Temperature Compensation Circuit for ISFET Sensor

Abstract

PH measurements are widely used in agriculture, biomedical engineering, the food industry, environmental studies, etc. Several healthcare and biomedical research studies have reported that all aqueous samples have their pH tested at some point in their lifecycle for evaluation of the diagnosis of diseases or susceptibility, wound healing, cellular internalization, etc. The ion-sensitive field effect transistor (ISFET) is capable of pH measurements. Such use of the ISFET has become popular, as it allows sensing, preprocessing, and computational circuitry to be encapsulated on a single chip, enabling miniaturization and portability. However, the extracted data from the sensor have been affected by the variation of the temperature. This paper presents a new integrated circuit that can enhance the immunity of ion-sensitive field effect transistors (ISFET) against the temperature. To achieve this purpose, the considered ISFET macro model is analyzed and validated with experimental data. Moreover, we investigate the temperature dependency on the voltage-current (I-V). Accordingly, an improved conditioning circuit is designed in order to reduce the temperature sensitivity on the measured pH values of the ISFET sensor. The numerical validation results show that the developed solution accurately compensates the temperature variation on the measured pH values at low power consumption.

Design of a Broadband MMIC Driver Amplifier with Enhanced Feedback and Temperature Compensation Technique

“…A fluctuating current of the power amplifier affects other components. The change of ambient temperature has a significant impact on the static bias of the transistor [23][24][25][26]. With the aim of improving the influence of temperature changes on the bias state, we first analyzed the characteristics of the transistor with temperature changes under the process.…”

Temperature Effect Analysis of the Enzymatic RuO2 Biomedical Sensor for Ascorbic Acid Detection

“…EMPERATURE influence is one of the important issues for biomedical sensors. Most temperature compensation mechanisms were based on ion-sensitive field-effect transistor (ISFET) sensors [1][2][3][4][5]. ISFET was first proposed by Bergveld [6].…”

“…Furthermore, the metal gate is replaced by an ion-sensitive membrane, electrolyte solution, and reference electrode. Gaddour et al [1] used two ISFETs with the same electrical and chemical characteristics for temperature compensation, called ISFET and reference field effect transistor (ReFET). ReFET sensor can significantly reduce drift and noise of measurement.…”

Analysis of CMOS Extended-Gate Field-Effect Transistor With On-Chip Window Based on Uricase/RuO2 Sensing Film

“…Hence, they designed a dry test method to avoid these non-ideal effects. A study by Gaddour et al proposed a temperature compensation circuit for ISFET [13].…”

“…For this study, the RuO2 was used as the passivation layer on the top metal of the sensing window. Although plenty of research studies on ISFET for pH sensing have been conducted recently [10][11][12][13][14], very few explored analytes, enzymes, and catalysts together. In the present study, we fabricated an EGFET device for uric acid (UA) detection.…”