Status of Uncooled Infrared Detector Technology at ULIS, France

Tissot, Jean-Luc; Robert, P. C.; Durand, A.; Tinnes, S.; Bercier, Emmanuel; Crastes, A.

doi:10.14429/dsj.63.5753

Cited by 13 publications

(6 citation statements)

References 6 publications

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“…In microbolometers, the main features of the thermo-sensing materials are the high value of the TCR (α), moderate resistivity, low noise, and compatibility with the fabrication processes of silicon IC [6,7]. Two main semiconductor materials are used in commercial microbolometers: vanadium oxide and amorphous silicon [8,9]. Vanadium oxide and amorphous silicon lms can achieve high temperature coe cients of resistances and their synthesis process is CMOS compatible [10,11].…”

Section: Introductionmentioning

confidence: 99%

Electro-Optical Characterization of an Amorphous Germanium-Tin (Ge1-XSnx) Microbolometer

Bahaidra

Al‐Khalli

Hezam

et al. 2023

J Infrared Milli Terahz Waves

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The utilization of amorphous germanium-tin (Ge 1 − x Sn x ) semiconducting thin lms as temperature sensing layers in microbolometers was recently presented and patented. The work in this paper started by extending the latest study to acquire better characteristics of the Sn concentrations % for microbolometer applications. In this work, Ge1-xSnx thin lms with various Sn concentrations %, x, where 0.31 ≤ x ≤ 0.48 we sputter deposited. Elemental composition was evaluated using Energy Dispersive X-ray (EDX) spectroscopy. Surface morphology was evaluated using Atomic Force Microscopy (AFM) revealing average roughness values between ~ 0.2-0.8 nm. Sheet resistance versus temperature measurements was performed and analyzed revealing temperature coe cients of resistances, TCRs, ranging from − 3.11%/K to -2.52%/K for x ranging from 0.31 to 0.40. The Ge1-xSnx thin lm was found to depart the semiconducting behavior at 0.40 < x ≤ 0.48. Empirical relationships are derived relating resistivity, TCR, and Sn concentration % for amorphous Ge1-xSnx thin lms. One of the lms with 31% Sn concentration (Ge 0.69 Sn 0.31 ) was used to fabricate 10×10 µm2 microbolometer prototypes using electron-beam lithography and liftoff techniques and the microbolometer is fabricated on top of oxidized silicon substrates with no air gap between them. The noise behavior and the maximum detected signal of the fabricated microbolometer were measured. The signal-to-noise ratio, voltage responsivity, and noise equivalent power values of the prototypes were calculated. Finally, the expected performance of the microbolometer when fabricated in an air bridge is calculated.

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Section: Introductionmentioning

confidence: 99%

Electro-Optical Characterization of an Amorphous Germanium-Tin (Ge1-XSnx) Microbolometer

Bahaidra

Al‐Khalli

Hezam

et al. 2023

J Infrared Milli Terahz Waves

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“…There are several vacuum packaging methods reported including die level packaging [13][14][15][16] and wafer level packaging [17][18][19][20][21][22]. There are also efforts to make pixel level vacuum packaging where the packaging process is the part of detector fabrication process [23][24][25][26][27][28][29][30][31][32]. By this method, the need for expensive packaging equipment like a wafer bonder can be eliminated.…”

Section: Introductionmentioning

confidence: 99%

Pixel level vacuum packaging for single layer microbolometer detectors with on pixel lens

Tanrikulu

2022

Journal of Electrical Engineering

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This paper presents a new approach for fabrication of single layer microbolometer detectors featuring pixel level vacuum packaging together with a lens on the pixel. The proposed lens structure can be used to increase the fill factor of the detector so that the pixel size can be decreased without decreasing the minimum feature size in the detector which is a problem in single layer microbolometers. The designs of the lens and the fabrication process of pixel level vacuum packaged microbolometer detector together with this lens are given in the framework of this study. The optical and mechanical simulations of the structure are performed. The radius of curvature of the lens is optimized to be 25 μm and it is shown that the condensing efficiency is 100% for 3 μm lens-detector distance. The deflection in the lens structure is found approximately as 0.8 nm in 1 atm environment pressure, showing that the proposed structure is durable. The proposed structure increases the fill factor to twice of the original value without decreasing the minimum feature size in the fabrication processes, resulting in the same amount of improvement in the performance of the detector. This approach can also be used to increase the yield and decrease the fabrication cost of single layer and also standard microbolometers with small pixel sizes, as it integrates the vacuum packaging in the fabrication steps.

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“…At the present time, vanadium oxide (VO x ) (~2%/K) [10][11][12][13][14][15][16] and doped amorphous silicon (a-Si) with TCR values of 2%-5%/K [17][18][19][20][21][22] are the two main materials used as thermosensing films in commercial microbolometers. However, amorphous silicon, usually doped with boron, is replacing vanadium oxide in large commercial arrays.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Microbolometer Arrays Based on Polymorphous Silicon–Germanium

Jiménez

Moreno

Torres

et al. 2020

Sensors

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This work reports the development of arrays of infrared sensors (microbolometers) using a hydrogenated polymorphous silicon–germanium alloy (pm-SixGe1-x:H). Basically, polymorphous semiconductors consist of an amorphous semiconductor matrix with embedded nanocrystals of about 2–3 nm. The pm-SixGe1-x:H alloy studied has a high temperature coefficient of resistance (TCR) of 4.08%/K and conductivity of 1.5 × 10−5 S∙cm−1. Deposition of thermosensing film was made by plasma-enhanced chemical vapor deposition (PECVD) at 200 °C, while the area of the devices is 50 × 50 μm2 with a fill factor of 81%. Finally, an array of 19 × 20 microbolometers was packaged for electrical characterization. Voltage responsivity values were obtained in the range of 4 × 104 V/W and detectivity around 2 × 107 cm∙Hz1/2/W with a polarization current of 70 μA at a chopper frequency of 30 Hz. A minimum value of 2 × 10−10 W/Hz1/2 noise equivalent power was obtained at room temperature. In addition, it was found that all the tested devices responded to incident infrared radiation, proving that the structure and mechanical stability are excellent.

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Status of Uncooled Infrared Detector Technology at ULIS, France

Cited by 13 publications

References 6 publications

Electro-Optical Characterization of an Amorphous Germanium-Tin (Ge1-XSnx) Microbolometer

Electro-Optical Characterization of an Amorphous Germanium-Tin (Ge1-XSnx) Microbolometer

Pixel level vacuum packaging for single layer microbolometer detectors with on pixel lens

Fabrication of Microbolometer Arrays Based on Polymorphous Silicon–Germanium

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