Light effect characterization of ISFET based pH sensor with Si&lt;inf&gt;3&lt;/inf&gt;N&lt;inf&gt;4&lt;/inf&gt; gate insulator

Noh, Nurul Izzati Mohammad; Yusof, Khairul Aimi; Abdullah, Ali Zaini; Herman, Sukreen Hana; Fazlida, Wan; Abdullah, Hanim

doi:10.1109/iscaie.2014.7010214

Cited by 3 publications

(2 citation statements)

References 16 publications

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“…1: Cross section of sensing elements, showing an ISFET and a moisture sensor maximum pH resolution. Although few models have been proposed for predicting analytically the drift evolution [9], the influence of external phenomena such as lighting conditions or Ag/AgCl reference electrode potential introduce uncertainty to these models and prevents its real-time compensation [10]. Lastly, fluid leakage between reaction wells on LoC platforms remains a significant issue, and to the best of our knowledge there is no mechanism to analyse leakage in real-time without modifying the Ag/AgCl reference electrode potential, which in turn varies the reaction drift.…”

Section: Introductionmentioning

confidence: 99%

A Multi-Sensing ISFET Array for Simultaneous In-Pixel Detection of Light, Temperature, Moisture and Ions

Hua

Cacho-Soblechero

Georgiou

2021

2021 IEEE International Symposium on Circuits and Systems (ISCAS)

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This paper presents a multi-sensing pixel capable of sensing ion concentration, temperature, moisture and light from the same spatial point. The presented pixel is composed of an ISFET chemical sensor, a light sensor, a moisture sensor and a temperature sensor, all implemented in standard CMOS technology in a compact pixel. All sensing modalities are acquired simultaneously and modulated onto a single waveform using multi-frequency PWM modulation, overcoming the associated transmission overhead. Furthermore, ISFET non-idealities such as trapped charge are compensated through a global DAC, balancing the input linear OTA, while the light sensor dark current is mitigated in-pixel by subtracting its influence using a reference photodiode. The proposed pixel occupies 50x50 µm 2 , and it is integrated as part of a 4x4 multi-sensing array, along with on-chip biasing, instrumentation and digital control. To the best of our knowledge, this architecture represents the first multisensing architecture capable of extracting four features from the same spatial point simultaneously, enabling ISFET-based platforms to sense both the chemical signal and the external conditions influencing its measurement.

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Section: Introductionmentioning

confidence: 99%

A Multi-Sensing ISFET Array for Simultaneous In-Pixel Detection of Light, Temperature, Moisture and Ions

Hua

Cacho-Soblechero

Georgiou

2021

2021 IEEE International Symposium on Circuits and Systems (ISCAS)

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“…The principle of this structure is to measure the activity of [H + ] ions in the electrolyte or liquid solution, ion exchange will happen between [H + ] and metal membrane ions . Both the extended membrane and reference electrode were dipped in the electrolyte to create charge between them then can find the sensitivity, stability and reliability of the membrane [6].…”

Section: Introductionmentioning

confidence: 99%

Using Deionized Water with Ethanol as a Solvent of CuS EGFET as pH Sensor

Sabah

Ahmed

Hassan

et al. 2017

MSF

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In this research work, copper sulphide was deposited on glass substrate using spray pyrolysis deposition. The precursors were dissolved in deionized water (DIW) and ethanol, mixed at a ratio of 7:3. The distance between nozzle and substrate was 30 cm and the substrate temperature was maintained at 200 °C. XRD spectra analysis showed four distinctive peaks of high intensity, which indicate pure CuS covellite phase with average crystallite size of 28.3 nm. FESEM characterization of the thin film structure showed a mixture of very small nanoplates and larger square-and triangular-shaped particles. The application of the film as pH sensor showed it has exceptional qualities that include sensitivity and linearity of 22.9 mV/pH and 93.8%, hysteresis of 23.75 mV, repeatability (C.V.) of 0.11% for pH7, stability and reliability (C.V.) of 0.13%, 0.12% and 0.08% for pH 4, 7 and 10, respectively. This research work confirms the feasibility of using CuS thin film as extended membrane in pH sensor and biosensor applications.

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Effect of Light on the Sensitivity of CuS Thin Film EGFET Implemented as pH Sensor

Sabah¹

2016

International Journal of Electrochemical Science

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The lightness and darkness affect the sensitivity of thin films considered as extended-gate field-effect transistor (EGFET) for pH sensor, for this reason the research work was investigated to study these effects for CuS thin film. CuS thin film prepared by copper chloride and sodium thiosulfate using deionized water as a solvent, deposited on a glass substrate by spray pyrolysis deposition. The structural properties were studied through X-ray diffractometer, and the morphological properties were studied through field emission scanning electron microscopy. Then this thin film was used as an extended gate of the field effect transistor to be implemented as pH sensor. The sensitivity was measured for this extended gate under two conditions; dark and light source. The results showed the highest sensitivity (23 mV/pH) and less hysteresis (2.6 mV) and drift (13.1, 73.5 and 85.8 for pH4, pH7 and pH10, respectively) of the sensor in dark. While under high-intensity white light the sensitivity was (19 mV/pH) and the hysteresis had the value (5.2 mV) and drift values were (21.7, 155.8 and 90.4 for pH4, pH7 and pH10, respectively). This confirmed that the extended gate of the field effect transistor is sensitive to light, and the light decreased the pH sensitivity.

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Light effect characterization of ISFET based pH sensor with Si<inf>3</inf>N<inf>4</inf> gate insulator

Cited by 3 publications

References 16 publications

A Multi-Sensing ISFET Array for Simultaneous In-Pixel Detection of Light, Temperature, Moisture and Ions

A Multi-Sensing ISFET Array for Simultaneous In-Pixel Detection of Light, Temperature, Moisture and Ions

Using Deionized Water with Ethanol as a Solvent of CuS EGFET as pH Sensor

Effect of Light on the Sensitivity of CuS Thin Film EGFET Implemented as pH Sensor

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