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1.
Johan Rothman Laurent Mollard Sylvie Bosson Gautier Vojetta Kevin Foubert Sylvain Gatti Gwladys Bonnouvrier Frederic Salveti Alexandre Kerlain Olivier Pacaud 《Journal of Electronic Materials》2012,41(10):2928-2936
Short-wave infrared (SWIR) HgCdTe avalanche photodiodes (APDs) have been developed to address low-flux applications at low operating temperature and for laser detection at higher temperatures. Stable multiplication gains in excess of 200 have been observed in homojunction APDs with cutoff wavelengths down to 2.8???m and operating temperatures up to 300?K, associated with low excess noise F?<?1.3 and low 1/f noise. The measured dark current density at 200?K of 6.2???A/cm2 is low enough to enable high-sensitivity single-element light detection and ranging (lidar) applications and time-of-flight imaging. Corresponding APD arrays have been hybridized on a readout integrated circuit (ROIC) designed for low-flux low-SNR imaging with low noise and frame rates higher than 1500?frames/s. Preliminary focal-plane array characterization has confirmed the nominal ROIC performance and showed pixel operability above 99.5% (pixels within ±50% of average gain). The bias dependence of the multiplication gain has been characterized as a function of temperature, cadmium composition, and junction geometry. A qualitative change in the bias dependence of the gain compared with mid-wave infrared (MWIR) HgCdTe has motivated the development of a modified local electric field model for the electron impaction ionization coefficient and multiplication gain. This model gives a close fit to the gain curves in both SWIR and MWIR APDs at temperatures between 80?K and 300?K, using two parameters that scale as a function of the energy gap and temperature. This property opens the path to quantitative predictive device simulations and to estimations of the junction geometry of APDs from the bias dependence of the gain. 相似文献
2.
HgCdTe electron avalanche photodiodes 总被引:1,自引:0,他引:1
M. A. Kinch J. D. Beck C. -F. Wan F. Ma J. Campbell 《Journal of Electronic Materials》2004,33(6):630-639
Exponential-gain values well in excess of 1,000 have been obtained in HgCdTe high-density, vertically integrated photodiode
(HDVIP) avalanche photodiodes (APDs) with essentially zero excess noise. This phenomenon has been observed at temperatures
in the range of 77–260 K for a variety of cutoff wavelengths in the mid-wavelength infrared (MWIR) band, with evidence of
similar behavior in other IR bands. A theory for electron avalanche multiplication has been developed using density of states
and electron-interaction matrix elements associated with the unique band structure of HgCdTe, with allowances being made for
the relevant scattering mechanisms of both electrons and holes at these temperatures. This theory is used to develop an empirical
model to fit the experimental data obtained at DRS Infrared Technologies. The functional dependence of gain on applied bias
voltage is obtained by the use of one adjustable parameter relating electron energy to applied voltage. A more quantitative
physical theory requires the use of Monte Carlo techniques incorporating the preceding scattering rates and ionization probabilities.
This has been performed at the University of Texas at Austin, and preliminary data indicate good agreement with DRS models
for both avalanche gain and excess noise as a function of applied bias. These data are discussed with a view to applications
at a variety of wavelengths. 相似文献
3.
A. Sieck M. Benecke D. Eich R. Oelmaier J. Wendler H. Figgemeier 《Journal of Electronic Materials》2018,47(10):5705-5714
Short-wave infrared (SWIR) HgCdTe electron avalanche photodiodes (eAPDs) with different doping profiles have been characterized for use in SWIR gated viewing systems. Gated viewing offers enhanced image contrast in scenes with clutter from the foreground or background. HgCdTe-based eAPDs show exponential gain–voltage characteristics and low excess noise and are, therefore, well suited for active imaging applications. The gain achievable at a fixed reverse voltage varies with the bandgap of the Hg1?xCdxTe detector material. We analyze current–voltage and gain–voltage plots measured on SWIR Hg1?xCdxTe eAPDs with x?=?0.45, corresponding to a cutoff wavelength of 2.55 μm at 150 K. The cutoff has been chosen as a trade-off between achievable APD gain and operating temperature for SWIR gated-viewing systems with target distances of about 1000 m. Focal plane arrays with a readout-integrated circuit featuring a fast internal clock have been built and their performance with respect to gated viewing applications has been evaluated on a laboratory demonstrator for short distances. Future plans for a field demonstrator for distances up to 1000 m are described briefly at the end. 相似文献
4.
