共查询到20条相似文献,搜索用时 31 毫秒
1.
C. A. Musca J. Antoszewski J. M. Dell L. Faraone S. Terterian 《Journal of Electronic Materials》2003,32(7):622-626
Planar p-on-n HgCdTe heterojunction photodiodes have been fabricated using a plasma-induced type conversion process for device
junction isolation. The technique is presented as a fully planar alternative technology to the commonly used mesa isolation
structure. The starting material consisted of an indium-doped n-type mid-wavelength infrared (MWIR) HgCdTe absorbing layer
that was capped by a 1-μm-thick wider bandgap arsenic-doped p-type layer. Junction-isolated p-on-n diodes were formed by selectively
p-to-n type converting the p-type cap layer using a plasma process. Photodiode dark current-voltage measurements were performed
as a function of temperature, along with noise and responsivity. The devices have cut-off wavelengths between 4.8 μm and 5.0
μm, exhibit diffusion-limited dark currents down to 145 K, give R0A values greater than 1 × 107Ω·cm2 at 80 K and greater than 1 × 105Ω·cm2 at 120 K, and have negligible 1/f noise current at zero applied bias. 相似文献
2.
Molecular-beam epitaxial growth of HgCdTe infrared focal-plane arrays on silicon substrates for midwave infrared applications 总被引:1,自引:0,他引:1
T. J. de Lyon R. D. Rajavel J. A. Vigil J. E. Jensen O. K. Wu C. A. Cockrum S. M. Johnson G. M. Venzor S. L. Bailey I. Kasai W. L. Ahlgren M. S. Smith 《Journal of Electronic Materials》1998,27(6):550-555
Molecular beam epitaxy has been employed to deposit HgCdTe infrared detector structures on Si(112) substrates with performance
at 125K that is equivalent to detectors grown on conventional CdZnTe substrates. The detector structures are grown on Si via
CdTe(112)B buffer layers, whose structural properties include x-ray rocking curve full width at half maximum of 63 arc-sec
and near-surface etch pit density of 3–5 × 105 cm−2 for 9 μm thick CdTe films. HgCdTe p+-on-n device structures were grown by molecular beam epitaxy (MBE) on both bulk CdZnTe and Si with 125K cutoff wavelengths
ranging from 3.5 to 5 μm. External quantum efficiencies of 70%, limited only by reflection loss at the uncoated Si-vacuum
interface, were achieved for detectors on Si. The current-voltage (I-V) characteristics of MBE-grown detectors on CdZnTe and
Si were found to be equivalent, with reverse breakdown voltages well in excess of 700 mV. The temperature dependences of the
I-V characteristics of MBE-grown diodes on CdZnTe and Si were found to be essentially identical and in agreement with a diffusion-limited
current model for temperatures down to 110K. The performance of MBE-grown diodes on Si is also equivalent to that of typical
liquid phase epitaxy-grown devices on CdZnTe with R0A products in the 106–107 Θ-cm2 range for 3.6 μm cutoff at 125K and R0A products in the 104–105 Θ-cm2 range for 4.7 μm cutoff at 125K. 相似文献
3.
W. W. Bewley J. R. Lindle I. Vurgaftman J. R. Meyer J. B. Varesi S. M. Johnson 《Journal of Electronic Materials》2003,32(7):651-655
We have investigated the negative luminescence properties of a midwave-infrared (MWIR) HgCdTe photodiode (λco = 5.3 μm at 295 K) grown on a silicon substrate. The internal negative luminescence efficiencies measured using a self-referencing
optical technique were 88% throughout the 3–5 μm spectral region and nearly independent of temperature in the 240–300 K range.
This corresponds to an apparent temperature reduction of 53 K at room temperature and 35 K at 240 K. Efficiencies measured
by an electrical modulation technique were consistent with the measured internal efficiencies and the measured reflectivity
of the device. This is the highest efficiency and largest apparent reduction in temperature reported to date, and slightly
higher than that measured earlier for photodiodes grown on CdZnTe despite a longer cut-off wavelength. These results provide
further indication that the HgCdTe/Si photovoltaic device technology is capable of combining high quality with high yield. 相似文献
4.
