ECR-PEMOCVD技术生长的GaMnN薄膜的特性

利用电子回旋共振-等离子体增强金属有机物化学气相沉积(ECR-PEMOCVD)技术,在蓝宝石(α-Al2O3)衬底上生长出具有一定Mn含量的GaMnN稀磁半导体薄膜.RHEED图像呈现清晰的斑点状点阵,表明薄膜为单晶,表面不是很平整,为三维岛状生长模式.X射线衍射分析表明薄膜为六方结构,沿c轴方向生长,结晶性良好.AFM显示薄膜是由许多亚微米量级的晶粒按一致的取向规则堆砌而成的.超导量子干涉仪(SQUID)测量显示在室温下薄膜依然具有铁磁性,居里温度约为400K.     

基于802.11a标准的CMOS正交调制器和上变频器

采用0.18μm CMOS工艺,设计并实现了应用于WLAN IEEE 802.11a的正交调制器和上变频器.正交调制器在传统的Gilbert单元基础上,采用负反馈跨导放大器来提高线性度;上变频器采用LC谐振网络作混频器负载来提高增益和电压输出摆幅.测试结果表明,在1.8V电源电压下,谐振频率点的1dB压缩点P1dB为-3.6dBm,功率转换增益为-3.6dB,电流消耗大约45.8mA.     

Dielectric films for Si solar cell applications

Thin films of many dielectric materials have been used in the past for fabrication of solar cells and as a part of their device structure. However, current efforts to reduce solar cell costs in commercial production have led to simplification of cell design and fabrication. Use of self-aligning techniques has obviated the need for photolithography and conventional masking with dielectric films for cell fabrication. Currently, the most favored dielectric material in Si solar cell production is SiN:H, deposited by the plasma-enhanced chemical vapor deposition (PECVD) process. The SiN:H layer and its processing play multiple roles of serving as an antireflection coating, a surface passivating layer, a buffer layer through which metal is fired, and a means of transporting hydrogen into the bulk of the solar cell. In order to optimize the solar cell performance, the SiN:H layer must meet some conflicting demands. The various applications of the SiN:H layer in solar cell fabrication are described here.     

ZnS/CuInS2/Mo/钠钙玻璃衬底上射频溅射ZnO∶Al薄膜的SEM研究

结合ZnO薄膜在Cu-III-VI2基薄膜太阳电池上的应用，采用射频磁控溅射技术以陶瓷ZnO∶Al2O3为靶材在ZnS/CuInS2/Mo/钠钙玻璃衬底上于固定沉积条件下低温（200℃）制备了铝掺杂氧化锌（ZnO∶Al）薄膜. 运用扫描电子显微镜研究了底层材料特别是ZnS和CuInS2的生长参数对沉积的ZnO∶Al薄膜的表面形貌的影响. 实验发现，衬底材料中硫含量的增加（无论来自ZnS还是来自CuInS2) ，都会引起沉积ZnO∶Al薄膜结晶质量的提高，而金属含量的增大将有利于薄膜均匀性的改进.     

SIMOX埋氧层的总剂量辐射硬度对埋氧层中注氮剂量的敏感性

为了提高SIMOX(separation-by-implanted-oxygen)SOI(silicon-on-insulator)结构中埋氧层(BOX)的总剂量辐射硬度,埋氧层中分别注入了2×1015和3×1015cm-2剂量的氮.实验结果表明,在使用Co-60源对埋氧层进行较低总剂量的辐照时,埋氧层的总剂量辐射硬度对注氮剂量是非常敏感的.尽管埋氧层中注氮剂量的差别很小,但经5×104 rad(Si)剂量的辐照后,注入2×1015cm-2剂量氮的埋氧层表现出了比未注氮埋氧层高得多的辐射硬度,而注入3×1015cm-2剂量氮的埋氧层的辐射硬度却比未注氮埋氧层的辐射硬度还低.然而,随辐照剂量的增加(从5×104到5×105rad(Si)),这种埋氧层的总剂量辐射硬度对注氮剂量的敏感性降低了.采用去掉SOI顶硅层的MOS高频C-V技术来表征埋氧层的总剂量辐射硬度.另外,观察到了MSOS(metal-silicon-BOX-silicon)结构的异常高频C-V曲线,并对其进行了解释.     

A novel compact circuit for 4-PAM energy-efficient high speed interconnect data transmission and reception

Transmission of signals, whether on-chip or off-chip, places severe constraints on timing and extracts a large price in energy. New silicon device technologies, such as back-plane CMOS, provide a programmable and adaptable threshold voltage as an additional tool that can be used for low power design. We show that one particularly desirable use of this freedom is energy-efficient high-speed transmission across long interconnects using multi-valued encoding. Our multi-valued CMOS circuits take advantage of the threshold voltage control of the transistors, by using the signal-voltage-to-threshold-voltage span, in order to make area-efficient implementations of 4-PAM (pulse amplitude modulation) transceivers operating at high speed. In a comparison of a variety of published technologies, for signal transmission with interconnects of 10-15 mm length, we show up to 50% improvement in energy for on-chip signal transmission over binary encoding together with higher limits for operating speeds without a penalty in circuit noise margin.     

适合于矿井提升的Vacon变频器

本文详细介绍了Vacon变频器在矿井中的应用，该应用方案中Vacon变频器作为特殊的低频电源。Vacon变频器具有可编程功能，编程工具Vacon NC1131-3 Engineerign是一个符合IEC61131-3标准的图形化的编程工具，它可以用来设计Vacon NX特殊的控制逻辑的参数。它包含了基本功能模块和高级功能模块，如各种滤波器，PI控制器和积分器。NC1131-3可以创建参数，故障信息和其他与应用相前的特性。本系统具有较大的实用和推广价值。     

基于AT89C52的温室用温度监控系统设计

针对目前农业的发展由粗放型向节约型转变的需要,设计一套以AT89C52单片机为核心,与外围器件数字温度传感器DS18B20、数码管、按键、电风扇和加热片共同构成的温度监控系统.该系统能够根据实测温度偏离设定温度值的程度由单片机驱动继电器自动启动相应的加热和降温设备,实现对设定参数的闭环调节,从而将温度保持在恒温,较大程度上节约农业生产人力资源.经实验验证,该系统具有较高的测量精度和控制精度.     

设施农业大棚多点温度采集报警装置

对于农业大棚采用单个温度传感器测温不准,难以精准控制的问题,本文介绍了一种基于DS18B20单总线温度传感器的设施农业大棚多点温度采集报警装置的设计.该系统主要由AT89C51单片机、DS18B20单总线温度传感器检测电路、报警电路和显示电路构成.通过Proteus平台的仿真和调试,系统可以把采集到的各点温度值加以运算并且求出平均值,然后在显示器上显示出来,从而可以验证其在实际应用中的可行性.     

基于小波分析的比色测温波段选择

基于辐射测温原理,介绍了比色测温理论,为提高钢水的测温精度,对比色测温波长进行了最佳选择。搭建实验平台,获得了不同温度下的熔融金属辐射亮度曲线,通过小波去噪方法获得信噪比较高的亮度曲线,利用Matlab软件作出了波长选择的GUI界面。当滤波片中心波长选择为λ1=580nm,λ2=590nm时,测量误差满足了测量精度要求。