Jeffrey Beck Richard Scritchfield Billy Sullivan Jamie Teherani Chang-Feng Wan Mike Kinch Martha Ohlson Mark Skokan Lewis Wood Pradip Mitra Mike Goodwin Jim Robinson 《Journal of Electronic Materials》2009,38(8):1579-1592
The operation of the mid-wave infrared (MWIR) HgCdTe cylindrical electron injection avalanche photodiode (e-APD) is described.
The measured gain and excess noise factor are related to the collection region fill factor. A two-dimensional diffusion model
calculates the time-dependent response and steady-state pixel point spread function for cylindrical diodes, and predicts bandwidths
near 1 GHz for small geometries. A 2 μm diameter spot scan system was developed for point spread function and crosstalk measurements at 80 K. An electron diffusion
length of 13.4 μm was extracted from spot scan data. Bandwidth data are shown that indicate bandwidths in excess of 300 MHz for small unit
cells geometries. Dark current data, at high gain levels, indicate an effective gain normalized dark density count as low
as 1000 counts/μs/cm2 at an APD gain of 444. A junction doping profile was determined from capacitance–voltage data. Spectral response data shows
a gain-independent characteristic. 相似文献
5.
Jeff Beck Milton Woodall Richard Scritchfield Martha Ohlson Lewis Wood Pradip Mitra Jim Robinson 《Journal of Electronic Materials》2008,37(9):1334-1343
The next generation of infrared (IR) sensor systems will include active imaging capabilities. One example of such a system
is a gated active/passive system. The gated active/passive system promises target detection and identification at longer ranges
compared to conventional passive-only imaging systems. A detector that is capable of both active and passive modes of operation
opens up the possibility of a self-aligned system that uses a single focal plane. The mid-wave infrared (MWIR) HgCdTe electron
injection avalanche photodiode (e-APD) provides state-of-the-art 3 μm to 5 μm performance for the passive mode and high, low-noise, gain in the active mode, and high quantum efficiency at 1.5 μm. Gains of greater than 1000 have been measured in MWIR e-APDs with a gain-independent excess noise factor of 1.3. This paper
reports the application of the mid-wave HgCdTe e-APD for near-IR gated-active/passive imaging. Specifically a 128 × 128 focal-plane
array (FPA) composed of 40-μm-pitch MWIR cutoff APD detectors and custom readout integrated circuit was designed, fabricated, and tested. Median gains
as high as 946 at 11 V bias with noise equivalent photon inputs as low as 0.4 photon were measured at 80 K and 1 μs gate times. This subphoton sensitivity is consistent with the high gains, low excess noise factor, and low effective gain
normalized dark-current densities, near or below 1 nA/cm2, that were achieved in these FPAs. A gated imaging demonstration system was designed and built using commercially available
parts. High resolution and precision gating was demonstrated in this system by imagery taken at ranges out to 9 km. 相似文献
6.
S. Derelle S. Bernhardt R. Haidar J. Deschamps J. Primot J. Rothman S. Rommeluere N. Guérineau 《Journal of Electronic Materials》2009,38(8):1628-1636
We evaluated the performance of long-wavelength infrared (LWIR, λ
c = 9.0 μm at 80 K) mercury cadmium telluride electron-injected avalanche photodiodes (e-APDs) in terms of gain, excess noise factor,
and dark current, and also spectral and spatial response at zero bias. We found an exponential gain curve up to 23 at 100 K
and a low excess noise factor close to unity (F = 1–1.25). These properties are indicative of a single carrier multiplication process, which is electron impact ionization.