P. S. Wijewarnasuriya M. Zandian J. Phillips D. Edwall R. E. Dewames G. Hildebrandt J. Bajaj J. M. Arias A. I. D’Souza F. Moore 《Journal of Electronic Materials》2002,31(7):726-731
State-of-the-art large-area photovoltaic (PV) detectors fabricated in HgCdTe grown by molecular beam epitaxy (MBE) have been
demonstrated for the Crosstrack Infrared Sounder (CrIS) instrument. Large-area devices (1 mm in diameter) yielded excellent
electrical and optical performance operating at 81 K for λc ∼ 15 μm, at 98 K for λc ∼ 9 μm, and λc ∼ 5-μm spectral cutoffs. Fabricated detectors have near-theoretical electrical performance, and Anti Reflection coated quantum
efficiency (QE) is greater than 0.70. Measured average R0A at 98 K is 2.0E7 Ωcm2, and near-theoretical QEs greater than 0.90 were obtained on detectors with λc ∼ 5-μm spectral cutoffs. These state-of-the-art large-area PV detector results reflect high-quality HgCdTe grown by MBE on
CdZnTe substrates in all three spectral bands of interest. 相似文献
5.
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
6.
Molecular beam epitaxial HgCdTe material characteristics and device performance: Reproducibility status 总被引:1,自引:0,他引:1
J. Bajaj J. M. Arias M. Zandian J. G. Pasko L. J. Kozlowski R. E. De Wames W. E. Tennant 《Journal of Electronic Materials》1995,24(9):1067-1076
Extensive material, device, and focal plane array (FPA) reproducibility data are presented to demonstrate significant advances
made in the molecular beam epitaxial (MBE) HgCdTe technology. Excellent control of the composition, growth rate, layer thickness,
doping concentration, dislocation density, and transport characteristics has been demonstrated. A change in the bandgap is
readily achieved by adjusting the beam fluxes, demonstrating the flexibility of MBE in responding to the needs of infrared
detection applications in various spectral bands. High performance of photodiodes fabricated on MBE HgCdTe layers reflects
on the overall quality of the grown material. The photodiodes were planar p-on-n junctions fabricated by As ion-implantation
into indium doped, n-type, in situ grown double layer heterostructures. At 77K, diodes fabricated on MBE Hg1−xCdxTe with x ≈ 0.30 (λco
≈ 5.6 μm), x ≈ 0.26 (λco
≈ 7 μm), x ≈ 0.23 (λco ≈ 10 μm) show R0A products in excess of 1 x 106 ohm-cm2, 7 x 105 ohm-cm2, and 3 x 102 ohm-cm2, respectively. These devices also show high quantum efficiency. As a means to assess the uniformity of the MBE HgCdTe material,
two-dimensional 64 x 64 and 128 x 128 mosaic detector arrays were hybridized to Si multiplexers. These focal plane arrays
show an operability as high as 97% at 77K for the x ≈ 0.23 spectral band and 93% at 77K for the x ≈ 0.26 spectral band. The
operability is limited partly by the density of void-type defects that are present in the MBE grown layers and are easily
identified under an optical microscope. 相似文献
7.
P. Mitra F. C. Case M. B. Reine T. Parodos S. P. Tobin P. W. Norton 《Journal of Electronic Materials》1999,28(6):589-595
New results are reported on the growth of high performance medium wavelength infrared (3–5 μm) (MWIR) HgCdTe photodiodes in
the three-layer P-n-N configuration. The detector structures were grown in situ by metalorganic vapor phase epitaxy (MOVPE) on (211)B oriented CdZnTe substrates. The mobilities of the single n-type layers
with x-values of ∼0.30 are in the range of (3–4.5)×104 cm2/V-s at 80K. The lifetimes on unpassivated films range from 1–5 and 4–10 μs at 80 and 180K, respectively, which are within
a factor of two or less of the lifetimes calculated for Auger-1 and radiative recombination. The P-n-N films were processed
into variable-area backside-illuminated diagnostic arrays and tested for quantum efficiency, spectral response, RDA, I–V curves and 1/f noise in the 120–180K range. The internal one-dimensional quantum efficiencies are in the range of 85–100%.
