共查询到20条相似文献,搜索用时 78 毫秒
1.
Charles Musca Jaroslaw Antoszewski John Dell Lorenzo Faraone Józef Piotrowski Zenon Nowak 《Journal of Electronic Materials》1998,27(6):740-746
This paper describes a new multi-heterojunction n
+pp photovoltaic infrared photodetector. The device has been developed specifically for operation at temperatures of 200–300K
in the long wavelength (8–14 μm) range of the infrared spectrum. The new structure solves the perennial problems of poor quantum
efficiency and low dynamic resistance found in conventional long wavelength infrared photovoltaic detectors when operated
near room temperature. Computer simulations show that devices with properly optimized multiple heterojunctions are capable
of achieving the performance limits imposed by the statistical nature of thermal generation-recombination processes. In order
to demonstrate the technology, multiple heterojunction devices have been fabricated on epilayers grown by isothermal vapor
phase epitaxy of HgCdTe and in situ As p-type doping. The detector structures were formed using a combination of conventional dry etching, angled ion milling,
and angled thermal evaporation for contact metal deposition. These multi-junction n
+pp HgCdTe heterostructure devices exhibit performances which make them useful for many applications. D* of optically immersed
multiple heterostructure photovoltaic detectors exceeding 108cmHz1/2/W were measured at λ=10.6 μm and T=300K. 相似文献
2.
S. Velicu C.H. Grein P.Y. Emelie A. Itsuno J.D. Philips P. Wijewarnasuriya 《Journal of Electronic Materials》2010,39(7):873-881
In this work, we analyze Auger suppression in HgCdTe alloy-based device structures and determine the operation temperature
improvements expected when Auger suppression occurs. We identified critical material (absorber dopant concentration and minority-carrier
lifetime) requirements that must be satisfied for optimal performance characteristics. Calculated detectivity values of Auger-suppressed
and standard double-layer planar heterostructure (DLPH) devices demonstrate consistently higher maximum background-limited
temperatures over a range of cutoff wavelengths and generally higher detectivity values achieved by Auger-suppressed detectors.
Furthermore, these devices can operate with comparable performance at up to 100 K higher than DLPH detectors operating at
reference temperatures above 100 K. Results of these simulations demonstrate that Auger-suppressed detectors provide a significant
advantage over DLPH devices for high-temperature operation and are a viable candidate for thermoelectrically cooled detectors.
Experimental dark current–voltage (I–V) characteristics between 120 K and 300 K were fitted using numerical simulations. By fitting the temperature-dependent I–V experimental data, we determined that the observed negative differential resistance (NDR) is due to Auger suppression. More
specifically, NDR is attributed to full suppression of Auger-1 processes and partial (~70%) suppression of Auger-7 processes.
After Auger suppression, the remaining leakage current is principally limited by the Shockley–Read–Hall recombination component.
Part of the leakage current is also due to a residual Auger-7 current in the absorber due to the extrinsic p-type doping level. Analysis and comparison of our theoretical and experimental device results in structures where Auger suppression
was realized are also presented. 相似文献
3.
Nonequilibrium Operation of Arsenic Diffused Long-Wavelength Infrared HgCdTe Photodiodes 总被引:1,自引:0,他引:1
Priyalal S. Wijewarnasuriya P.Y. Emelie Arvind D’Souza Gregory Brill Maryn G. Stapelbroek Silviu Velicu Yuanping Chen Chris Grein Sivalingam Sivananthan Nibir K. Dhar 《Journal of Electronic Materials》2008,37(9):1283-1290
We demonstrated a device with a unique planar architecture using a novel approach for obtaining low arsenic doping concentrations
in long-wavelength (LW) HgCdTe on CdZnTe substrates. HgCdTe materials were grown by molecular beam epitaxy (MBE). We fabricated
a p-on-n structure that we term P
+/π/N
+ where the symbol “π” is to indicate a drastically reduced extrinsic p-type carrier concentration (on the order of mid 1015 cm−3); P
+ and N
+ denote a higher doping density, as well as a higher energy gap, than the photosensitive base π-region. Fabricated devices
indicated that Auger suppression is seen in the P
+/π/N
+ architecture at temperatures above 130 K and we obtained a saturation current on the order of 3 mA on 250-μm-diameter devices at 300 K with Auger suppression. Data shows that about a 50% reduction in dark current is achieved at 300 K
due to Auger suppression. The onset of Auger suppression voltage is 450 mV at 300 K and 100 mV at 130 K. Results indicate
that a reduction of the series resistance could reduce this further. A principal challenge was to obtain low p-type doping levels in the π-region. This issue was overcome using a novel deep diffusion process, thereby demonstrating successfully
low-doped p-type HgCdTe in MBE-grown material. Near-classical spectral responses were obtained at 250 K and at 100 K with cut-off wavelengths
of 7.4 μm and 10.4 μm, respectively. At 100 K, the measured non-antireflection-coated quantum efficiency was 0.57 at 0.1 V under backside illumination.