The dark current is prevailed by a diffusion current at low reverse bias. However, tunneling currents at higher reverse bias
limited the usable gain. The measurements of the pixel spatial response showed that the collection width, and, especially,
the amplitude of the response peak, increased with temperature. Furthermore, we developed a Monte Carlo model to understand
the multiplication process in HgCdTe APDs. The first simulation results corroborated experimental measurements of gain and
excess noise factor in mid-wavelength infrared (MWIR, x = 0.3) and LWIR (x = 0.235) e-APDs at 80 K. This model makes it possible for phenomenological studies to be performed to identify the main physical
effects and technological parameters that influence the gain and excess noise. The study of the effect of the n
−-layer thickness on APD performance demonstrated the existence of an optimum value in terms of gain. 相似文献
7.
J. B. Varesi A. A. Buell R. E. Bornfreund W. A. Radford J. M. Peterson K. D. Maranowski S. M. Johnson D. F. King 《Journal of Electronic Materials》2002,31(7):815-821
We are continuing to develop our growth and processing capabilities for HgCdTe grown on 4-in. Si substrates by molecular beam
epitaxy (MBE). Both short-wave and mid-wave infrared (SWIR and MWIR) double-layer hetero-junctions (DLHJs) have been fabricated.
In order to improve the producibility of the material, we have implemented an in-situ growth composition-control system. We
have explored dry etching the HgCdTe/Si wafers and seen promising results. No induced damage was observed in these samples.
Detector results show that the HgCdTe/Si devices are state-of-the-art, following the diffusion-limited trend line established
by other HgCdTe technologies. Focal-plane array (FPA) testing has been performed in order to assess the material over large
areas. The FPA configurations range from 128×128 to 1,024×1,024, with unit cells as small as 20 μm. The MWIR responsivity
and NEDT values are comparable to those of existing InSb FPAs. Pixel operabilities well in excess of 99% have been measured.
We have also explored the role of growth macrodefects on diode performance and related their impact to FPA operability. The
SWIR HgCdTe/Si shows similar results to the MWIR material. Short-wave IR FPA, median dark-current values of less than 0.1
e−/sec have been achieved. 相似文献
8.
Low-Noise Mid-Wavelength Infrared Avalanche Photodiodes 总被引:1,自引:0,他引:1
Siddhartha Ghosh Shubhrangshu Mallick Koushik Banerjee Christoph Grein Silviu Velicu Jun Zhao Don Silversmith Jean Baptist Rodriguez Elena Plis Sanjay Krishna 《Journal of Electronic Materials》2008,37(12):1764-1769
Mid-wavelength infrared (MWIR) p
+–n
−–n
+ avalanche photodiodes (APDs) were fabricated using two materials systems, one with mercury cadmium telluride (HgCdTe) on
a silicon (Si) substrate and the other with an indium arsenide/gallium antimonide (InAs/GaSb) strained layer superlattice
(SLS). Diode characteristics, avalanche characteristics, and excess noise factors were measured for both sets of devices.
Maximum zero-bias resistance times active area (R
0
A) of 3 × 106 Ω cm2 and 1.1 × 106 Ω cm2 and maximum multiplication gains of 1250 at −10 V and 1800 at −20 V were measured for the HgCdTe and the SLS, respectively,
at 77 K. Gains reduce to 200 in either case at 120 K. Excess noise factors were almost constant with increasing gain and were
measured in the range of 1 to 1.2. 相似文献
9.
Francesco Bertazzi Michele Moresco Michele Penna Michele Goano Enrico Bellotti 《Journal of Electronic Materials》2010,39(7):912-917
A full-band Monte Carlo model has been developed for understanding the carrier multiplication process in HgCdTe infrared avalanche
photodiodes. The proposed model is based on a realistic electronic structure obtained by pseudopotential calculations and
a phonon dispersion relation determined by ab initio techniques. The calculated carrier–phonon scattering rates are consistent with the electronic structure and the phonon dispersion
relation, thus removing adjustable parameters such as deformation potential coefficients. The computation of the impact ionization
transition rate is based on the calculated electronic structure and the corresponding wavevector-dependent dielectric function.
The Monte Carlo model is applied to investigate key performance figures of long-wavelength infrared (LWIR) and mid-wavelength
infrared (MWIR) HgCdTe avalanche photodetectors such as carrier multiplication and noise properties. Good agreement is achieved
between simulations and experimental results. The multiplication process in LWIR (λ
c = 9.0 μm at 80 K) and MWIR (λ
c = 5.1 μm at 80 K) devices is found to be initiated only by electrons, as expected from excess noise measurements. This single-carrier
multiplication behavior can be traced back to the details of the computed valence-band structure and phonon scattering rates. 相似文献
10.
