Surface-micromachined pyroelectric infrared imaging array with vertically integrated signal processing circuitry

Pham, Linda; Tjhen, W.; Ye, C.; Polla, Dennis L.

doi:10.1109/58.294117

Cited by 29 publications

(13 citation statements)

References 9 publications

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“…When the sensor is applied in the focal plane arrays of thermal imaging systems, the NETD characterizes the minimum temperature variation across a scene or an object that the sensor can detect, and is given as (7) where is the focal length of the optics, is the transmittance of the optics, and is the change with temperature of the power density from a black body at temperature radiated to a detector from wavelength to . To calculate the NETD, we assumed that the measurement was carried out at 296 K in the IR spectrum of [8][9][10][11][12][13][14] where is about 2.63 , and optics were used with . The NETD of the sensor was calculated to be 68 mK for and 81 mK for , which indicated the sensor had sufficient temperature resolution for the high-performance IR imaging.…”

Section: Resultsmentioning

confidence: 99%

“…For certain spectral bands in the region of [8][9][10][11][12][13][14] , no additional material for enhancing IR absorption is needed, since the SiON passivation layer has good IR absorptions due to Si-O bonds (8-10 ) and Si-N bonds (11)(12)(13). Numerical calculations show an absorptivity of over 60% can be reached in the [8][9][10][11][12][13][14] band. In this design, each pixel has an area of 150 90 , and the a-Si TFT has a ratio of channel width to length (W/L) of 100 /8 .…”

Section: Pixel Structure and Array Circuitmentioning

confidence: 99%

“…They usually show a relatively flat response over a wide range of wavelengths and are sensitive up to wavelengths longer than 100 . There are several kinds of available uncooled IR sensors such as resistive or dielectric microbolometers [1]- [7], pyroelectric detectors [8]- [11], and thermopiles [12]- [14]. In essence, all these sensors consist of a two-dimension array of thermosensitive pixels, whose temperature is increased by the impinging IR radiation.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

Yue

Liu

2005

J. Microelectromech. Syst.

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In this paper, we report on the first realization and characterization of monolithic uncooled 8 8 infrared sensor arrays, based on amorphous silicon thin-film transistors (a-Si TFT). The a-Si TFT is employed as the active element of the sensor, because it possesses a high temperature coefficient of its drain current of 1.5%-6.5% K 1 at room temperature. The improved porous silicon micromachining techniques described here enable the integration of the a-Si TFT-based sensor array with the MOS readout circuitry. The sacrificial material of porous silicon is prepared in the first step. It is then well protected all the time during the fabrication of MOSFETs and sensors before being released. Optical tests are performed to characterize the sensor. The influences of the gate voltage of a-Si TFT ( ) and the voltage source of the circuitry ( ) on the sensor performance are investigated. The measurement indicates that the sensor has a maximum detectivity of 8.67 10 8 cm Hz 1 2 W 1 at = 15 V, = 12 V and a chopping frequency of 30 Hz. The noise equivalent power (NEP) of the sensor is less than 10 10 W Hz 1 2 , and the noise equivalent temperature difference (NETD) is as low as 67 mK at room temperature, which compares well with the recent results of some uncooled IR sensors developed by other groups. Primary imaging tests indicate that the 8 8 sensor array has potential for high performance imaging applications.[1168]

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Section: Resultsmentioning

confidence: 99%

Section: Pixel Structure and Array Circuitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

Yue

Liu

2005

J. Microelectromech. Syst.

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“…In contrast, uncooled IR detectors based on the application of perovskite oxide ferroelectric materials are of significant importance due to their ability to provide economical pyroelectric detectors and thermal imaging devices; attributed to their ability to be used successfully at ambient temperatures, thereby eliminating the need for expensive cooling systems [2]. The majority of pyroelectric sensors have been based on bulk perovskite oxide materials such as BST (barium strontium titanate, BaSrTiO 3 ), PbTiO 3 (lead titanate, PT), (Pb,La)TiO 3 (lead lanthanate titanate, PLT) and Pb(Zr,Ti)O 3 (lead zirconate titanate, PZT) bulk ceramics [3][4][5], and LiTiO 3 single crystals [6] and the pyroelectric vidicon has been developed. Perovskite oxide-ferroelectric ceramic materials possess a number of properties, which make them very important for use in pyroelectric sensors/detectors.…”

