共查询到20条相似文献,搜索用时 0 毫秒
1.
J. P. Zanatta G. Badano P. Ballet C. Largeron J. Baylet O. Gravrand J. Rothman P. Castelein J. P. Chamonal A. Million G. Destefanis S. Mibord E. Brochier P. Costa 《Journal of Electronic Materials》2006,35(6):1231-1236
The Leti-Lir has studied II–VI compounds for infrared (IR) detection for more than 20 years. The need to reduce the production
cost of IR focal plane arrays (FPAs) sparked the development of heteroepitaxy on large-area substrates. Germanium has been
chosen as the heterosubstrate for the third generation of IR detectors. First, we report on the progress achieved in HgCdTe
growth on 3-in. and 4-in. (211)B CdTe/Ge. Then, we discuss the choice of a new machine for larger size and better homogeneity.
Finally, we present the latest results on third-generation IR multicolor and megapixel devices. First-time results regarding
a middle wavelength infrared (MWIR) dual-band FPA, with a reduced pitch of 25 μm, and a MWIR 1,280×1,024 FPA will be shown.
Both detectors are based on molecular beam epitaxy (MBE)-grown HgCdTe on Ge. The results shown validate the choice of Ge as
the substrate for third-generation detectors. 相似文献
2.
Dual-band infrared detectors made on high-quality HgCdTe epilayers grown by molecular beam epitaxy on CdZnTe or CdTe/Ge substrates 总被引:2,自引:0,他引:2
P. Ballet F. Noël F. Pottier S. Plissard J. P. Zanatta J. Baylet O. Gravrand E. De Borniol S. Martin P. Castelein J. P. Chamonal A. Million G. Destefanis 《Journal of Electronic Materials》2004,33(6):667-672
In this paper, we present all the successive steps for realizing dual-band infrared detectors operating in the mid-wavelength
infrared (MWIR) band. High crystalline quality HgCdTe multilayer stacks have been grown by molecular beam epitaxy (MBE) on
CdZnTe and CdTe/Ge substrates. Material characterization in the light of high-resolution x-ray diffraction (HRXRD) results
and dislocation density measurements are exposed in detail. These characterizations show some striking differences between
structures grown on the two kinds of substrates. Device processing and readout circuit for 128×128 focal-plane array (FPA)
fabrication are described. The electro-optical characteristics of the devices show that devices grown on Ge match those grown
on CdZnTe substrates in terms of responsivity, noise measurements, and operability. 相似文献
3.
J. N. Johnson L. A. Almeida M. Martinka J. D. Benson J. H. Dinan 《Journal of Electronic Materials》1999,28(6):817-820
Without any additional preparation, Cd1−yZnyTe (211)B (y∼3.5%) wafers were cleaned by exposure to an electron cyclotron resonance (ECR) Ar/H2 plasma and used as substrates for HgCdTe molecular beam epitaxy. Auger electron spectra were taken from as-received wafers,
conventionally prepared wafers (bromine: methanol etching, followed by heating to 330–340°C), and wafers prepared under a
variety of ECR process conditions. Surfaces of as-received wafers contained ∼1.5 monolayers of contaminants (oxygen, carbon,
and chlorine). Conventionally prepared wafers had ∼1/4 monolayer of carbon contamination, as well as excess tellurium and/or
excess zinc depending on the heating process used. Auger spectra from plasma-treated CdZnTe wafers showed surfaces free from
contamination, with the expected stoichiometry. Stoichiometry and surface cleanliness were insensitive to the duration of
plasma exposure (2–20 s) and to changes in radio frequency input power (20–100 W). Reflection high energy electron diffraction
patterns were streaked indicating microscopically smooth and ordered surfaces. The smoothness of plasma-etched CdZnTe wafers
was further confirmed ex situ using interferometric microscopy. Surface roughness values of ∼0.4 nm were measured. Characteristics of HgCdTe epilayers
deposited on wafers prepared with plasma and conventional etching were found to be comparable. For these epilayers, etch pit
densities on the order of 105 cm−2 have been achieved. ECR Ar/H2 plasma cleaning is now utilized at Night Vision and Electronic Sensors Directorate as the baseline CdZnTe surface preparation
technique. 相似文献
4.
