合梁的应用与研究

回顾了预应力钢 混凝土组合梁国内外应用与研究历史 ,分析了现有规范及理论的不足 ,并指出了有待解决的问题。     

Pyrolysis of tertiarybutylphosphine at low pressure

The pyrolysis of tertiarybutylphosphine (TBP) has been studied in the low pressure conditions used for chemical beam epitaxy (CBE). The pyrolysis studies were carried out in low pressure reactors of two different configurations, one of which is a cracker cell designed for use in a CBE system. The reaction products were studied using a quadrupole mass spectrometer. The products observed are accounted for by a reaction mechanism involving homolysis of the parent TBP molecule to produce PH₂ and C₄H₉ radicals. These undergo subsequent reactions to form the stable products C₄H₈, PH₃ and H₂, with smaller amounts of P and P₂ being produced. The production of the sub-hydride PH₂ using this cracker cell design indicates that the use of partially cracked TBP may be a promising technique for reducing the amount of carbon incorporated into the growing epitaxial layer.     

步进式加热炉炉温优化设定模型及软件开发

针对线材厂步进式加热炉实际工况，提出了基于经验规则的炉温优化设定模型和在线自学习获取知识的思想，并以炉温优化设定模型为核心，开发出加热炉计算机控制系统的优化运行软件。     

循环流液相等电聚焦方法及应用研究

利用循环流液相等电聚焦技术，对Ｈｂ、Ｃｙｔ．Ｃ和ＢＳＡ混合物进行分离，对ＲＮａｓｅＡ粗制品进行精制。该方法上样量大，活性回收好。对聚焦过程中扩散、对流和电渗的影响进行了讨论。     

国际微电子专用关键设备的现状和发展趋势（考察报告）

讲述了参观Ｓｅｍｉｃｏｎ／ｗｅｓｔ９４′展览会及考察美国和西德的５个公司、１所大学所了解到的投影光刻技术、电子束曝光技术、透镜面形测试技术的发展。     

锁相技术在电子束曝光机工件台稳速控制中的应用

采用锁相技术，对电子束曝光机工件台运动实现速度环的全数字控制。设计了数字差频积分回路和数字差频比例控制器，能有效消除速度的静态误差和改善系统的动态特性。     

Selective area epitaxy of CdTe

We have performed selective area epitaxy (SAE) of CdTe layers grown by molecular beam epitaxy using a shadow mask technique. This technique was chosen over other SAE techniques due to its simplicity and its compatibility with multiple SAE patterning steps. Features as small as 50 microns × 50 microns were obtained with sharp, abrupt side walls and flat mesa tops. Separations between mesas as small as 20 microns were also obtained. Shadowing effects due to the finite thickness of the mask were reduced by placing the CdTe source in a near normal incidence position. Intimate contact between the mask and the substrate was essential in order to achieve good pattern definition.