A high sensitivity compact gas concentration sensor using UV light and charge amplifier circuit

Ishii, Hiroki; Nagase, Masaaki; Ikeda, Nobukazu; Shiba, Yoshitaka; Shirai, Yoshihito; Kuroda, Rihito; Sugawa, Shigetoshi

doi:10.1109/icsens.2016.7808698

Cited by 5 publications

(7 citation statements)

References 2 publications

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“…Ultraviolet (UV) radiation sensing has been extensively researched and applied to several fields including scientific analysis, industrial, medical, safety systems and so on [1,2,3,4]. Some examples of already reported applications are UV spectroscopy [5], UV cure process monitoring [6], solar UV measurement for healthcare applications [7], flame detection [8], semiconductor process control [9], among many others. The target wavelength for those applications are mainly in the UV-A (315 nm to 380 nm), UV-B (280 nm to 315 nm) and UV-C (200 nm to 280 nm) wavebands.…”

Section: Introductionmentioning

confidence: 99%

A Highly Robust Silicon Ultraviolet Selective Radiation Sensor Using Differential Spectral Response Method

Silva

Kuroda

Sugawa

2019

Sensors

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This paper presents a silicon ultraviolet radiation sensor with over 90% UV internal quantum efficiency (QE) and high selectivity to the UV waveband without using optical filters. The sensor was developed for applications that require UV measurement under strong background visible and near-infrared (NIR) lights, such as solar UV measurement, UV-C monitoring in greenhouses or automated factories, and so on. The developed sensor is composed of monolithically formed silicon photodiodes with different spectral sensitivities: a highly UV responsive photodiode with internal quantum efficiency (QE) of nearly 100% for UV light, and a lowly UV responsive photodiode with UV internal QE lower than 10%. The photodiodes were optimized to match their visible and NIR light responsivity, and the UV signal is extracted from the background radiation by using the differential spectral response method. With this approach, an internal QE of over 90% for UV light was obtained, with a residual internal QE to non-UV light lower than 20% for 400 nm, 5% for 500 nm, 2% for 600 nm and 0.6% to NIR light. The developed sensor showed no responsivity degradation after exposure towards strong UV light. It was confirmed by the simulation results that the residual responsivity is further suppressed by employing an on-chip band-rejection optical layer consisting of several layers of silicon oxide and silicon nitride films.

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Section: Introductionmentioning

confidence: 99%

A Highly Robust Silicon Ultraviolet Selective Radiation Sensor Using Differential Spectral Response Method

Silva

Kuroda

Sugawa

2019

Sensors

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“…On the other hand, various MO gases have relatively high light absorbance in the UV waveband. [17][18][19][20][21] Focusing on this characteristic, we have been researching the development of a high-sensitivity MO gas concentration sensor using a timesharing dual-wavelength UV light absorption method. [17][18][19] The Lambert-Beer law (Eq.…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19][20][21] Focusing on this characteristic, we have been researching the development of a high-sensitivity MO gas concentration sensor using a timesharing dual-wavelength UV light absorption method. [17][18][19] The Lambert-Beer law (Eq. 1) relates attenuation and concentration when a target gas is irradiated with light:…”

Section: Introductionmentioning

confidence: 99%

“…By using a charge amplifier circuit to integrate photo charge for a higher SN ratio, a detection limit of the order of 10 ppm has been achieved for several MO gases. 17,18) Since the concentration of TMA gas in the bubbling method is generally about 1%, the detection accuracy of the gas concentration sensor needs be 100 ppm or better. The shortest wavelength LED we used was 252 nm, but even with this we could not obtain a detection limit of more than 100 ppm.…”

Section: Introductionmentioning

confidence: 99%

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A high-sensitivity compact gas concentration sensor using ultraviolet light absorption with a heating function for a high-precision trimethyl aluminum gas supply system

Ishii

Nagase

Ikeda

et al. 2019

Jpn. J. Appl. Phys.

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This work presents a high-sensitivity, real-time, compact gas concentration sensor using a time-sharing dual-wavelength UV light absorption method developed for a high-precision trimethyl aluminum (TMA) gas supply system. We analyzed the characteristics of TMA, examined a method to increase sensitivity by controlling the gas transition, and fabricated a highly reliable heatable gas cell. The detection circuit demonstrated that TMA can be measured stably using a charge amplifier method that can detect various metal organic gases with high sensitivity. By controlling the sensing temperature to increase the ratio of TMA monomers (which have a higher UV absorbance) to dimers, a detection limit of 62.7 ppm was achieved.

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“…Those applications are known to have different requirements than the conventional applications of imaging for viewing and entertainment. For instance, among the wavebands outside the visible light spectrum, the ultraviolet (UV) waveband (200-400 nm) has already been reported to contain useful information for data acquisition, such as: detection of harmful substances [6], measurement of ozone concentration in ozonated water [7], gas concentration measurement in semiconductor processes chambers [8], flame detection [9], and so on [10][11][12][13]. As research continues for the development of new applications, there is an increasing demand for image sensors with high UV sensitivity, high selectivity of sensitivity to the UV waveband, and an easy manufacturing process for low cost.…”

Section: Introductionmentioning

confidence: 99%

An Optical Filter-Less CMOS Image Sensor with Differential Spectral Response Pixels for Simultaneous UV-Selective and Visible Imaging

Silva

Kuroda

Sugawa

2019

Sensors

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This paper presents a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) capable of capturing UV-selective and visible light images simultaneously by a single exposure and without employing optical filters, suitable for applications that require simultaneous UV and visible light imaging, or UV imaging in variable light environment. The developed CIS is composed by high and low UV sensitivity pixel types, arranged alternately in a checker pattern. Both pixel types were designed to have matching sensitivities for non-UV light. The UV-selective image is captured by extracting the differential spectral response between adjacent pixels, while the visible light image is captured simultaneously by the low UV sensitivity pixels. Also, to achieve high conversion gain and wide dynamic range simultaneously, the lateral overflow integration capacitor (LOFIC) technology was introduced in both pixel types. The developed CIS has a pixel pitch of 5.6 µm and exhibits 172 µV/e − conversion gain, 131 ke − full well capacity (FWC), and 92.3 dB dynamic range. The spectral sensitivity ranges of the high and low UV sensitivity pixels are of 200-750 nm and 390-750 nm, respectively. The resulting sensitivity range after the differential spectral response extraction is of 200-480 nm. This paper presents details regarding the CIS pixels structures, doping profiles, device simulations, and the measurement results for photoelectric response and spectral sensitivity for both pixel types. Also, sample images of UV-selective and visible spectral imaging using the developed CIS are presented.

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A high sensitivity compact gas concentration sensor using UV light and charge amplifier circuit

Cited by 5 publications

References 2 publications

A Highly Robust Silicon Ultraviolet Selective Radiation Sensor Using Differential Spectral Response Method

A Highly Robust Silicon Ultraviolet Selective Radiation Sensor Using Differential Spectral Response Method

A high-sensitivity compact gas concentration sensor using ultraviolet light absorption with a heating function for a high-precision trimethyl aluminum gas supply system

An Optical Filter-Less CMOS Image Sensor with Differential Spectral Response Pixels for Simultaneous UV-Selective and Visible Imaging

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