The optical collection lengths are typically ∼25 μm. I–V curves showed that diffusion current is the dominant junction current
mechanism for temperatures ≥100K. R0A values are at the one-dimensional limit for n-side diffusion currents over the 100–180K range. 1/f noise was measured to
be very low at 120K and is the same as that measured in similarly processed arrays from recent LPE grown P-on-N heterojunctions.
The results demonstrate that MOVPE growth can be used for large area, high performance MWIR HgCdTe detector arrays operating
in the 120–180K temperature range. 相似文献
8.
A. I. D’Souza J. Bajaj R. E. De Wames D. D. Edwall P. S. Wijewarnasuriya N. Nayar 《Journal of Electronic Materials》1998,27(6):727-732
Mid wavelength infrared p-on-n double layer planar heterostructure (DLPH) photodiodes have been fabricated in HgCdTe double
layers grown in situ by liquid phase epitaxy (LPE), on CdZnTe and for the first time on CdTe/sapphire (PACE-1). Characterization of these devices
shed light on the nature of the material limits on device performance for devices performing near theoretical limits. LPE
double layers on CdZnTe and on PACE-1 substrates were grown in a horizontal slider furnace. All the photodiodes are p-on-n
heterostructures with indium as the n-type dopant and arsenic the p-type dopant. Incorporation of arsenic is via implantation
followed by an annealing step that was the same for all the devices fabricated. The devices are passivated with MBE CdTe.
Photodiodes have been characterized as a function of temperature. R0Aimp values obtained between 300 and 78K are comparable for the two substrates and are approximately a factor of five below theoretical
values calculated from measured material parameters. The data, for the PACE-1 substrate, indicates diffusion limited performance
down to 110K. Area dependence gives further indications as to the origin of diffusion currents. Comparable R0Aimp for various diode sizes indicates a p-side origin. R0A and optical characteristics for the photodiodes grown on lattice-matched CdZnTe substrates and lattice mismatched PACE-1
are comparable. Howover, differences were observed in the noise characteristics of the photodiodes. Noise was measured on
50 × 50 μm devices held under a 100 mV reverse bias. At 110K, noise spectrum for devices from the two substrates is in the
low 10−15 A/Hz1/2 range. This value reflects the Johnson noise of the room temperature 1010 Ω feedback resistor in the current amplifier that limits the minimum measurable noise. Noise at 1 Hz, −100 mV and 120K for
the 4.95 μm PACE-1 devices is in the 1–2 × 10−14 A/Hz1/2, a factor of 5–10 lower than previously grown typical PACE-1 n+-on-p layers. Noise at 120K for the 4.60 μm PACE-1 and LPE on CdZnTe was again below the measurement technique limit. Greatest
distinction in the noise characteristics for the different substrates was observed at 163K. No excess low frequency noise
was observed for devices fabricated on layers grown by LPE on lattice-matched CdZnTe substrates. Photodiode noise measured
at 1Hz, −100 mV and 163K in the 4.60 μm PACE-1 layer is in the 1–2×10−13 A/Hz1/2, again a factor of 5–10 lower than previously grown PACE-1 n+-on-p layers. More variation in noise (4×10−13−2×10−12 A/Hz1/2) was observed for devices in the 4.95 μm PACE-1 layer. DLPH devices fabricated in HgCdTe layers grown by LPE on lattice-matched
CdZnTe and on lattice-mismatched PACE-1 have comparable R0A and quantum efficiency values. The distinguishing feature is that the noise is greater for devices fabricated in the layer
grown on lattice mismatched substrates, suggesting dislocations inherent in lattice mismatched material affects excess low
frequency noise but not zero bias impedance. 相似文献
9.