单光子计数技术在弱信号探测和时间测距中具有重大的应用前景。自从20世纪70年代可见光的光子计数系统研发以来,国际上该领域内的研发小组在不断地发展完善光子计数技术,充分放大光子信号,以降低电子设备的读出噪声。电子倍增电荷耦合器件(Electron Multiplying Charge Coupled Devices, EMCCDs)具有更高的量子效率,可替代传统的可见光光子计数系统,但较大的雪崩噪声阻碍了倍增下入射光子数的准确获取。碲镉汞线性雪崩器件(HgCdTe APD)的过剩噪声因子接近1,几乎无过剩噪声;相对于盖革模式的雪崩器件,没有死时间和后脉冲,不需要淬灭电路,具有超高动态范围,光谱响应范围宽且可调,探测效率和误计数率可独立优化,开辟了红外波段光子计数成像的新应用领域,在天文探测、激光雷达、自由空间通信等应用中具有重要价值。美国雷神(Raytheon)公司和DRS技术公司、法国CEA/LETI实验室和Lynred公司、英国Leonardo公司先后实现了碲镉汞线性雪崩探测器的单光子计数。文中总结了欧美国家在碲镉汞光子计数型线性雪崩探测器研究方面的技术路线和研究现状,分析了吸收倍增... 相似文献
11.
A few years ago, visible detection was demonstrated using advanced substrate thinning processes on flip-chip hybridized HgCdTe
focal-plane arrays, in both French and US laboratories. Constant quantum efficiency was demonstrated at LETI-Sofradir from
the short-wave infrared (IR) (2.5 μm cut-off) down to the visible range in 2006, validating complete CdZnTe substrate removal. This paper presents and discusses
HgCdTe photodiode spectral response characterization, focusing on the short-wavelength part of the spectrum. We confirm the
extended sensitivity of middle- and long-wave diodes: constant quantum efficiency has been observed from 10 μm down to 230 nm in the ultraviolet (UV). Such a unique property may be useful for very large-bandwidth spectrometers requiring
monolithic detectors. Avalanche gain of middle-wave avalanche photodiodes has also been investigated in both the visible and
the UV range. We demonstrate here that the avalanche gain remains constant while keeping a very low excess noise factor. This
result opens the way to low-flux applications in this wavelength range. 相似文献
12.
T. J. De Lyon G. L. Olson J. A. Roth J. E. Jensen A. T. Hunter M. D. Jack S. L. Bailey 《Journal of Electronic Materials》2002,31(7):688-693
The application of spectroscopic ellipsometry (SE) for real-time composition determination during molecular beam epitaxy (MBE)
growth of Hg1−xCdxTe alloys with x>0.5 is reported. Techniques previously developed for SE determination of composition in long-wavelength infrared
(LWIR) HgCdTe have been successfully extended to near-infrared HgCdTe avalanche photodiode (APD) device structures with x
values in the range of 0.6–0.8. Ellipsometric data collected over a spectral range of 1.7–5 eV were used to measure depth
profiles of HgCdTe alloy composition through the use of an optical model of the growth surface. The optical model used a dielectric-function
database collected through the growth of a set of HgCdTe calibration samples with x ranging from 0.6 to 0.8. The sensitivity
of this SE method of composition determination is estimated to be Δx ∼0.0002 at x=0.6, which is sufficiently low to sense
composition changes arising from flux variations of less than 0.1%. Errors in composition determination because of Hg-flux
variations appear to be inconsequential, while substrate-temperature fluctuations have been observed to alter the derived
composition at a rate of −0.0004/°C. By comparing the composition inferred from SE and postgrowth 300 K IR transmission measurements
on a set of APD device structures, the run-to-run precision of the Se-derived composition (at x=0.6) is estimated to be ±0.0012,
which is equivalent to the precision achieved with the same instrumentation during the growth of mid-wavelength infrared (MWIR)
HgCdTe alloys in the same MBE system. 相似文献
13.