Owen K. Wu D. M. Jamba G. S. Kamath G. R. Chapman S. M. Johnson J. M. Peterson K. Kosai C. A. Cockrum 《Journal of Electronic Materials》1995,24(5):423-429
HgCdTe MBE technology is becoming a mature growth technology for flexible manufacturing of short-wave, medium-wave, long-wave,
and very long-wave infrared focal plane arrays. The main reason that this technology is getting more mature for device applications
is the progress made in controlling the dopants (both n-type and p-type in-situ) and the success in lowering the defect density
to less than 2 x 105/cm2 in the base layer. In this paper, we will discuss the unique approach that we have developed for growing As-doped HgCdTe
alloys with cadmium arsenide compound. Material properties including composition, crystallinity, dopant activation, minority
carrier lifetime, and morphology are also discussed. In addition, we have fabricated several infrared focal plane arrays using
device quality double layers and the device results are approaching that of the state-of-the-art liquid phase epitaxy technology. 相似文献
5.
We study the adsorption of Hg on CdTe(211)B using an 88-wavelength spectroscopic ellipsometer mounted on a commercial, molecular
beam epitaxy (MBE) chamber. A detailed analysis of the pseudo-dielectric function shows that Hg is present at the surface
both in chemisorbed and physisorbed form. Effective medium models for a mixture of chemisorbed and physisorbed Hg on the microscopically
rough CdTe surface could not fit our data. However, a proposed model in which a partial layer of physisorbed Hg sits on top
of a partial layer of chemisorbed Hg fits the measured pseudo-dielectric function well and yields precise values for the thicknesses
of the chemisorbed and the physisorbed Hg layers. These values change in the expected manner as a function of Hg flux, temperature,
and Te coverage. An analysis of the uncertainty in the measured thicknesses is carried out in detail, and a study of the limitations
of the ellipsometer used for this study is presented. The effects of these limitations on the precision and accuracy of in-situ
data are enumerated. 相似文献
6.
J. N. Johnson L. A. Almeida J. D. Benson J. H. Dinan M. Martinka 《Journal of Electronic Materials》1998,27(6):657-660
CdZnTe wafers were inserted into a multi-chamber processing facility without prior preparation, cleaned by exposure to an
electron cyclotron resonance Ar/H2 plasma, and used as substrates for molecular beam epitaxy of HgCdTe. Changes induced in the wafer near-surface region during
the cleaning step were monitored using in situ spectroscopic ellipsometry. Ellipsometric data were subsequently modeled to provide the time evolution of the thickness of
a native overlayer. Auger electron spectra were consistent with surfaces free of residual contamination and which had the
stoichiometry of the underlying bulk. Surface roughness values of 0.4 nm were obtained ex situ using interferometric microscopy. Electron diffraction patterns of plasma prepared wafers heated to 185°C (the temperature
required for HgCdTe molecular beam epitaxy) were streaked. Structural and electrical characteristics of epilayers grown on
these substrates were found to be comparable to those deposited on wafers prepared using a conventional wet chemical process.
This demonstrates an important step in an all-vacuum approach to HgCdTe detector fabrication. 相似文献
7.
A Hg1-xCdxTe growth method is presented for molecular beam epitaxy, which precisely controls growth conditions to routinely obtain device
quality epilayers at a certain specific composition. This method corrects the fluctuation in composition x for run-to-run
growth by feedback from the x value for the former growth to the fluxes from CdTe and Te cells. We achieved standard deviation
Δx/ x of 3.3% for 13 samples grown consecutively. A substrate temperature drop was found during growth, which considerably
degrades the crystal quality of epilayers. In this method, this drop is greatly diminished by covering the holder surface
with a heavily doped Si wafer. Finally, etch pit density of 4 x 104 cm-2 and full width at half-maximum of 12 arc-s for the x-ray double-crystal rocking curve were obtained as the best values. 相似文献
8.