P. Mitra T. R. Schimert F. C. Case S. L. Barnes M. B. Reine R. Starr M. H. Weiler M. Kestigian 《Journal of Electronic Materials》1995,24(9):1077-1085
We report new results on metalorganic chemical vapor deposition (MOCVD)in situ growth of long wavelength infrared (LWIR) P-on-n and medium wavelength infrared (MWIR) n-on-P HgCdTe heterojunction photodiodes using the interdiffused multilayer process (IMP). The n-type regions are doped with iodine using the precursor ethyl iodide (El). I-doped HgCdTe using El has mobilities higher than that obtained on undoped background annealed films and are comparable to LPE grown In-doped HgCdTe. The p-type layers are doped with arsenic from either tertiarybutylarsine (TBAs) or a new precursor,tris-dimethylaminoarsenic (DMAAs). The substrates used in this work are lattice matched CdZnTe oriented (211)B or (100)4°→«110». Junction quality was assessed by fabricating and characterizing backside-illuminated arrays of variable-area circular mesa photodiodes. This paper presents four new results. First, carrier lifetimes measured at 80K on arsenic doped single HgCdTe layers are generally longer for films doped from the new precursor DMAAs than from TBAs. Second, we present data on the first P-on-n HgCdTe photodiodes grownin situ with DMAAs which have R0A products limited by g-r current at 80K for λco = 7–12 μm, comparable to the best R0A products we have achieved with TBAs. Third, we report the first experimental data on a new HgCdTe device architecture, the n-on-P heterojunction, with a wide gap p-type layer which allows radiation incident through the substrate to be absorbed in a narrower gap n-type layer, thereby eliminating interface recombination effects. With the n-on-P architecture, MWIR photodiodes were obtained reproducibly with classical spectral response shapes, high quantum efficiencies (70-75%) and R0A products above 2 x 105 ohm-cm2 for λco = 5.0 μm at 80K. Fourth, we report 40K data for LWIR P-on-n HgCdTe heterojunction photodiodes (using TBAs), with R0A values of 2 x 104 ohm-cm2 for λco = 11.7 μm and 5 x 105 ohm-cm2 for λco - 9.4 μm. These are the highest R0A values reported to date for LWIR P-on-n heterojunctions grownin situ by MOCVD. 相似文献
10.
P. S. Wijewarnasuriya M. Zandian D. B. Young J. Waldrop D. D. Edwall W. V. Mclevige D. Lee J. Arias A. I. D’Souza 《Journal of Electronic Materials》1999,28(6):649-653
Long wavelength infrared molecular beam epitaxy (MBE) grown p-on-n Hg1−xCdxTe double layer planar heterostructure (DLPH) detectors have been characterized to determine the dominant mechanisms limiting
their performance. Material defects have been identified as critical factors that limit 40K performance operability. This
effort has concentrated on identifying microscopic defects, etch pit density (EPD) and relating these defects to the device
performance. Visual inspection indicates defect densities as high as 105 per cm2 with a spatial extent as observed by atomic force microscope in the range of micrometers extending several micrometers beneath
the surface. At high EPD values (greater than low 106 cm−2) zero bias resistance (R0) at 40K decreases as roughly as the square of the EPD. At 78K, however, measured R0 is not affected by the EPD up to densities as high as mid-106 cm−2. Visual defects greater than 2–3 μm than ∼2 μm in size (micro-void defects) result in either a single etch pit or a cluster
of etch pits. Large variations in a cross-wafer etch pit distribution are most likely a major contributor to the observed
large spreads in 40K R0. This study gives some insight to the present limitation to achieve higher performance and high operability for low temperature
infrared applications on MBE grown HgCdTe material. 相似文献
11.
J. K. Markunas L. A. Almeida R. N. Jacobs J. Pellegrino S. B. Qadri N. Mahadik J. Sanghera 《Journal of Electronic Materials》2010,39(6):738-742
Large-area high-quality Hg1–x
Cd
x
Te sensing layers for infrared imaging in the 8 μm to 12 μm spectral region are typically grown on bulk Cd1–x
Zn
x
Te substrates. Alternatively, epitaxial CdTe grown on Si or Ge has been used as a buffer layer for high-quality epitaxial
HgCdTe growth. In this paper, x-ray topographs and rocking-curve full-width at half-maximum (FWHM) data will be presented
for recent high-quality bulk CdZnTe grown by the vertical gradient freeze (VGF) method, previous bulk CdZnTe grown by the
vertical Bridgman technique, epitaxial CdTe buffer layers on Si and Ge, and a HgCdTe layer epitaxially grown on bulk VGF CdZnTe. 相似文献
12.