M.B. Reine J.W. Marciniec K.K. Wong T. Parodos J.D. Mullarkey P.A. Lamarre S.P. Tobin K.A. Gustavsen G.M. Williams 《Journal of Electronic Materials》2007,36(8):1059-1067
This paper reports data for back-illuminated planar n-on-p HgCdTe electron-initiated avalanche photodiode (e-APD) 4 × 4 arrays with large unit cells (250 × 250 μm2). The arrays were fabricated from p-type HgCdTe films grown by liquid phase epitaxy (LPE) on CdZnTe substrates. The arrays were bump-mounted to fanout boards
and characterized in the back-illuminated mode. Gain increased exponentially with reverse bias voltage, and the gain versus
bias curves were quite uniform from element to element. The maximum gain measured was 648 at −11.7 V for a cutoff wavelength
of 4.06 μm at 160 K. For the same reverse-bias voltage, the gains measured at 160 K for elements with two different cutoff wavelengths
(3.54 μm and 4.06 μm at 160 K) show an exponential increase with increasing cutoff wavelength, in agreement with Beck’s empirical model for gain
versus voltage and cutoff wavelength in HgCdTe e-APDs. Spot scan data show that both the V = 0 response and the gain at V = −5.0 V
are spatially uniform over the large junction area. To the best of our knowledge, these are the first spot scan data for avalanche
gain ever reported for HgCdTe e-APDs. Capacitance versus voltage data are consistent with an ideal abrupt junction having
a donor concentration equal to the indium concentration in the LPE film.
U.S. Workshop on the Physics and Chemistry of II-VI Materials Newport Beach, California October 10–12, 2006. 相似文献
14.
D. Chandra H. F. Schaake F. Aqariden T. Teherani M. A. Kinch P. D. Dreiske D. F. Weirauch H. D. Shih 《Journal of Electronic Materials》2006,35(6):1470-1473
Exposure to specific damage introduced by either ion implantation or ion milling converts p-type short wavelength infrared
(SWIR) HgCdTe to n-type in a manner similar to the conversions in medium wavelength infrared (MWIR) or long wavelength infrared
(LWIR) mercury cadmium telluride. However, the depth of conversion for SWIR Hg1−xCdxTe, with x=0.48, is approximately 300% smaller when compared to the depth of conversion for MWIR HgCdTe for an identical degree
of ion milling. The depth of conversion, or the n/p junction depth, tracks linearly the extent of surface removals by ion
milling when the metal vacancy concentration is held invariant. These results can be correlated to the interaction between
metal vacancies and a product of the lattice damage process resulting from ion milling. The observation of a linear dependence
of this depth on the degree or time of ion milling rules out the existence of a diffusive barrier in the transfer of this
product for both MWIR and SWIR HgCdTe. 相似文献
15.
M.B. Reine J.W. Marciniec K.K. Wong T. Parodos J.D. Mullarkey P.A. Lamarre S.P. Tobin R.W. Minich K.A. Gustavsen M. Compton G.M. Williams 《Journal of Electronic Materials》2008,37(9):1376-1386
This article reports new characterization data for large-area (250 μm × 250 μm) back-illuminated planar n-on-p HgCdTe electron-initiated avalanche photodiodes (e-APDs). These e-APDs were fabricated in p-type HgCdTe films grown by liquid-phase epitaxy (LPE) on CdZnTe substrates. We previously reported that these arrays exhibit
gain that increases exponentially with reverse bias voltage, with gain-versus-bias curves that are quite uniform from element
to element, and with a maximum gain of 648 at −11.7 V at 160 K for a cutoff wavelength of 4.06 μm. Here we report new data on these planar e-APDs. Data from a third LPE film with a longer cutoff wavelength (4.29 μm at 160 K) supports the exponential dependence of gain on cutoff wavelength, for the same bias voltage, that we reported
for the first two films (with cutoffs of 3.54 μm and 4.06 μm at 160 K), in agreement with Beck’s empirical model for gain versus voltage and cutoff wavelength in HgCdTe e-APDs. Our
lowest gain-normalized current density at 80 K and zero field-of-view is 0.3 μA/cm2 at −10.0 V for a cutoff of 4.23 μm at 80 K. We report data for the temperature dependence of gain over 80 K to 200 K. We report, for the first time, the dependence
of measured gain on junction area for widely spaced circular diodes with radii of 20 μm to 175 μm. We interpret the variation of measured gain with junction area in terms of an edge-enhanced electric field, and fit the
data with a two-gain model having a lower interior gain and a higher edge gain. We report data for the excess noise factor
F(M) near unity for gains up to 150 at 196 K. We describe the abrupt breakdown phenomenon seen in most of our devices at high
reverse bias. 相似文献
16.
