An ion-sensitive field effect transistor(ISFET)can be achieved by CMOS technology. If a polysilicon layer is kept on the oxide layer of the gate and connected to an external metal layer as a floating gate, a floating gate ISFET can be realized. Based on the sensing mechanism of ISFET and the site-binding model,the physical model of the floating gate ISFET is established from HSPICE. The influence of the membrane resistance, capacitance and the line parasitic capacitance on the dynamic characteristics of delay time and hysteresis is investigated, its static characteristics are also simulated and the results agree with experiments.%采用CMOS工艺可以实现离子敏场效应型晶体管(ISFET),若在栅极氧化层之上保留多晶硅层,并通过引线使其与 外界的金属层相连作为悬浮的栅极,可实现悬浮栅结构ISFET.从ISFET的传感机理出发,根据表面基模型,利用HSPICE建 立了悬浮栅结构ISFET的物理模型.以该模型为研究对象,探讨了薄膜等效电阻、薄膜等效电容、互连线寄生电容和寄生电阻 等因素与动态特性中延迟时间和迟滞等因素的关系,并对其静态特性进行仿真,仿真结果和试验数据基本相符.
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