Heteroepitaxy of HgCdTe(112) infrared detector structures on Si(112) substrates by molecular-beam epitaxy 总被引:4,自引:0,他引:4
T. J. De Lyon R. D. Rajavel J. E. Jensen O. K. Wu S. M. Johnson C. A. Cockrum G. M. Venzor 《Journal of Electronic Materials》1996,25(8):1341-1346
High-quality, single-crystal epitaxial films of CdTe(112)B and HgCdTe(112)B have been grown directly on Si(112) substrates
without the need for GaAs interfacial layers. The CdTe and HgCdTe films have been characterized with optical microscopy, x-ray
diffraction, wet chemical defect etching, and secondary ion mass spectrometry. HgCdTe/Si infrared detectors have also been
fabricated and tested. The CdTe(112)B films are highly specular, twin-free, and have x-ray rocking curves as narrow as 72
arc-sec and near-surface etch pit density (EPD) of 2 × 106 cm−2 for 8 μm thick films. HgCdTe(112)B films deposited on Si substrates have x-ray rocking curve FWHM as low as 76 arc-sec and
EPD of 3-22 × 106 cm−2. These MBE-grown epitaxial structures have been used to fabricate the first high-performance HgCdTe IR detectors grown directly
on Si without use of an intermediate GaAs buffer layer. HgCdTe/Si infrared detectors have been fabricated with 40% quantum
efficiency and R0A = 1.64 × 104 Ωm2 (0 FOV) for devices with 7.8 μm cutoff wavelength at 78Kto demonstrate the capability of MBE for growth of large-area HgCdTe
arrays on Si. 相似文献
9.
Molecular beam epitaxy HgCdTe growth-induced void defects and their effect on infrared photodiodes 总被引:3,自引:0,他引:3
J. M. Arias M. Zandian J. Bajaj J. G. Pasko L. O. Bubulac S. H. Shin R. E. De Wames 《Journal of Electronic Materials》1995,24(5):521-524
We have carried out a study and identified that MBE HgCdTe growth-induced void defects are detrimental to long wavelength
infrared photodiode performance. These defects were induced during nucleation by having surface growth conditions deficient
in Hg. Precise control and reproducibility of the CdZnTe surface temperature and beam fluxes are required to minimize such
defects. Device quality material with void defect concentration values in the low 102 cm2 range were demonstrated. 相似文献
10.
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
11.
L. O. Bubulac W. E. Tennant J. G. Pasko L. J. Kozlowski M. Zandian M. E. Motamedi R. E. De Wames J. Bajaj N. Nayar W. V. McLevige N. S. Gluck R. Melendes D. E. Cooper D. D. Edwall J. M. Arias R. Hall A. I. D’souza 《Journal of Electronic Materials》1997,26(6):649-655
Short wave infrared (SWIR) devices have been fabricated using Rockwell’s double layer planar heterostructure (DLPH) architecture
with arsenic-ion implanted junctions. Molecular beam epitaxially grown HgCdTe/CdZnTe multilayer structures allowed the thin,
tailored device geometries (typical active layer thickness was ∼3.5 μm and cap layer thickness was ∼0.4 μm) to be grown. A
planar-mesa geometry that preserved the passivation advantages of the DLPH structure with enhanced optical collection improved
the performance. Test detectors showed Band 7 detectors performing near the radiative limit (∼3-5X below theory). Band 5 detector
performance was ∼4-50X lower than radiative limited performance, apparently due to Shockley-Hall-Read recombination. We have
fabricated SWIR HgCdTe 256 × 12 × 2 arrays of 45 um × 45 μm detector on 45 μm × 60 μm centers and with cutoff wavelength which
allows coverage of the Landsat Band 5 (1.5−1.75 μm) and Landsat Band 7 (2.08−2.35 μm) spectral regions. The hybridizable arrays
have four subarrays, each having a different detector architecture. One of the Band 7 hybrids has demonstrated performance
approaching the radiative theoretical limit for temperatures from 250 to 295K, consistent with test results. D* performance
at 250K of the best subarray was high, with an operability of ∼99% at 1012 cm Hz1/2/W at a few mV bias. We have observed 1/f noise below 8E-17 AHz 1/2 at 1 Hz. Also for Band 7 test structures, Ge thin film diffractive microlenses fabricated directly on the back side of the
CdZnTe substrate showed the ability to increase the effective collection area of small (nominally <20 μm μm) planar-mesa diodes
to the microlens size of 48 urn. Using microlenses allows array performance to exceed 1-D theory up to a factor of 5. 相似文献
12.