碲镉汞线性雪崩焦平面探测器具有高增益、高带宽及低过剩噪声等特点,在航空航天、天文观测、军事装备及地质勘探等领域展现了巨大的应用潜力。目前,国内已经开展了碲镉汞线性雪崩焦平面器件的研制工作,但缺乏评价其性能的方法及标准,同时对其的应用仍然处于探索阶段。首先分析了表征线性雪崩焦平面器件性能的关键参数,同时基于碲镉汞线性雪崩焦平面器件的特点,探讨了雪崩焦平面器件在主/被动红外成像、快速红外成像等领域的应用,最后对碲镉汞雪崩焦平面器件的未来发展进行了展望。 相似文献
17.
Status of the MBE technology at leti LIR for the manufacturing of HgCdTe focal plane arrays 总被引:2,自引:0,他引:2
P. Ferret J. P. Zanatta R. Hamelin S. Cremer A. Million M. Wolny G. Destefanis 《Journal of Electronic Materials》2000,29(6):641-647
This paper presents recent developments that have been made in Leti Infrared Laboratory in the field of molecular beam epitaxy
(MBE) growth and fabrication of medium wavelength and long wavelength infrared (MWIR and LWIR) HgCdTe devices. The techniques
that lead to growth temperature and flux control are presented. Run to run composition reproducibility is investigated on
runs of more than 15 consecutively grown layers. Etch pit density in the low 105 cm−2 and void density lower than 103 cm−2 are obtained routinely on CdZnTe substrates. The samples exhibit low n-type carrier concentration in the 1014 to 1015 cm−3 range and mobility in excess of 105 cm2/Vs at 77 K for epilayers with 9.5 μm cut-off wavelength. LWIR diodes, fabricated with an-on-p homojunction process present
dynamic resistance area products which reach values of 8 103 Ωcm2 for a biased voltage of −50 mV and a cutoff wavelength of 9.5 μm at 77 K. A 320 × 240 plane array with a 30 μm pitch operating
at 77 K in the MWIR range has been developed using HgCdTe and CdTe layers MBE grown on a Germanium substrate. Mean NEDT value
of 8.8 mK together with an operability of 99.94% is obtained. We fabricated MWIR two-color detectors by the superposition
of layers of HgCdTe with different compositions and a mixed MESA and planar technology. These detectors are spatially coherent
and can be independently addressed. Current voltage curves of 60 × 60 μm2 photodiodes have breakdown voltage exceeding 800 mV for each diode. The cutoff wavelength at 77 K is 3.1 μm for the MWIR-1
and 5 μm for the MWIR-2. 相似文献
18.
Majid Zandian D. Scott J. Garnett D. D. Edwall J. Pasko M. Farris M. Daraselia J. M. Arias J. Bajaj D. N. B. Hall S. Jacobson G. Luppino S. Parker 《Journal of Electronic Materials》2005,34(6):891-897
Growth of Hg1−xCdxTe by molecular beam epitaxy (MBE) has been under development since the early 1980s at Rockwell Scientific Company (RSC),
formerly the Rockwell Science Center; and we have shown that high-performance and highly reproducible MBE HgCdTe double heterostructure
planar p-on-n devices can be produced with high throughput for various single- and multiplecolor infrared applications. In
this paper, we present data on Hg1−xCdxTe epitaxial layers grown in a ten-inch production MBE system. For growth of HgCdTe, standard effusion cells containing CdTe
and Te were used, in addition to a Hg source. The system is equipped with reflection high energy electron diffraction (RHEED)
and spectral ellipsometry in addition to other fully automated electrical and optical monitoring systems. The HgCdTe heterostructures
grown in our large ten-inch Riber 49 MBE system have outstanding structural characteristics with etch-pit densities (EPDs)
in the low 104 cm−2 range, Hall carrier concentration in low 1014 cm−3, and void density <1000 cm2. The epilayers were grown on near lattice-matched (211)B Cd0.96Zn0.04Te substrates. High-performance mid wavelength infrared (MWIR) devices were fabricated with R0A values of 7.2×106 Ω-cm2 at 110 K, and the quantum efficiency without an antireflection coating was 71.5% for cutoff wavelength of 5.21 μm at 37 K.
