1/f noise in ion selective field effect transistors compared to MOSFETs
18 May 1998-Vol. 2, pp 1456-1460
TL;DR: In this paper, measurements of low frequency noise in pH ISFETs are presented and compared to similar measurements performed in MOSFET, in the frequency range between 1 Hz to 100 kHz.
Abstract: pH ISFETs are very interesting sensors for biomedical microsystems including in vivo measurements of pH. The noise phenomena and related resolution of these sensors are still not understood. In this paper measurements of low frequency noise in pH ISFETs are presented and compared to similar measurements performed in MOSFETs. Various bias conditions are used corresponding to the gate voltage changing from subthreshold to saturation, in the frequency range between 1 Hz to 100 kHz ISFET noise measurements were performed in solutions with pH in the range of pH4 to pH10, at room temperature. The measured ISFETs exhibit clearly 1/f noise. The dependence of the drain current noise power spectral density upon average drain current follows the same behavior of 1/f noise that the observed in MOSFETs. The measured noise characteristics shown here indicate that the Si/SiO/sub 2/ interface dominates the noise behavior of the ISFET. No pH dependent effects are observed and the interface between the solution and the gate insulator does not contribute measurable noise.
Citations
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01 Oct 2006
TL;DR: In this article, a pH sensor using charge transfer technique is proposed to increase a sensing signal without an extra amplifier, it is expected that charge transfer type pH sensor increases sensitivity and decreases random noise.
Abstract: We present about a pH sensor, which is capable of measuring high sensitivity using charge transfer technique. The sensitivity of pH was obtained 1130 mV/pH by charge accumulation operation. The proposed pH sensor using charge transfer technique is possible to increase a sensing signal without an extra amplifier. It is expected that charge transfer type pH sensor increases sensitivity and decreases random noise.
46 citations
Cites background from "1/f noise in ion selective field ef..."
...The detectable limit of an ISFET is restricted by the 1/f noise of the drain current, because the ISFET is driven in a DC mode usually [6], [7]....
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10 Jun 2007
TL;DR: In this article, a super high sensitivity charge transfer type pH sensor was proposed, which achieved a pH sensitivity of 5048 mV/pH, which is approximately 100 times higher than the ISISFET.
Abstract: We successfully fabricated a super high sensitivity charge transfer type pH sensor. The proposed pH sensor is possible to amplify the sensing signals without an external amplifier by accumulation cycle. The pH sensitivity was obtained 5048 mV/pH, which is approximately 100 times higher than the Ion Sensitive Field Effect Transistor (ISFET), which is the most familiar pH sensor using semiconductor. This is the highest sensitivity of pH in the past. The performance of this charge transfer type pH sensor is equal with glass electrode type pH sensor. In addition, the charge transfer type pH sensor has much possibility to exceed the glass electrode method.
45 citations
Cites background from "1/f noise in ion selective field ef..."
...Eng., vol. BME-17, pp.70-71, 1970 [2] C. G. Jakobson, Y. Nemirovsky, “1/f noise in ion sensitive field effect transistors compared to MOSFETs”, Proc....
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...The ideal maximum sensitivity of the ISFET, which is the most familiar pH sensor using semiconductor, is 59mV/pH from the Nernst equation [1], and the resolution of the ISFET is 0.1pH which is restricted by the 1/f noise in MOSFETs [2]....
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...1pH which is restricted by the 1/f noise in MOSFETs [2]....
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13 Jan 2015
TL;DR: In this paper, two different noise reduction techniques for ion sensitive field effect transistor (ISFET) readout configuration and their comparison are presented, and the proposed circuit configurations are immune to the noise generated from the ISFET sensory system and particularly to low frequency pH dependent 1/f electrochemical noise.
Abstract: This paper presents two different noise reduction techniques for ion sensitive field effect transistor (ISFET) readout configuration and their comparison. The proposed circuit configurations are immune to the noise generated from the ISFET sensory system and particularly to the low frequency pH dependent 1/f electrochemical noise. The methods used under this study are compensation of noise by differential OPAMP based and Wheatstone bridge circuit, where two identical commercial ISFET sensors were used. The statistical and frequency analysis of the data generated by this two methods were compared for different pH value ranging from pH 2 to 10 at room temperature, and it is found that the readout circuits are able to compensate the noise to a great extent.
15 citations
25 Sep 2014
TL;DR: In this paper, three different noise reduction techniques for ISFET readout configuration and their comparison is presented, and it is found that the interface circuits are able to compensate the noise to a great extent by compensation of noise by differential techniques (Implemented in LabVIEW environment and with OPAMP based circuit) and compensation by Wheatstone bridge method.
Abstract: In this paper three different noise reduction techniques for Ion Sensitive Field Effect Transistor (ISFET) readout configuration and their comparison is presented. The proposed circuit configurations are immune to the noise generated from the ISFET sensory system and particularly to the low frequency pH dependent 1/f electrochemical noise. The methods used under these studies are- Compensation of noise by differential techniques (Implemented in LabVIEW environment and with OPAMP based circuit) and compensation by Wheatstone bridge method. Here two identical commercial ISFET sensors from Microsens were used. The statistical and frequency analysis of the data generated by the proposed methods were compared for different pH value ranging from pH-2 to pH 10 under room temperature, and it is found that the interface circuits are able to compensate the noise to a great extent.
