Radiation Effect on MOS Devices and Aspect Ratio Design Consideration in CMOS Inverters

　　　　　本文研究輻射對n-及p-通道金氧半場效電晶體之效應及元件比對互補 金氧半反相器抗輻射能力的影響。實驗發現，鈷六十輻射會對金氧半場效電晶體 之電特性造成很嚴重之衰退現象。而且，從實驗知道使用大元件比的互補金氧半 反相器，在照射輻射後其有較小的臨限電壓偏移量，但是其時間反應特性會變 差，而且會產生不對稱的時間特性。因此，要製作一個具有抗輻射能力的互補金 氧半反相器，決定其元件比時，必須同時考慮其因輻射後臨限電壓的偏移量和其 時間的反應特性，取其折衷值。
　　　　　The radiation effect on n- and p-MOSFET's and the dependency of the radiation hardness of CMOS inverters on their aspect ratios are studied in this work. Itis experimentally observed that the electrical characteristics of MOSFET's can beseriously degraded by Co-60 irradiation. Also, it is found that a CMOS inverterwith a large aspect ratio should sustain a small logic threshold voltage shift due toradiation, whereas its switching time becomes poor and exhibits an asymmetric performance. One should consider both of the threshold voltage shift and the switchingtime degradation in determining the aspect ratio for a radiation hard CMOS inverter.