• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.35.2-35.2
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• 2008

The Albedo MONitor and RAdiometer (AMON-RA) instrument system is designed to measure Earth global albedo anomaly over the wavelength range of 0.3um to 4um. The instrument consists of two interconnecting optical subsystems i.e. a visible channel and an energy channel. The energy channel instrument consists of a modified Winston cone, a couple of relay mirrors and a pyro-electric detector. First, we report the integration and alignment process, leading to the prototype bolometer instrument. We then discuss the radiometric performance characterization including laboratory measurement results and the future plan for further incorporation of the bolometer instrument into the prototype AMON-RA instrument.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.28.4-29
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• 2009

The 'Amon-Ra' instrument of the proposed 'EARTHSHINE' satellite is a dual (i.e. imaging and energy) channel instrument for monitoring the total solar irradiance (TSI) and the Earth's irradiance at around the L1 halo orbit. Earlier studies for this instrument include, but not limited to, design and construction of breadboard Amon-Ra imaging channel, stray light suppression and system performance computation using Integrated Ray Tracing (IRT) technique. The Amon-Ra instrument is required to produce 0.3% in uncertainty for both Sunlight and Earthlight measurement. In this study, we report accurate estimation of the output electric signal derived from the orbital variation of radiant exitance from the Sun and the Earth arriving at the aperture and detector plane of the Amon-Ra. For this, orbital irradiance are computed analytically first and then confirmed by simulation using Integrated Ray Tracing (IRT) model. Specially, the results show the arriving power at the bolometer detector surface is $1.24{\mu}W$ for the Sunlight and $1.28{\mu}W$ for the Earthlight, producing the output signal pulses of 34.31 mV and 35.47 mV respectively. These results demonstrate successfully that the arriving radiative power is well within the bolometer detector dynamic range and, therefore, the proposed detector can be used for the in-orbit measurement sequence. We discuss the computational details and implications as well as the simulation results.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.379-384
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• 2015

An infrared image sensor is a core device in a thermal imaging system. The fabrication method of a focal plane array (FPA) is a key technology for a high resolution infrared image sensor. Each pixels in the FPA have $Si_3N_4/SiO_2$ membranes including legs to deposit bolometric materials and electrodes on Si readout circuits (ROIC). Instead of polyimide used to form a sacrificial layer, the feasibility of an amorphous silicon (${\alpha}-Si$) was verified experimentally in a $8{\times}8$ micro-bolometer array with a $50{\mu}m$ pitch. The elimination of the polyimide sacrificial layer hardened by a following plasma assisted deposition process is sometimes far from perfect, and thus requires longer plasma ashing times leading to the deformation of the membrane and leg. Since the amorphous Si could be removed in $XeF_2$ gas at room temperature, however, the fabricated micro-bolomertic structure was not damaged seriously. A radio frequency (RF) sputtered nickel oxide film was grown on a $Si_3N_4/SiO_2$ membrane fabricated using a low stress silicon nitride (LSSiN) technology with a LPCVD system. The deformation of the membrane was effectively reduced by a combining the ${\alpha}-Si$ and LSSiN process for a nickel oxide micro-bolometer.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.178-183
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• 2015

Optical, electrical and structural properties of VOx/ZnO/VOx thin film are studied. The VOx/ZnO/VOx multilayer is deposited by using a radio frequency (RF) sputtering system. The VOx/ZnO/VOx thin film shows the high temperature coefficient of resistance (TCR) of $-3.12%/^{\circ}C$ and the low sheet resistance of about 80 $k{\Omega}/sq$ at room temperature. The responsivity and detectivity of the bolometer are measured as a function of modulation frequency.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.154.1-154.1
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• 2016