S. M. Johnson A. A. Buell M. F. Vilela J. M. Peterson J. B. Varesi M. D. Newton G. M. Venzor R. E. Bornfreund W. A. Radford E. P. G. Smith J. P. Rosbeck T. J. De Lyon J. E. Jensen V. Nathan 《Journal of Electronic Materials》2004,33(6):526-530
The heteroepitaxial growth of HgCdTe on large-area Si substrates is an enabling technology leading to the production of low-cost,
large-format infrared focal plane arrays (FPAs). This approach will allow HgCdTe FPA technology to be scaled beyond the limitations
of bulk CdZnTe substrates. We have already achieved excellent mid-wavelength infrared (MWIR) and short wavelength infrared
(SWIR) detector and FPA results using HgCdTe grown on 4-in. Si substrates using molecular beam epitaxy (MBE), and this work
was focused on extending these results into the long wavelength infrared (LWIR) spectral regime. A series of nine p-on-n LWIR
HgCdTe double-layer heterojunction (DLHJ) detector structures were grown on 4-in. Si substrates. The HgCdTe composition uniformity
was very good over the entire 4-in. wafer with a typical maximum nonuniformity of 2.2% at the very edge of the wafer; run-to-run
composition reproducibility, realized with real-time feedback control using spectroscopic ellipsometry, was also very good.
Both secondary ion mass spectrometry (SIMS) and Hall-effect measurements showed well-behaved doping and majority carrier properties,
respectively. Preliminary detector results were promising for this initial work and good broad-band spectral response was
demonstrated; 61% quantum efficiency was measured, which is very good compared to a maximum allowed value of 70% for a non-antireflection-coated
Si surface. The R0A products for HgCdTe/Si detectors in the 9.6-μm and 12-μm cutoff range were at least one order of magnitude below typical
results for detectors fabricated on bulk CdZnTe substrates. This lower performance was attributed to an elevated dislocation
density, which is in the mid-106 cm−2 range. The dislocation density in HgCdTe/Si needs to be reduced to <106 cm−2 to make high-performance LWIR detectors, and multiple approaches are being tried across the infrared community to achieve
this result because the technological payoff is significant. 相似文献
13.
Molecular beam epitaxy growth of high-quality HgCdTe LWIR layers on polished and repolished CdZnTe substrates 总被引:2,自引:0,他引:2
R. Singh S. Velicu J. Crocco Y. Chang J. Zhao L. A. Almeida J. Markunas A. Kaleczyc J. H. Dinan 《Journal of Electronic Materials》2005,34(6):885-890
We report here molecular beam epitaxy (MBE) mercury cadmium telluride (HgCdTe) layers grown on polished and repolished substrates
that showed state-of-the-art optical, structural, and electrical characteristics. Many polishing machines currently available
do not take into account the soft semiconductor materials, CdZnTe (CZT) being one. Therefore, a polishing jig was custom designed
and engineered to take in account certain physical parameters (pressure, substrate rotational frequency, drip rate of solution
onto the polishing pad, and polishing pad rotational velocity). The control over these parameters increased the quality, uniformity,
and the reproducibility of each polish. EPIR also investigated several bromine containing solutions used for polishing CZT.
The concentration of bromine, as well as the mechanical parameters, was varied in order to determine the optimal conditions
for polishing CZT. 相似文献
14.
利用全固态分子束外延(MBE)方法在Ge(100)衬底上异质外延GaAs薄膜,并通过高能电子衍射(RHEED)、高分辨X射线衍射(XRD),原子力显微镜等手段研究了不同生长参数对外延层的影响.RHEED显示在较高的生长温度或较低的生长速率下,低温GaAs成核层呈现层状生长模式.同时降低生长温度和生长速率会使GaAs薄膜的XRD摇摆曲线半高宽(FWHM)减小,并降低外延层表面的粗糙度,这主要是由于衬底和外延薄膜之间的晶格失配度减小的结果. 相似文献
15.
R. M. Sieg S. A. Ringel S. M. Ting E. A. Fitzgerald R. N. Sacks 《Journal of Electronic Materials》1998,27(7):900-907
The nucleation and growth of GaAs films on offcut (001) Ge wafers by solid source molecular beam epitaxy (MBE) is investigated,
with the objective of establishing nucleation conditions which reproducibly yield GaAs films which are free of antiphase domains
(APDs) and which have suppressed Ge outdiffusion into the GaAs layer. The nucleation process is monitored by in-situ reflection high energy electron diffraction and Auger electron spectroscopy. Several nucleation variables are studied, including
the state of the initial Ge surface (single-domain 2×1 or mixed-domain 2×1:1×2), the initial prelayer (As, Ga, or mixed),
and the initial GaAs growth temperature (350 or 500°C). Conditions are identified which simultaneously produce APD-free GaAs
layers several microns in thickness on Ge wafers with undetectable Ge outdiffusion and with surface roughness equivalent to
that of GaAs/GaAs homoepitaxy. APD-free material is obtained using either As or Ga nucleation layers, with the GaAs domain
dependent upon the initial exposure chemical species. Key growth steps for APD-free GaAs/Ge growth by solid source MBE include
an epitaxial Ge buffer deposited in the MBE chamber to bury carbon contamination from the underlying Ge wafer, an anneal of
the Ge buffer at 640°C to generate a predominantly double atomic-height stepped surface, and nucleation of GaAs growth by
a ten monolayer migration enhanced epitaxy step initiated with either pure As or Ga. We identify this last step as being responsible
for blocking Ge outdiffusion to below 1015 cm−3 within 0.5 microns of the GaAs/Ge interface. 相似文献
16.