R. D. Rajavel D. M. Jamba J. E. Jensen O. K. Wu C. Le Beau J. A. Wilson E. Patten K. Kosai J. Johnson J. Rosbeck P. Goetz S. M. Johnson 《Journal of Electronic Materials》1997,26(6):476-481
The first report of molecular beam epitaxial growth and performance of HgCdTe two-color detectors for the simultaneous detection
of radiation at 4.1 and 4.5 μm is presented. In-situ doped devices with the n-p-n architecture were grown by molecular beam
epitaxy on (211)B CdZnTe substrates. Representative structures exhibited x-ray rocking curves with full width at half-maxima
of 40–60 arcs. The typical near surface etch pit density in these structures were 4−7 × 106 cm−2. The devices were processed as mesa diodes and electrical contacts were made to the two n-type layers and the p-type layer
to facilitate simultaneous operation of the two p-n junctions. The spectral response characteristics of the devices were characterized
by sharp turn-on and turn-off for both bands, with R0A values >5 × 105 ωcm2 at 77K. The detectors exhibited quantum efficiencies >70% in both bands. 相似文献
13.
Spectral crosstalk by radiative recombination in sequential-mode, dual mid-wavelength infrared band HgCdTe detectors 总被引:1,自引:0,他引:1
R. A. Coussa A. M. Gallagher K. Kosai L. T. Pham G. K. Pierce E. P. Smith G. M. Venzor T. J. De Lyon J. E. Jensen B. Z. Nosho J. A. Roth J. R. Waterman 《Journal of Electronic Materials》2004,33(6):517-525
For small pixel, infrared (IR) focal plane arrays (FPAs), Raytheon Vision Systems’ architecture for integrated, dual-band
detectors uses the sequential mode of the n-p+-n configuration. There is a single indium bump per pixel, leaving the p+ layer floating, and the operating polarity of the bias selects the spectral sensitivity by reverse-biasing the active p-n
junction. Photogenerated minority carriers in the absorber layer of the forward-biased inactive photodiode are lost through
recombination. This paper is the first report of a new optical crosstalk mechanism that occurs in sequential-mode, dual-band
detectors. In the long-wavelength mode under out-of-band, short-wavelength illumination, radiative recombination yields emission
near the bandgap energy of the short-wavelength absorber layer, resulting in a spurious short-wavelength response that appears
as spectral crosstalk. We present experimental and device modeling results on the spectral crosstalk in molecular-beam-epitaxy-grown
HgCdTe arrays with the cutoff wavelength of both bands in the 4–5-μm range. 相似文献
14.
V. Natarajan N. R. Taskar I. B. Bhat S. K. Ghandhi 《Journal of Electronic Materials》1988,17(6):479-483
The organometallic vapor phase epitaxy of HgCdTe onto (100)2°-(110) GaAs substrates is described in this paper. A buffer layer
of CdTe has been grown prior to the growth of HgCdTe, to take up the large lattice mismatch with the GaAs. Considerations
for the thickness of this buffer layer are outlined, and it is shown by quantitative Secondary Ion Mass Spectroscopy that
there is negligible diffusion of gallium from the GaAs substrate for the growth conditions described. Hall effect measurements
give mobilities comparable to those reported for bulk grown crystals. An extrinsicn-type carrier concentration of 2 × 1016/cm3 is obtained, and is mainly due to residual impurities in the starting chemicals. The alloy composition has been determined
at 298 K by Fourier transform infrared transmission (FTIR) spectrometry; this is found to be extremely uniform over a 15 ×
7 mm area, as evidenced by an overlapping of FTIR plots taken over this area. HgCdTe layers have been grown on buffer layers
varying in thickness from 0.1 to 1.9μm. It is found that a buffer thickness of about 1.9μm or larger is required to obtain high quality HgCdTe, both in terms of the electrical characteristics (mobility and carrier
concentration) and the infrared transmission curves (peak transmission). 相似文献
15.
High-Performance LWIR MBE-Grown HgCdTe/Si Focal Plane Arrays 总被引:1,自引:0,他引:1
Richard Bornfreund Joe P. Rosbeck Yen N. Thai Edward P. Smith Daniel D. Lofgreen Mauro F. Vilela Aimee A. Buell Michael D. Newton Kenneth Kosai Scott M. Johnson Terry J. de Lyon John E. Jensen Meimei Z. Tidrow 《Journal of Electronic Materials》2007,36(8):1085-1091
We have been actively pursuing the development of long-wavelength infrared (LWIR) HgCdTe grown by molecular beam epitaxy (MBE)
on large-area silicon substrates. The current effort is focused on extending HgCdTe/Si technology to longer wavelengths and
lower temperatures. The use of Si versus bulk CdZnTe substrates is being pursued due to the inherent advantages of Si, which
include available wafer sizes (as large as 300 mm), lower cost (both for the substrates and number of die per wafer), compatibility
with semiconductor processing equipment, and the match of the coefficient of thermal expansion with silicon read-out integrated
circuit (ROIC). Raytheon has already demonstrated low-defect, high-quality MBE-grown HgCdTe/Si as large as 150 mm in diameter.
