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991.
Cheng Tung Huang Tan Fu Lei 《Electron Devices, IEEE Transactions on》1997,44(4):601-606
A new technology for forming a titanium-silicide shallow junction by combining germanium implantation with an amorphous-silicon (or a poly-silicon) buffer layer has been proposed for MOSFETs. The use of a buffer layer between Ti and Si can avoid the consumption of bulk-silicon and the recession of TiSi2 film into the source/drain junctions during the silicidation process. In this study, the important role of germanium-implantation on the formation of TiSi2 contacted p+/n junctions was examined. After subsequent implantation of Ge+ and B+ into the TiSi2 film, samples were annealed at different temperatures to form p +/n junctions and C54-TiSi2. Since the penetration of titanium atoms was suppressed due to the germanium-implantation, the periphery leakage and the generation leakage were improved and TiSi2/Si interfaces were even smooth. Therefore, p+/n junctions with a very low leakage current (0.192 nA/cm 2 at -5 V) and an excellent forward ideality factor (n≈1.002) can be obtained. From the secondary ion mass spectrometry (SIMS) analysis, the junction depth is 400 相似文献
992.
993.
本文介绍了通信发展的状况和 B-ISDN 的特性,重点提出现有局域网、N-ISDN 网络与B-ISDN 网络互连的策略,以及面向21世纪宽带通信网的网络结构。最后简述了通信业务的发展趋势及利用 ATM/B-ISDN技术改造中国现有通信网的设想。 相似文献
994.
Nie Jingnan Cheng Shixin You Xiaohu 《电子科学学刊(英文版)》1997,14(3):285-288
In a CDMA communication network using conventional signal detection, system capacity is limited and its performance is degraded by the multi-access interference (MAI). Multiuser detection, which makes use of cross-correlation information between spread spectrum codes, can reduce or eliminate the MAI in a Gaussian channel so as to mitigate the near-far effects and increase the system capacity. This paper extends the multiuser detector to a flat Rayleigh fading CDMA environment, and discusses the bit error rate of typical multiuser detection algorithms in such a environment by combining theoretical analysis and computer simulation. It is shown that multiuser detection is superior to conventional detections in the flat Rayleigh fading channels. 相似文献
995.
现代电信网运行维护的技术支持系统 总被引:1,自引:0,他引:1
在电信网达到一定规模,网路建设速度放慢之时,在设备 应商的名费技术支持到期后,数千万端口多种型号的交换设备和大量传输设备的技术支持由谁来承担?中国电信将采用什么策略 技术手段来保障维护部门能及时得到优质高效的技术支持?本文作者长期从事本地网网管和集中监控系统的开发和工程实施,深深感到与网管配套的运行维护技术支持系统在电信支撑网的建设中的重要性。 相似文献
996.
文章报道了空间多光谱扫描仪红外波段多元光导碲镉汞探测器的研制与优值。重点研究并解决了多元器件光谱曲线不一致性的问题,简述了器件的优值波段响应率RΔλ1,波段探测率DΔλ和单色响应率Rλ的测试定标方法,以及器件按空间环境使用要求经历老炼和环境条件试验的情况。测试结果表明多元件性能稳定可靠,各项指标均达到了空间多光谱扫描仪的技术要求。 相似文献
997.
998.
999.
Slot antennas on photonic band gap crystals 总被引:1,自引:0,他引:1
Leung W.Y. Biswas R. Shi-Di Cheng Sigalas M.M. McCalmont J.S. Tuttle G. Ho K.-M. 《Antennas and Propagation, IEEE Transactions on》1997,45(10):1569-1570
The radiation patterns of a slot antenna placed on a photonic band gap crystal have been measured. We used a layer-by-layer photonic band gap crystal having a three-dimensional stop band between 12 and 15 GHz. The slot antenna radiation depends sensitively on the relative position and orientation of the slot in the surface unit cell of the photonic crystal. We have found configurations of the slot antenna with an increase of radiated power by 2-3 dB. The photonic band gap crystal can considerably improve the performance of a simple slot antenna 相似文献
1000.
Sei-Wang Chen Chi-Farn Chen Meng-Seng Chen Shen Cheng Chiung-Yao Fang Kuo-En Chang 《Signal Processing, IEEE Transactions on》1997,45(11):2639-2654
An unsupervised classification technique conceptualized in terms of neural and fuzzy disciplines for the segmentation of remotely sensed images is presented. The process consists of three major steps: 1) pattern transformation; 2) neural classification; 3) fuzzy grouping. In the first step, the multispectral patterns of image pixels are transformed into what we call coarse patterns. In the second step, a delicate classification of pixels is attained by applying an ART neural classifier to the transformed pixel patterns. Since the resultant clusters of pixels are usually too keen to be of practical significance, in the third step, a fuzzy clustering algorithm is invoked to integrate pixel clusters. A function for measuring clustering validity is defined with which the optimal number of classes can be automatically determined by the clustering algorithm. The proposed technique is applied to both synthetic and real images. High classification rates have been achieved for synthetic images. We also feel comfortable with the results of the real images because their spectral variances are even smaller than the spectral variances of the synthetic images examined 相似文献