The influence of surface oxidation on the pH-sensing properties of silicon nitride

Mikolajick, Thomas; Kühnhold, R; Schnupp, R; Ryssel, H.

doi:10.1016/s0925-4005(99)00125-2

Cited by 26 publications

(20 citation statements)

References 9 publications

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“…It is also well established that the surface potential change of SiO 2 as a function of pH ranges from 40-60 mV/ pH depending on the density and activation of surface cites, buffer ionic strength, and composition. 10 In the ideal case, a purely Nernstian response will give a surface potential sensitivity of 2.3kT / q V / pH, 11 which places a fundamental limit on the best case sensitivity. Change in current is limited to at most one decade per one unit pH change of the buffer ͑1 decade/ pH͒.…”

Section: Nanoscale Thickness Double-gated Field Effect Silicon Sensormentioning

confidence: 99%

Nanoscale thickness double-gated field effect silicon sensors for sensitive pH detection in fluid

Elibol

Reddy

Bashir

2008

Applied Physics Letters

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In this work, we report on the optimization of a double-gate silicon-on-insulator field effect device operation to maximize pH sensitivity. The operating point can be fine tuned by independently biasing the fluid and the back gate of the device. Choosing the bias points such that device is nearly depleted results in an exponential current response—in our case, 0.70decade per unit change in pH. This value is comparable to results obtained with devices that have been further scaled in width, reported at the forefront of the field, and close to the ideal value of 1decade∕pH. By using a thin active area, sensitivity is increased due to increased coupling between the two conducting surfaces of the devices.

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Section: Nanoscale Thickness Double-gated Field Effect Silicon Sensormentioning

confidence: 99%

Nanoscale thickness double-gated field effect silicon sensors for sensitive pH detection in fluid

Elibol

Reddy

Bashir

2008

Applied Physics Letters

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“…The oxygen-rich layer on the Si 3 N 4 film may also reduce the number of sites contributing to the site binding. 14) Okada and Matumura reported that oxygen is absorbed in a shallow surface region of Cat-CVD deposited Si 3 N 4 film. 9) To improve pH sensitivity and uniformity, one method is etching the surface of the film.…”

Section: Resultsmentioning

confidence: 99%

“…Mikolajick et al reported that after the oxygen-rich surface layer of Si 3 N 4 was removed by etching in buffered HF (BHF), the pH sensitivity was increased for a certain length of time. 14) To analyze the dispersion of pH sensitivity in more detail, Fig. 9 shows a cumulative probability plot of the data shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The dispersion is attributed to the nonuniformity of various ratios of OH and NH 2 sites at the Si 3 N 4 film surface of each ISFET. In the site-binding model, the ratio = N(SiOH)/N(SiNH 2 ), affects pH sensitivity, 14,15) where N is site density. According to numerical simulation, 14,15) in the case of > 7=3, pH sensitivity tends to decrease as pH value decreases, and in < 7=3, pH sensitivity decreases with increasing pH value.…”

Section: Resultsmentioning

confidence: 99%

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Complementary Metal–Oxide–Semiconductor Ion-Sensitive Field-Effect Transistor Sensor Array with Silicon Nitride Film Formed by Catalytic Chemical Vapor Deposition as an Ion-Sensitive Membrane

Kagohashi

Ozawa

Uno

et al. 2010

Jpn. J. Appl. Phys.

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Integration of 16 Â 16 and 32 Â 32 extended-gate ion-sensitive field-effect transistor (ISFET) arrays with a low-power consumption read-out circuitry has been reported. Si 3 N 4 film used as a pH sensitive layer is deposited on the 4 Â 4 mm 2 extended-gate electrodes of ISFETs in the integrated circuit by catalytic chemical vapor deposition (Cat-CVD). The average pH sensitivity is 41 mV/pH, and the distribution obeys a Gaussian distribution with a standard deviation of 1.5 -3.4 mV. The result is compared with that of pH sensitivity measurement using an Al 2 O 3 layer formed by O 2 plasma. #

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“…It is expected from the site-binding theory that the state of the surface of the Si 3 N 4 is critical for the pH sensing properties [5]. Impurities, such as oxygen or other ions, which exist at the Si 3 N 4 surface can result in a non-ideal sensitivity [6]. Further investigation of these aspects is needed.…”

Section: Resultsmentioning

confidence: 99%

Polycrystalline Silicon ISFETs on Glass Substrate

Yan

Estrela

Yang

et al. 2005

Sensors

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Abstract:The Ion Sensitive Field Effect Transistor (ISFET) operation based on polycrystalline silicon thin film transistors is reported. These devices can be fabricated on inexpensive disposable substrates such as glass or plastics and are, therefore, promising candidates for low cost single-use intelligent multisensors. In this work we have developed an extended gate structure with PE-CVD Si 3 N 4 deposited on top of a conductor, which also provides the electrical connection to the remote TFT gate. Nearly ideal pH sensitivity (54 mV/pH) and stable operation have been achieved. Temperature effects have also been characterized. A penicillin sensor has been fabricated by functionalizing the sensing area with penicillinase. The shift increases almost linearly upon the increase of penicillin concentration until saturation is reached for ~ 7 mM. Poly-Si TFT structures with a gold sensing area have been also successfully applied to field-effect detection of DNA.

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The influence of surface oxidation on the pH-sensing properties of silicon nitride

Cited by 26 publications

References 9 publications

Nanoscale thickness double-gated field effect silicon sensors for sensitive pH detection in fluid

Nanoscale thickness double-gated field effect silicon sensors for sensitive pH detection in fluid

Complementary Metal–Oxide–Semiconductor Ion-Sensitive Field-Effect Transistor Sensor Array with Silicon Nitride Film Formed by Catalytic Chemical Vapor Deposition as an Ion-Sensitive Membrane

Polycrystalline Silicon ISFETs on Glass Substrate

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