The focal plane arrays (FPAs) presented in this paper were grown on 100 mm diameter (211)Si substrates in a Riber Epineat
system. The basic device structure is an MBE-grown p-on-n heterojunction device. Growth begins with a CdTe/ZnTe buffer layer followed by the HgCdTe active device layers; the entire
growth process is performed in␣situ to maintain clean interfaces between the various layers. In this experiment the cutoff wavelengths were varied from 10.0 μm to 10.7 μm at 78 K. Detectors with >50% quantum efficiency and R
0
A ∼1000 Ohms cm2 were obtained, with 256 × 256, 30 μm focal plane arrays from these detectors demonstrating response operabilities >99%.
Work supported by the Missile Defense Agency (MDA) through CACI Technologies, Inc. subcontract no. 601-05-0088, NVESD technical
task order no. TTO-01, prime contract no. DAAB07-03-D-C214, (delivery order no. 0016) 相似文献
16.
J. Baylet O. Gravrand E. Laffosse C. Vergnaud S. Ballerand B. Aventurier J. C. Deplanche P. Ballet P. Castelein J. P. Chamonal A. Million G. Destefanis 《Journal of Electronic Materials》2004,33(6):690-700
The third generation of HgCdTe infrared-detector focal-plane arrays (FPAs) should be able to detect simultaneously in two
spectral bands. The feasibility of this type of dual-band detectors has already been shown in our laboratory with a pixel
size of 50 μm in the 3–5-μm wavelength range. To improve the detector resolution, it is necessary to decrease the pixel pitch.
Dry etching is a key process technology to fulfill this goal because of the high aspect-ratio structures needed (typically
10–15-μm deep and 2–5-μm wide trenches). In this paper, we present results of a parametric study on HgCdTe dry etching, as
well as results obtained on detector arrays made with the dry-etching technique. The etching study has been done in a microwave
plasma reactor with the aim of controlling the surface roughness, the etch rate, and the slope of the trench side. We show
how these parameters are influenced by the reactive gas-mixture composition (based on CH4, H2, and Ar) and the substrate self-bias. We show how polymer film deposition can prevent etching from occurring but can improve
anisotropy. We show some examples of results obtained when manufacturing the trenches that separate the pixels, keeping a
high fill factor, and anisotropic etching. We also show results of the material surface characterizations done with scanning
electron microscopy (SEM) and Hall effect measurements. These studies allow us to evaluate and compare the damages done to
the HgCdTe surface with different etching conditions. Our best process allows us to make a light electrical damage, confined
to less than a micron deep in the material. Using the dry-etching process, we have developed detector arrays fabricated with
a pixel pitch as low as 30 μm. We finally present the results of the first electrical characterizations made on these arrays,
showing promising results for the development of high-resolution dual-band detectors. 相似文献
17.
J. R. Lindle W. W. Bewley I. Vurgaftman J. R. Meyer J. L. Johnson M. L. Thomas E. C. Piquette W. E. Tennant 《Journal of Electronic Materials》2004,33(6):600-603
The negative luminescence (NL) efficiency of a 5 mm×5 mm array (100% effective fill factor) of HgCdTe photodiodes (λco=4.8 μm at 295 K) has been measured as a function of temperature. The internal NL efficiency of ≈95% at λ=4 μm is nearly independent
of temperature in the 240–300 K range and, at 300 K, corresponds to an apparent temperature reduction of 60 K. This performance
is obtained at a reverse-bias saturation-current density of only 0.11 A/cm2 at 296 K. With large area, high efficiency, and low saturation-current density, our results demonstrate a level of NL device
performance at which such applications as cold shields for large-format focal plane arrays (FPAs) and multipoint nonuniformity
correctors appear practical. 相似文献
18.
