HYDROGEN DIFFUSION IN A-SI-H/A-SI STRUCTURE UNDER ELECTRICAL BIAS

By using the technique of elastic recoil detection (ERD), we have measured the hydrogen profiles in a-Si:H/a-Si structure samples annealed at various temperatures with and without electrical bias, and investigated the influence of electrical bias on hydrogen diffusion. The results show that hydrogen diffusion in a-Si is significantly enhanced by the action of electrical bias. The existence of the excess carriers, which are introduced by electrical injection, is considered to be responsible for the enhancement of hydrogen diffusion, and the microprocess of hydrogen transport has been exploited.

一种基于改进的极值中值滤波算法

提出的改进的极值中值滤波(IEM)算法是在极值中值滤波(EM)算法的基础上做了如下两点改进.首先,采用更合理的检测方法来检测噪声点,减小将信号点误判为噪声点的概率.其次,采用改进的滤波算法,解决了当噪声点个数大于像素总数一半时,传统中值滤波无能为力的问题.实验证明,当噪声密度很大时,IEM方法不仅比EM方法有更好的滤波效果,而且能够更好地保护图像细节.

Design and Fabrication of Power Si1-xGex/Si Heterojunction Bipolar Transistor for Wireless Power Amplifier Applications

A multi-finger structure power SiGe HBT device （with an emitter area of about 166μm^2） is fabricated with very simple 2μm double-mesa technology. The DC current gain β is 144.25. The B-C junction breakdown voltage reaches 9V with a collector doping concentration of 1 × 10^17cm^-3 and a collector thickness of 400nm. Though our data are influenced by large additional RF probe pads, the device exhibits a maximum oscillation frequency fmax of 10.1GHz and a cut-off frequency fτ of 1.8GHz at a DC bias point of IC=10mA and VCE = 2.5V.

MOCVD生长的InGaN合金的性质

对使用MOCVD方法在蓝宝石衬底上生长的典型InGaN样品进行了光致发光(PL)、霍耳(Hall)及扫描电镜(SEM)测量。结果表明