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摘要国家越来越重视生态环境的建设，人们也对生态建设十分关心，对于现在环境下各个地区水质监测的复杂环境，pH值传感器有助于水质环境污染监测。pH值的测量在现代工业、农业、生物医学工程、环境科学等研究和应用领域中都是十分必要的。pH传感器的应用前景较为广泛pH的监测应用较为广泛，可用于农业，酿造业，乳制品行业，印染行业，化肥生产等行业。而且随着科学技术的发展，传统的pH传感器已不能满足人们的需求，需要新型传感器，比如光导纤文pH化学传感器、pH-ISFET化学传感器和pH酶化学传感器。39652
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本设计结合传统传感器的缺点与化学传感器的优点，提出了基于ISFET的pH传感器设计方案。本设计的pH传感器比传统的传感器更加的操作简单，并且它的监测速度快，准确度、灵敏度高。本文首先分析了ISFET器件的基本结构，再研究了ISFET的工作原理，从而推导出氢离子活度与界面电势的关系表达式，并根据表达式分析影响此传感器的各类影响因素。通过观察ISFET与MOSFET的结构，不难发现它们之间很相似，所以可以利用离子敏感膜来代替MOSFET的金属栅极，再根据金属-氧化物半导体场效应晶体管（MOSFET）的电压电流特性，推导出离子敏场效应晶体管（ISFET）的电流电压等特性方程。同时通过在电路模拟程序上进行仿真模拟，由MOSFET为原型，经过细微的处理转化成ISFET的模型，这时将ISFET的模型进行仿真。通过仿真得出的特性曲线可以比较真实的反映出离子敏场效应晶体管ISFET的电学特性。
毕业论文关键词: 离子敏场效应晶体管 pH传感器 SPICE模型
Abstract
The country pay more and more attention to the construction of ecoloegiceal environment, people also concvern about the ecologiceal environment,For the complex environment of mater quality detection in various parts of the environnment,the pH sensor is helpful for the detection of matcter pollcution.The measurement of pH values is essentiaol in modern industry ,agriculture,biomedical engineering, environmental science and so on.The application of PH sensor is widely used in the monitoring of PH,and can be used in agriculture,brewing industry,printing and dyeing industr,chemical fertilizer production and other industries.
pH sensor monitoring applications prospect of more extensive pH is more widely available for agriculture, brewing industry, dairy industry, printing and dyeing industry, fertilizer production and other industries. With the development of science and technology, traditional pH sensor can not meet people's needs, we need new sensors, such as fiber optic chemical sensor pH, pH-ISFET chemical sensors and chemical sensors pH enzyme.
This design combines the advantages and disadvantages of conventional sensors and chemical sensors is proposed based on ISFET pH sensor design. The design of the pH sensor is more than the traditional sensor is simple, and its monitoring of speed, accuracy, and high sensitivity. This paper analyzes the basic structure of the ISFET device, and then study the ISFET works, to derive the relationship between the expression of hydrogen ion activity and interfacial potential, and to analyze all kinds of factors that influence this sensor according to expression. By observing ISFET and MOSFET structure, difficult to find very similar between them, so you can make use of an ion-sensitive membrane instead of a metal gate MOSFET, according to the metal - oxide semiconductor field effect transistor (MOSFET) voltage-current characteristics are derived an ion-sensitive field effect transistor (ISFET) of the current voltage characteristic equation. At the same time by performing simulation on circuit simulation program by MOSFET as the prototype, after minor treatment converted ISFET model, then the model will simulate ISFET. The simulation results of the characteristic curve can be relatively reflect the real ion sensitive field effect transistor ISFET electrical characteristics.