For short wavelength infrared (SWIR) devices, an R0A value of 9.4×105 Ω-cm2 at 200 K was obtained and quantum efficiency without an antireflection coating was 64% for cutoff wavelength of 2.61 μm at
37 K. These R0A values are comparable to our trend line values in this temperature range. 相似文献
19.
Jeff Beck Terry Welch Pradip Mitra Kirk Reiff Xiaoli Sun James Abshire 《Journal of Electronic Materials》2014,43(8):2970-2977
An HgCdTe electron avalanche photodiode (e-APD) detector has been developed for lidar receivers, one application of which is integrated path differential absorption lidar measurements of such atmospheric trace gases as CO2 and CH4. The HgCdTe APD has a wide, visible to mid-wave-infrared, spectral response, high dynamic range, substantially improved sensitivity, and an expected improvement in operational lifetime. A demonstration sensor-chip assembly consisting of a 4.3 μm cutoff HgCdTe 4 × 4 APD detector array with 80 μm pitch pixels and a custom complementary metal–oxide–semiconductor readout integrated circuit was developed. For one typical array the APD gain was 654 at 12 V with corresponding gain normalized dark currents ranging from 1.2 fA to 3.2 fA. The 4 × 4 detector system was characterized at 77 K with a 1.55 μm wavelength, 1 μs wide, laser pulse. The measured unit gain detector photon conversion efficiency was 91.1%. At 11 V bias the mean measured APD gain at 77 K was 307.8 with σ/mean uniformity of 1.23%. The average, noise-bandwidth normalized, system noise-equivalent power (NEP) was 1.04 fW/Hz1/2 with a σ/mean of 3.8%. The measured, electronics-limited, bandwidth of 6.8 MHz was more than adequate for 1 μs pulse detection. The system had an NEP (3 MHz) of 0.4 fW/Hz1/2 at 12 V APD bias and a linear dynamic range close to 1000. A gain-independent quantum-limited SNR of 80% of full theoretical was indicative of a gain-independent excess noise factor very close to 1.0 and the expected APD mode quantum efficiency. 相似文献
20.
J. B. Varesi R. E. Bornfreund A. C. Childs W. A. Radford K. D. Maranowski J. M. Peterson S. M. Johnson L. M. Giegerich T. J. de Lyon J. E. Jensen 《Journal of Electronic Materials》2001,30(6):566-573
We have developed the capability to grow HgCdTe mid-wave infrared radiation double-layer heterojunctions (MWIR DLHJs) on 4″
Si wafers by molecular beam epitaxy (MBE), and fabricate devices from these wafers that are comparable to those produced by
mature technologies. Test data show that the detectors, which range in cutoff wavelength over 4–7 μm, are comparable to the
trendline performance of liquid phase epitaxy (LPE)-grown material. The spectral characteristics are similar, with a slight
decrease in quantum efficiency attributable to the Si substrate. With respect to R0A, the HgCdTe/Si devices are closer to the theoretical radiative-limit than LPE-grown detectors. Known defect densities in
the material have been correlated to device performance through a simple model. Slight 1/f noise increases were measured in
comparison to the LPE material, but the observed levels are not sufficient to significantly degrade focal plane array (FPA)
performance. In addition to discrete detectors, two FPA formats were fabricated. 128×128 FPAs show MWIR sensitivity comparable
to mature InSb technology, with pixel operability values in excess of 99%. A 640×480 FPA further demonstrates the high-sensitivity
and high-operability capabilities of this material. 相似文献