Received November 7, 2007; accepted March 19, 2008 相似文献
4.
M.F. Vilela D.D. Lofgreen E.P.G. Smith M.D. Newton G.M. Venzor J.M. Peterson J.J. Franklin M. Reddy Y. Thai E.A. Patten S.M. Johnson M.Z. Tidrow 《Journal of Electronic Materials》2008,37(9):1465-1470
Long-wavelength infrared (LWIR) HgCdTe p-on-n double-layer heterojunctions (DLHJs) for infrared detector applications have been grown on 100 mm Ge (112) substrates by
molecular beam epitaxy (MBE). The objective of this current work was to grow our baseline p-on-n DLHJ detector structure (used earlier on Si substrates) on 100 mm Ge substrates in the 10 μm to 11 μm LWIR spectral region, evaluate the material properties, and obtain some preliminary detector performance data. Material
characterization techniques included are X-ray rocking curves, etch pit density (EPD) measurements, compositional uniformity
determined from Fourier-transform infrared (FTIR) transmission, and doping concentrations determined from secondary-ion mass
spectroscopy (SIMS). Detector properties include resistance-area product (RoA), spectral response, and quantum efficiency.
Results of LWIR HgCdTe detectors and test structure arrays (TSA) fabricated on both Ge and silicon (Si) substrates are presented
and compared. Material properties demonstrated include X-ray full-width of half-maximum (FWHM) as low as 77 arcsec, typical
etch pit densities in mid 106 cm−2 and wavelength cutoff maximum/minimum variation <2% across the full wafer. Detector characteristics were found to be nearly
identical for HgCdTe grown on either Ge or Si substrates. 相似文献
5.
Accurate Simulation of Temperature-Dependent Dark Current
in HgCdTe Infrared Detectors Assisted by Analytical Modeling 总被引:3,自引:0,他引:3
Weida Hu Xiaoshuang Chen Zhenhua Ye Jing Zhang Fei Yin Chun Lin Zhifeng Li Wei Lu 《Journal of Electronic Materials》2010,39(7):981-985
Resistance–voltage curves of n
+-on-p Hg1−x
Cd
x
Te infrared photodiodes were measured in the temperature range of 60 K to 120 K. Characteristics obtained experimentally were
fitted by an improved simultaneous-mode nonlinear fitting process. Based on the extracted parameters, an efficient numerical
sim- ulation approach has been developed by inserting trap-assisted and band-to-band tunneling models into continuity equations
as generation–recombination processes. Simulated dark-current characteristics were found to be in good agreement with the
experimental data, demonstrating the validity of the nonlinear fitting process. Our work presents an efficient method for
dark-current simulations over a wide range of temperatures and bias voltages, which is important for investigating mechanisms
of carrier transport across the HgCdTe junction. 相似文献
6.