ITER 내부 플라즈마 진단에 대한 연구는 활발히 이루어지고 있다. 그 중에서도 광학 시스템을 이용한 진단방법으로 OES, Bolometer, Stark effects, Thomson scattering이 주로 연구되고 있다. 이러한 방법을 구현하기 위해서는 핵융합로 내부에 first mirror 설치가 필수적이다. 그러나 노 내부에서 발생한 플라즈마에 의한 부식과 증착 및 광 소스에 의한 first mirror 표면 손상이 현재 ITER 주요 난제중 하나로 꼽히고 있다. 이는 추후 건설될 DEMO와 핵융합로 건설을 위해서도 필요한 연구이다. 그러나 국내에서는 이러한 연구가 거의 진행되고 있지 않다. 이에 따라 Thomson scattering 진단계와 first mirror 관련 연구동향을 추적하였다. 그리고 이 추적한 결과를 바탕으로 감마선환경에서 first mirror의 특성을 분석했다. 또한 오염 제거 및 방지를 위하여 TE(thermos-electric) 시스템을 제작하고 있다. 그리고 high energy neutral beam에 대한 플라즈마를 이용한 오염방지 실험을 진행하고 있다.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.91-95
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• 2017

Recently, infrared (IR) spectrometers have been required in various fields such as environment, safety, mobile, automotive, and military. This IR dispersive sensor detection method of substances is widely used. In this study, we fabricated a silicon (Si) prism-based near infrared (NIR) spectrometer utilizing micro electro mechanical system (MEMS) technology. Si prism-based NIR spectrometer utilizing MEMS technology consists of upper, middle, and lower substrates. The upper substrate passes through the incident IR ray selectively. The middle substrate, acting as a prism, disperses and separates the incident IR beam. The lower substrate has an amorphous Si (a-Si)-based bolometer array to detect the IR spectrum. The fabricated Si prism-based NIR spectrometer utilizing MEMS technology has the advantage of a simple structure, easy fabrication steps, and a wide NIR region operating range.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.201-201
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• 2010

볼로미터 제작 공정 중 One step via 공정 시 via hole 모양에 의해 정기적 연결 및 구조적 안정성에 문제를 해결하기 위하여 다른 via 식각 방식으로 공정을 진행하였으며 그에 따른 via 공정 차이에 대한 결과를 연구하였다.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.130-136
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• 2010

The microbolometer array sensor with fine pitch pixel array has been implemented to the released amorphous silicon layer supported by two contact pads. For the design of focal plane mirror with geometrical flatness, the simple beam test structures were fabricated and characterized. As the beam length decreased, the effect of beam width on the bending was minimized, Mirror deformation of focal plane in a real pixel showed downward curvature by residual stress of a-Si and Ti layer. The mirror tilting was caused by the mis-align effect of contact pad and confirmed by FEA simulation results. The properties of bolometer have been measured as such that the NETD 145 mK, the TCR -2 %/K, and thermal time constant 1.99 ms.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.38.1-38.1
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• 2010

We present the results of the survey for submillimeter galaxies in the MS0451 (04h 54m 10.8s, -03d 00m 57.0s) at z = 0.55 and PKS1138-262 (11h 40m 48.25s, -26d 29m 10.1s) at z = 2.16 with the 1.1mm bolometer array AzTEC at the James Clerk Maxwell Telescope. The samples were centered on a prominent large-scale structure overdensity. Submillimeter galaxies seem to be starburst galaxies at high redshift ($z\;\geq\;1$) with high starformation rates ($\sim1000M\odot\;yr^{-1}$) or active galactic nuclei (AGN). We have obtained AzTEC images using the AzTEC data reduction pipeline with the IDL language. Through a bayes' theorem, we determined the extragalaxy catalogue, containing the false-detection rate, completeness, flux deboosting correction, and the source positional uncertainty in this region. We compared the catalogue with HST, DSS, 2MASS observations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.391-392
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• 2008

A surface micromachined uncooled microbolometer based on the amorphous silicon was designed and fabricated. We designed the microbolometer with a pixel size of $35\times35$, $44\times44{\mu}m^2$ and a fill factor of about 70 % by considering such important factors as the thermal conductance, thermal time constant, the temperature coefficient of resistance, and device resistance. Finally, we successfully fabricated the microbolometer by using surface MEMS technology, and the properties of bolometer have been measured as such that TCR and absorptance can be achieved above -2.5%/K and about 90% with titanium layer, respectively.