Computer aided measurement of the electromagnetic parameter for the microwave absorbing materials

The electromagnetic parameters of microwave absorbing materials are important criteria when appraising the properties of absorbents. For reconstruction of parameters which belongs to the inverse scattering problem, the test data in requirement of traditional impedance method are "just enough" and not "redundant" to comprehensively evaluate the electromagnetic properties of materials. A novel optimization approach involving multiple impedance measurements is introduced in this paper to implement automatic measurement for electromagnetic parameters on microwave slot-line. Some results for standard samples and microwave absorbing materials are given.     

STAGNANT LAYER EFFECT IN CVD PROCESS

It is clearly shown that the stagnant layer effect is present in entire temperature range in CVD process by pyrolysis of silane. The Curves in logarithmic growth rate vs reciprocal temperature plot can be divided into three straight line ranges. In high temperature region the rate-controlling mechanism is the diffusion of silicon atoms, but not of silane, which pass through the stagnant layer after thermal decomposition of silane. In intermediate and low temperature region the growth rate-controlling factor is the decomposition rate of silane in the stagnant layer, but not the surface reaction process. Owing to the difference in ratecontrolling mechanism the growth rate has different dependences on the height of stagnant layer. In intermediate and low temperature region the growth rate is proportional to the stagnant layer height, but in high temperature region it is inversely proportional to the square of the stagnant layer height.     

微波吸收材料电磁参数的计算机辅助测量

微波吸收材料的电磁参数在评价吸收剂性能时是一个重要指标。参数重建于电磁逆散射问题，而传统的阻抗方法仅利用“正好足够”的测试数据来获取电磁参数，未能利用“冗余”数据对材料的电磁性能作综合评定。本文介绍结合网络参数的多点测量阻抗的优化方法，在测量线上实现了电磁参数的自动测量。文中给出了标准样品和吸收材料的实测结果。     

评定异质硅膜质量的光学方法——光“吸收因子”法

<正> 目前,异质硅膜作为半导体器件材料已受到大家重视,其中以蓝宝石为衬底的气相外延硅片(SOS)已成功地应用于表面场效应集成电路的生产中。外延膜的质量对电路的性能起着关键作用,因此对薄膜质量的检测与控制,     

微波吸收材料电磁参数的计算机辅助测量

微波吸收材料的电磁参数在评价吸收剂性能时是一个重要指标。参数重建属于电磁逆散射问题,而传统的阻抗方法仅利用正好足够的测试数据来获取电磁参数,未能利用冗余数据对材料的电磁性能作综合评定。本文介绍结合网络参数的多点测量阻抗的优化方法,在测量线上实现了电磁参数的自动测量。文中给出了标准样品和吸收材料的实测结果。     

硅的气相淀积的滞流层效应

在整个硅烷分解化学淀积硅膜的试验温度范围内,都显示出滞流层效应。对数生长速率与温度倒数的曲线分为三段直线。高温区的速率控制机制是硅烷分解后的硅原子;而不是硅烷通过滞流层的扩散机制控制了生长速率。中低温区的速率控制机制是硅烷分解,而不是表面反应过程控制生长速率。速率控制机制的不同,生长速率与滞流层高度的依赖关系就不同:在中低温区生长速率与滞流层高度成正比;在高温区生长速率与滞流层高度的平方成反比。     

SOS外延膜的光吸收研究

<正> SOS(蓝宝石上外延硅)膜是异质外延,由于点阵失配、外延后冷却时产生的热应力及自掺杂效应,外延膜的结晶质量及半导体性能对于衬底制备及外延工艺参数非常敏感.Druminski等根据SOS膜的光谱反射吸收测量,提出用一光吸收因子F_A来表征硅膜的结晶质量.F_A定义为