Anne M. Itsuno Jamie D. Phillips Silviu Velicu 《Journal of Electronic Materials》2012,41(10):2886-2892
A unipolar mercury cadmium telluride (HgCdTe) NBνN infrared (IR) device architecture is analyzed by physics-based numerical device simulations. The device structure is predicted to suppress Shockley–Read–Hall (SRH) and Auger generation–recombination (G–R) processes, while also providing a simplified fabrication process by eliminating p-type doping requirements. The performance characteristics of mid- and long-wavelength infrared (MWIR: λ c?=?5?μm; LWIR: λ c?=?12?μm) NBνN devices are calculated and compared with those of nBn and double-layer planar heterostructure (DLPH) devices. Theoretical dark current density (J dark) values of the MWIR and LWIR NBνN devices are lower by an order of magnitude or more for temperatures between 50?K and 225?K. Calculated peak detectivity (D *) values of 6.01?× 1014?cm?Hz0.5/W to 2.36?×?1010?cm?Hz0.5/W for temperatures from 95?K to 225?K, and 2.37?×?1014?cm?Hz0.5/W to 2.27?×?1011?cm?Hz0.5/W for temperatures from 50?K to 95?K are observed for MWIR and LWIR NBνN structures, respectively. A component of the NBνN structure, embodied in a unipolar MWIR nBn device, is also fabricated to experimentally demonstrate selective carrier extraction. 相似文献
7.
The general approach and effects of nonequilibrium operation of Auger suppressed HgCdTe infrared detectors 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 accurately model the devices, including self-consistent, steady-state solutions of Poisson’s equation and the carrier
continuity equations for carrier densities, Boltzmann transport theory, and published models for recombination/generation
processes in HgCdTe. Numerical simulations are used to optimize the material structure and doping levels for an Auger suppressed
detector with λ
c
= 5.5 μm at 200 K. The optimized detector structure with step doping and compositional profiles is then compared to a device with
realistic gradient doping and compositional profiles. 相似文献
8.
P.Y. Emelie E. Cagin J. Siddiqui J.D. Phillips C. Fulk J. Garland S. Sivananthan 《Journal of Electronic Materials》2007,36(8):841-845
The electrical characteristics of organic (3,4-polyethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) contacts to
HgCdTe are studied as a potential alternative to metal/HgCdTe contacts. The use of organic PEDOT:PSS contacts offers the potential
for an improved contact technology for HgCdTe IR detector arrays. In this work, PEDOT:PSS contacts are deposited on n-type and p-type HgCdTe epilayers by spin coating and patterned using a metal mask. Current-voltage (I-V) characteristics are measured
on these contacts, showing nearly ohmic behavior. The temperature dependence of I-V characteristics (T = 40–300 K) shows increased resistance for decreasing temperature, consistent with the temperature dependence of HgCdTe resistivity,
suggesting that the I-V characteristics are primarily dominated by the HgCdTe material. 相似文献
9.
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
10.
M.F. Vilela S.F. Harris R.E. Kvaas A.A. Buell M.D. Newton K.R. Olsson D.D. Lofgreen S.M. Johnson 《Journal of Electronic Materials》2009,38(8):1755-1763
In this paper, we show the versatility of using molecular-beam epitaxy (MBE) for the growth of the mercury cadmium telluride
(HgCdTe) system. Abrupt composition profiles, changes in doping levels or switching doping types are easily performed. It
is shown that high-quality material is achieved with Hg(1–x)Cd
x
Te grown by MBE from a cadmium mole fraction of x = 0.15 to x = 0.72. Doping elements incorporation as low as 1015 cm−3 for both n-type and p-type material as well as high incorporation levels >1018 cm−3 for both carrier types were achieved. X-ray curves, secondary-ion mass spectrometry (SIMS) data, Hall data, the influence
of doping incorporation with cadmium content and growth rate, etch pit density (EPD), composition uniformity determined from
Fourier-transform infrared (FTIR) transmission spectro- scopy, and surface defect maps from low to high x values are presented to illustrate the versatility and quality of HgCdTe material grown by MBE. All data presented in this
work are from layers grown on silicon (112) substrate. 相似文献
11.
Junction Stability in Ion-Implanted Mercury Cadmium Telluride 总被引:1,自引:0,他引:1
Ion implantation into HgCdTe results in the production of Hg interstitials, which can be subsequently driven into the HgCdTe
by an annealing process. This diffusive drive-in of the Hg interstitials fills vacancies and kicks out group I impurities
and results in the formation of an n–p junction. In this work we report on the production of interstitials during baking subsequent to the ion implantation process.