4 citations
01 Jan 2006
TL;DR: PH sensor, which iscapable of measuring highsensitivity using charge transfer technique, is presented, expected that charge transfer type pH sensor increases sensitivity and decreases random noise.
Abstract: We present aboutapH sensor, whichiscapable of measuring highsensitivity usingchargetransfer technique. Thesensitivity ofpH wasobtained 1130mV/pHbycharge accumulation operation. Theproposed pHsensor using charge transfer technique ispossible toincrease a sensing signal without anextraamplifier. Itisexpected thatcharge transfer typepH sensorincreases sensitivity anddecreases random noise.
References
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TL;DR: In very small electronic devices, the alternate capture and emission of carriers at an individual defect site generates discrete switching in the device resistance, referred to as a random telegraph signal (RTS) as mentioned in this paper.
Abstract: In very small electronic devices the alternate capture and emission of carriers at an individual defect site generates discrete switching in the device resistance—referred to as a random telegraph signal (RTS) The study of RTSs has provided a powerful means of investigating the capture and emission kinetics of single defects, has demonstrated the defect origins of low-frequency (1/ƒ) noise in these devices, and has provided new insight into the nature of defects at the Si/SiO2 interface
1,094 citations
"1/f noise in ion selective field ef..." refers background in this paper
...The relationship between Eq. 1 and the physical modcl is presented in [ 21 ]....
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TL;DR: In this article, the authors studied resistance fluctuation in submicrometer narrow Si inversion layers over a wide range of temperatures and electron concentrations, caused by the capture and emission of individual electrons at strategically located scatterers (interface traps).
Abstract: Resistance fluctations in submicrometer narrow Si inversion layers are studied over a wide range of temperatures and electron concentrations. Thermally activated switching on and off of discrete resistance increments is observed, caused by the capture and emission of individual electrons at strategically located scatterers (interface traps). The traps have a broad distribution of activation energies, as assumed in accounting for $\frac{1}{f}$ noise in larger devices.
617 citations
TL;DR: In this paper, a generalized theory for the current-voltage characteristics of an EISFET in electrolyte solutions is presented, based on a model of surface ionization and complexation of surface hydroxyl groups.
Abstract: A model of surface ionization and complexation of surface hydroxyl groups on the gate insulator surface is adapted in conjunction with electronic device physics to arrive at a generalized theory for the current-voltage characteristics of an electrolyte-insulator-semiconductor field-effect transistor (EISFET) in electrolyte solutions. EISFET's that employ thermally grown silicon dioxide were tested in simple electrolytes that contain Na+, K+, and Li+ions titrated in a p H range from 2 to 9. Experimental results show good agreement with the theory. The model successfully explains p H sensitivity, as well as the ion interference effect, of the EISFET working as a p H sensor. From this model, it is conluded that, among all the electrolyte parameters associated with an EISFET, the surface site density of the hydroxyl groups N s and the separation of surface ionization constants \Delta pK are the primary factors to consider when employing EISFET's as p H sensors. For high sensitivity and good selectivity, large N s and small \Delta pK values are required.
320 citations
TL;DR: In this article, the power spectral densities of the gate voltage and drain current were investigated under various bias conditions ranging from subthreshold to saturation, and it was found that it is advisable to limit the bias voltages to values that are experimentally determined from the transconductance characteristics and correspond to a nearly constant channel mobility.
Abstract: Detailed noise measurements of the 1/ f noise in p - and n -mos transistors for analog applications are reported under various bias conditions ranging from subthreshold to saturation. The CMOS transistors under study have a relatively large area, exhibit long channel behavior and are fabricated in a commercial “low noise process”, as prescribed for analog applications. A clear methodology and useful models for the power spectral densities of the gate voltage and drain current are presented and are based on recent studies in sub-micron transistors that have established the physical origin of 1/ f noise in MOS transistors. In saturation, it is found that it is advisable to limit the bias voltages to values that are experimentally determined from the transconductance characteristics and correspond to a nearly constant channel mobility. The experimentally observed reduction in channel mobility indicates the existence of strong fields that induce additional oxide charging and hence an increase in the effective density of oxide traps and the noise. In the bias voltages where channel mobility is nearly constant, the measured input-referred noise power is practically constant. Below threshold voltage, a reduction is observed in the input-referred noise as gate voltage is decreased, corresponding to the prediction of the model and due to the exponential reduction of the inversion capacitance with gate voltage. This behavior is observed for both n -mos and p -mos transistors.
116 citations
TL;DR: A review of different microtechnologies for the fabrication of pH ion sensitive field effect transistor (ISFET) sensors is presented in this paper, where both front-side and back-side contacted devices are studied, in order to determine the compatibility of different processes, devices and materials with standard CMOS technologies.
76 citations