study on temperature effect of ISFET devices

• Main Authors: tang, kuo i, 唐國益
• Other Authors: Jyh-Ling Lin
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/31702910935348730320

碩士 === 華梵工學院 === 電子研究所 === 85 === ABSTRACT Ion-sensitive field effect transistors (ISFETs) exist some instable characteri- stics, such as time drift, thermal instability and hysteresis,where the thermal instability is the dominate term to affect device preformance. In some applica tion cases ,ISFETs are measured in a temperature -vairation environment. Theref -ore the temperature effects of ISFETs are a valuable reseraching topic.In the thesis, some theoretical analysis of the ISFETs characteristics is studied . It is mainly based on a site-binding model and MOSFET theory. some samples from laboratory fabrication and commercial prod uction were measured by HP4284A to obtain C-V curves and also by HP4145B to ob tain I-V curves with temperature variation . In actual measuring ,Frist, we fin that if we want to operate ISFETs on stable condition,the process technology o f MOSFET fabrication must be well to obtain a good insulator / semicon-ductor interface . second, when devices baised on a appropriate operating point ,the o utput temperature coefficient can be de caresed. Farther,we can get a zero temperature coefficient point,and introduce the idea of a zero temperature coefficient point of constant drain current circ uit to do a simple temperature compensation ,In addition,we can reduce temperat ure coefficient of ISFETs by selecting appropriate devices fabrication conditio n. key word ion-sensitive field effect transistors ,site-binding model