Various concentrations of metal vacancies were first introduced into mid-wavelength infrared (MWIR, 3 μm to 5 μm) HgCdTe by annealing under tellurium-saturated conditions at various temperatures. Baking subsequent to planar implantation
of boron produced n–p junctions whose depths were measured by defect etching. The results were modeled using a simple diffusion limited model from
a fixed surface concentration. The surface concentration was allowed to decrease exponentially to zero after a time, found
to be of the order of ∼80 h to 150 h. Exhaustion of the interstitials sources produced by the implantation was nearly complete
after ∼400 h. The total number of mercury interstitials produced was approximately 50% of the implant dosage. 相似文献
12.
基于当前红外探测器技术的发展方向,从高工作温度红外探测器应用需求的角度分析了碲镉汞高工作温度红外探测器在组件重量、外形尺寸、功耗、环境适应性及可靠性方面的优势。总结了欧美等发达国家在碲镉汞高工作温度红外探测器研究方面的技术路线及研究现状。从器件暗电流和噪声机制的角度分析了碲镉汞光电器件在不同工作温度下的暗电流和噪声变化情况及其对器件性能的影响;总结了包括基于工艺优化的Hg空位p型n-on-p结构碲镉汞器件、基于In掺杂p-on-n结构和Au掺杂n-on-p结构的非本征掺杂碲镉汞高工作温度器件、基于nBn势垒阻挡结构的碲镉汞高工作温度器件及基于吸收层热激发载流子俄歇抑制的非平衡模式碲镉汞高工作温度器件在内的不同技术路线碲镉汞高工作温度器件的基本原理,对比分析了不同技术路线碲镉汞高工作温度器件的性能及探测器制备的技术难点。在综合分析不同技术路线高温器件性能与技术实现难度的基础上展望了碲镉汞高工作温度器件技术未来的发展方向,认为基于低浓度掺杂吸收层的全耗尽结构器件具备更好的发展潜力。 相似文献
13.
A. M. Itsuno P. Y. Emelie J. D. Phillips S. Velicu C. H. Grein P. S. Wijewarnasuriya 《Journal of Electronic Materials》2010,39(7):945-950
Controllable p-type doping at low concentrations is desired for multilayer HgCdTe samples in a P
+/π/N
+ structure due to the promise of suppressing Auger processes, and ultimately reduced dark current for infrared detectors operating
at a given temperature. In this study, a series of arsenic implantation and annealing experiments have been conducted to study
diffusion at low Hg partial pressure with the goal of achieving effective control over dopant profiles at low concentration.
Arsenic dopant profiles were measured by secondary ion mass spectroscopy (SIMS), where diffusion coefficients were extracted
with values ranging between 3.35 × 10−16 cm2 s−1 and 6 × 10−14 cm2 s−1. Arsenic diffusion coefficients were found to vary strongly with Hg partial pressure and HgCdTe alloy composition, corresponding
to variations in Hg vacancy concentration. 相似文献
14.
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
15.
Y. Isoda S. Tada T. Nagai H. Fujiu Y. Shinohara 《Journal of Electronic Materials》2010,39(9):1531-1535
Mg2Si1−x
Sn
x
-system solid solutions are ecofriendly semiconductors that are promising materials for thermoelectric generators in the middle
temperature range. To produce a thermoelectric device, high-performance p- and n-type materials must be balanced. In this paper, p-type Mg2.00Si0.25Sn0.75 with Li and Ag double doping was prepared by the liquid–solid reaction method and hot-pressing. Effects of Li and Ag double
doping on thermoelectric properties were investigated in the temperature range from room temperature to 850 K. All sintered
compacts were identified as single-phase solid solutions with anti-fluorite structure. The carrier concentration increased
with the double doping. The temperature dependence of resistivity of the double-doped samples was similar to that of a metal.
The seebeck coefficient increased with temperature to a maximum value and then decreased in the intrinsic region. Thermal
conductivity decreased linearly with increasing temperature, reaching a minimum near the intrinsic region, and then increased
rapidly because of the contribution of the bipolar component. The dimensionless figure of merit reached 0.32 at 610 K for
Mg2.00Si0.25Sn0.75 double-doped with Li-5000 ppm and Ag-20000 ppm. 相似文献
16.
Single crystal diffraction measurements were successfully carried out for spherical fine grains grown as single crystals of
0.05–0.2 mm in diameter. Local modulations in the silicon layers were also observed by means of high-resolution electron microscopy.