Progress in MOVPE of HgCdTe for advanced infrared detectors 总被引:1,自引:0,他引:1
This paper reviews the significant progress made over the past five years in the development of metalorganic vapor phase epitaxy
(MOVPE) for the in situ growth of HgCdTe p-n junction devices for infrared detector arrays. The two basic approaches for MOVPE growth of HgCdTe,
the interdiffused multilayer process (IMP), and direct alloy growth (DAG) are compared. The paper then focuses on the progress
achieved with the IMP approach on lattice-matched CdZnTe substrates. The benefits of the precursors ethyl iodide (EI) and
tris-dimethylaminoarsenic (DMAAs) for controlled iodine donor doping and arsenic acceptor doping at dopant concentrations relevant
for HgCdTe junction devices are summarized along with the electrical and lifetime properties of n-type and p-type HgCdTe films
grown with these precursors. The relative merits of the two CdZnTe substrate orientations we have used, the (211)B and the
(100) with 4°–8° misorientation are compared, and the reasons why the (211)B is preferred are discussed. The growth and repeatability
results, based on secondary ion mass spectrometry analysis, are reported for a series of double-heterojunction p-n-N-P dual-band
HgCdTe films for simultaneous detection in the 3–5 μm and 8–10 μm wavelength bands. Finally, the device characteristics of
MOVPE-IMP in situ grown p-on-n heterojunction detectors operating in the 8–12 μm band are reviewed and compared with state-of-the-art liquid
phase epitaxial grown devices. 相似文献
19.
P.Y. Emelie S. Velicu C.H. Grein J.D. Phillips P.S. Wijewarnasuriya N.K. Dhar 《Journal of Electronic Materials》2008,37(9):1362-1368
The general approach and effects of nonequilibrium operation of Auger-suppressed HgCdTe infrared photodiodes are well understood.
However, the complex relationships of carrier generation and dependencies on nonuniform carrier profiles in the device prevent
the development of simplistic analytical device models with acceptable accuracy. In this work, finite element methods are
used to obtain self-consistent steady-state solutions of Poisson’s equation and the carrier continuity equations. Experimental
current–voltage characteristics between 120 K and 300 K of HgCdTe Auger-suppressed photodiodes with cutoff wavelength of λ
c = 10 μm at 120 K are fitted using our numerical model. Based on this fitting, we study the lifetime in the absorber region, extract
the current mechanisms limiting the dark current in these photodiodes, and discuss design and fabrication considerations in
order to optimize future HgCdTe Auger-suppressed photodiodes. 相似文献
20.
Heteroepitaxy of HgCdTe (211)B on Ge substrates by molecular beam epitaxy for infrared detectors 总被引:3,自引:0,他引:3
J. P. Zanatta P. Ferret G. Theret A. Million M. Wolny J. P. Chamonal G. Destefanis 《Journal of Electronic Materials》1998,27(6):542-545
Epitaxial growth of (211)B CdTe/HgCdTe has been achieved on two inch germanium (Ge) by molecular beam epitaxy (MBE). Germanium
was chosen as an alternative substrate to circumvent the weaknesses of CdZnTe wafers. The ease of surface preparation makes
Ge an attractive candidate among many other alternative substrates. Best MBE CdTe growth results were obtained on (211) Ge
surfaces which were exposed to arsenic and zinc fluxes prior to the MBE growth. This surface preparation enabled CdTe growth
with B-face crystallographic polarity necessary for the HgCdTe growth. This process was reproducible, and produced a smooth
and mirror-like surface morphology. The best value of the {422} x-ray double diffraction full width at half maximum measured
from the HgCdTe layer was 68 arc-s. We present the 486 point maps of FWHM statistical values obtained from CdTe/Ge and HgCdTe/CdTe/Ge.
High resolution microscopy electron transmission and secondary ion mass spectroscopy characterization results are also presented
in this paper. High-performance middle wavelength infrared HgCdTe 32-element photodiode linear arrays, using the standard
LETI/LIR planar n-on-p ion implanted technology, were fabricated on CdTe/Ge substrates. At 78K, photodiodes exhibited very
high R0A figure of merit higher than 106 Ωcm−2 for a cutoff wavelength of 4.8 μm. Excess low frequency noise was not observed below 150K. 相似文献