Section: Introductionmentioning

confidence: 99%

MATERIAL PROPERTIES OF MOSD DERIVED Ba_{1 -x}Sr_xTiO₃-BASED THIN FILMS FOR PYROELECTRIC SENSOR APPLICATIONS

Cole

Joshi²,

Hubbard

et al. 2006

Integrated Ferroelectrics

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BaSrTiO 3 (BST) thin films with a nominal composition of Ba 0.60 Sr 0.40 TiO 3 and BST thin films doped with magnesium, aluminum, lanthanum and tantalum (0-20.0 mol% for Mg and 1.0 mol% for the Al, La and Ta dopants) were synthesized via the metalorganic solution deposition (MOSD) technique in order to investigate their potential for use as the active material in uncooled infrared (IR) detector applications. The films were characterized for structural, microstructural, compositional, surface morphological, dielectric and insulating properties. The Materials Detectivity Figure of Merit (FOM), D * , [D * = pi /(C V (ε 0 ε r tan δ) 1/2 ] was used to evaluate the film's detectivity response. Our results suggest that undoped Ba 60 Sr 40 TiO 3 , with a value of D * = 0.08 (cm 3 /J) 1/2 , appears to out perform Pb based pyroelectric thin films, thus making it a viable candidate for IR pyroelectric detector applications. In addition the preliminary dielectric response studies of the 5 mol% Mg doped BST and 1 mol% La doped BST thin films indicate that these two materials are also excellent potential IR material candidates.

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“…INTRODUCTION Detectors, which respond to radiant energy can be classified into two broad categories: photon detectors and thermal detectors [1]. In the photon detectors, absorbed photon excites electrons to higher energy level resulting photoelectric effect.…”

mentioning

confidence: 99%

Thermal modeling of novel monolithic pyroelectric infrared image sensors

Matin

Sugai

Kawazu

et al. 2010

2010 12th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

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In this paper, we present designing, fabrication and thermal simulation of smart 1024-element (32x32) monolithic pyroelectric infrared image sensors. A sol-gel deposited PZT(001) thin film was used as a pyroelectric material. We tailored the geometries and dimensions of devices in designing smart image sensors. The influence of thermal isolator has shown to significantly reduce the heat loss to the device structure and environment. Introducing circular type pixels instead of rectangular type ones, has confirmed to obtain an optimal design of smart image sensor, with the maximal temperature change of 4 mK at a response frequency of 10Hz. KEY WORDS: thermal modeling, pyroelectric image sensor, micromachining, thin-film, sol-gel, monolithic, epitaxial. NOMENCLATURE A area, m 2 H heat capacity, J K -1 C volumetric heat capacity, J m -3 K -1 D electric displacement field, C m -2 D * normalized detectivity, m Hz 1/2 W -1 E electric field, V/m f frequency, s -1 G thermal conductance, W k -1 l thickness, m P incident IR radiant power, W p pyroelectric coefficient, C m -2 k -1 R sensitivity, V/W t time, s T temperature, K ∆Τ temperature rise, K Greek symbols ω angular frequency (s -1 ) ε dielectric constant (F m -1 ) η IR absorbance (-) τ thermal time constant (m s kg -1 ) ρ mass density (kg m -3 ) ℜ specific current response (A W -1 ) Ψ constant (-) þ polarization, C m -2

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Surface-micromachined pyroelectric infrared imaging array with vertically integrated signal processing circuitry

Cited by 29 publications

References 9 publications

Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

MATERIAL PROPERTIES OF MOSD DERIVED Ba_{1 -x}Sr_xTiO₃-BASED THIN FILMS FOR PYROELECTRIC SENSOR APPLICATIONS

Thermal modeling of novel monolithic pyroelectric infrared image sensors

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Surface-micromachined pyroelectric infrared imaging array with vertically integrated signal processing circuitry

Cited by 29 publications

References 9 publications

Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

Fabrication and characterization of integrated uncooled infrared sensor arrays using a-Si thin-film transistors as active elements

MATERIAL PROPERTIES OF MOSD DERIVED Ba1 -xSrxTiO3-BASED THIN FILMS FOR PYROELECTRIC SENSOR APPLICATIONS

Thermal modeling of novel monolithic pyroelectric infrared image sensors

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MATERIAL PROPERTIES OF MOSD DERIVED Ba_{1 -x}Sr_xTiO₃-BASED THIN FILMS FOR PYROELECTRIC SENSOR APPLICATIONS