The metallic tin–flux technique was used for crystal growth. The Fourier synthesis and maximum entropy method (MEM) were applied
to x-ray diffraction data to obtain electron density distribution maps. Mn4Si7 is one of the most promising p-type thermoelectrics useable from 400 K to 700 K. The crystal structure is described in terms of a chimney-ladder structure.
The doping effect, by which the system becomes n-type and a structure modulation occurs, was reported by our group previously. The resultant electron density maps were compared
with those from the band calculation. The MEM calculation shows the displacement of silicon positions. 相似文献
17.
T.J. de Lyon R.D. Rajavel A.T. Hunter J.E. Jensen M.D. Jack S.L. Bailey R.E. Kvaas V.K. Randall S.M. Johnson 《Journal of Electronic Materials》2008,37(9):1420-1425
An initial investigation of the use of atomic nitrogen for controlled p-type doping of wide-bandgap Hg0.3Cd0.7Te (x = 0.7) is reported. Mixtures of argon and nitrogen, ranging in nitrogen concentration from 0.1% to 100%, have been utilized
to demonstrate well-controlled nitrogen incorporation in the 1016 cm−3 to 1020 cm−3 range using total gas flow rates of 0.3 sccm to 4.0 sccm and radiofrequency (RF) powers of 100 W to 400 W. Nitrogen doping
exhibits several desirable attributes including abrupt turn-on and turn-off and minimal sensitivity to variations in growth
temperature and HgCdTe composition, with no negative effects on HgCdTe dislocation density and morphology. Preliminary electrical
measurements indicate primarily n-type behavior in the 1014 cm−3 to 1015 cm−3 range in as-grown x = 0.7 HgCdTe and CdTe films doped with nitrogen at 1018 cm−3 to 1020 cm−3 concentrations, while ZnTe films have exhibited p-type electrical activity with hole concentrations approaching 1020 cm−3. 相似文献
18.
Sung-Do Kwon Byeong-kwon Ju Seok-Jin Yoon Jin-Sang Kim 《Journal of Electronic Materials》2009,38(7):920-924
Bismuth–antimony–telluride based thin film materials were grown by metal organic vapor phase deposition (MOCVD). A planar-type
thermoelectric device was fabricated with p-type Bi0.4Sb1.6Te3 and n-type Bi2Te3 thin films. The generator consisted of 20 pairs of p-type and n-type legs. We demonstrated complex structures of different conduction types of thermoelectric elements on the same substrate
using two separate deposition runs of p-type and n-type thermoelectric materials. To demonstrate power generation, we heated one side of the sample with a heating block and
measured the voltage output. An estimated power of 1.3 μW was obtained for the temperature difference of 45 K. We provide a promising procedure for fabricating thin film thermoelectric
generators by using MOCVD grown thermoelectric materials that may have a nanostructure with high thermoelectric properties. 相似文献
19.
E. A. Patten P. M. Goetz M. F. Vilela K. Olsson D. D. Lofgreen J. G. Vodicka S. M. Johnson 《Journal of Electronic Materials》2010,39(10):2215-2219
HgCdTe grown on large-area Si substrates allows for larger array formats and potentially reduced focal-plane array (FPA) cost
compared with smaller, more expensive CdZnTe substrates. The goal of this work is to evaluate the use of HgCdTe/Si for mid-wavelength/long-wavelength
infrared (MWIR/LWIR) dual-band FPAs. A series of MWIR/LWIR dual-band HgCdTe triple-layer n-P-n heterojunction (TLHJ) device structures were grown by molecular-beam epitaxy (MBE) on 100-mm (211)Si substrates. The wafers
showed low macrodefect density (<300 cm−2) and was processed into 20-μm-unit-cell 640 × 480 detector arrays which were mated to dual-band readout integrated circuits (ROICs) to produce FPAs. The
measured 80-K cutoff wavelengths were 5.5 μm for MWIR and 9.4 μm for LWIR, respectively. The FPAs exhibited high pixel operabilities in each band, with noise equivalent differential temperature
(NEDT) operabilities of 99.98% for the MWIR band and 99.6% for the LWIR band demonstrated at 84 K. 相似文献
20.
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