Microstructural and optical characterization of CdTe(211)B/ZnTe/Si(211) grown by molecular beam epitaxy 总被引:2,自引:0,他引:2
S. Rujirawat David J. Smith J. P. Faurie G. Neu V. Nathan S. Sivananthan 《Journal of Electronic Materials》1998,27(9):1047-1052
CdTe layers have been grown by molecular beam epitaxy on 3 inch nominal Si(211) under various conditions to study the effect
of growth parameters on the structural quality. The microstructure of several samples was investigated by high resolution
transmission electron microscopy (HRTEM). The orientation of the CdTe layers was affected strongly by the ZnTe buffer deposition
temperature. Both single domain CdTe(133)B and CdTe(211)B were obtained by selective growth of ZnTe buffer layers at different
temperatures. We demonstrated that thin ZnTe buffer layers (<2 nm) are sufficient to maintain the (211) orientation. CdTe
deposited at ∼300°C grows with its normal lattice parameter from the onset of growth, demonstrating the effective strain accommodation
of the buffer layer. The low tilt angle (<1°) between CdTe[211] and Si[211] indicates that high miscut Si(211) substrates
are unnecessary. From low temperature photoluminescence, it is shown that Cd-substituted Li is the main residual impurity
in the CdTe layer. In addition, deep emission bands are attributed to the presence of AsTe and AgCd acceptors. There is no evidence that copper plays a role in the impurity contamination of the samples. 相似文献
17.
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
18.
Lijie Zhao J. S. Speck R. Rajavel J. Jensen D. Leonard T. Strand W. Hamilton 《Journal of Electronic Materials》2000,29(6):732-735
Transmission electron microscopy (TEM) was used to evaluate the microstructure of molecular beam epitaxy (MBE) grown (211)B
oriented HgCdTe films. TEM analysis of in-situ doped p-on-n and n-p-n device structures will be presented. Under fully optimized
growth conditions the substrate-epilayer interface is free of threading dislocations and twins, and a high degree of structural
integrity is retained throughout the entire device structure. However, under non-optimal growth conditions that employ high
Hg/Te flux ratios, twins can be generated in the p-type layer of p-on-n device structure, resulting in roughness and facetting
of the film surface. We propose a mechanism for twin formation that is associated with surface facetting. TEM evaluation of
voids, threading dislocations and Te-precipitates in HgCdTe films are also discussed. 相似文献
19.
Brett Z. Nosho John A. Roth John E. Jensen Le Pham 《Journal of Electronic Materials》2005,34(6):779-785
The fabrication of high-quality focal plane arrays from HgCdTe layers grown by molecular beam epitaxy (MBE) requires a high
degree of lateral uniformity in material properties such as the alloy composition, doping concentration, and defect density.
While it is well known that MBE source flux nonuniformity can lead to radial compositional variation for rotating substrates,
we have also found that composition can be affected significantly by lateral variations in substrate temperature during growth.
In diagnostic experiments, we systematically varied the substrate temperature during MBE and quantified the dependence of
HgCdTe alloy composition on substrate temperature. Based on these results, we developed a methodology to quickly and nondestructively
characterize MBE-grown layers using postgrowth spatial mapping of the cutoff wavelength from the Fourier transform infrared
(FTIR) transmission at 300 K, and we were able to obtain a quantitative relationship between the measured spatial variations
in cutoff and the substrate temperature lateral distribution during growth. We refined this methodology by more directly inferring
the substrate temperature distribution from secondary ion mass spectroscopy (SIMS) measurements of the As concentration across
a wafer, using the fact that the As incorporation rate in MBE-grown p-type layers is highly sensitive to substrate temperature.
Combining this multiple-point SIMS analysis with FTIR spatial mapping, we demonstrate how the relative contributions from
flux nonuniformity and temperature variations on the lateral composition uniformity can be separated. This capability to accurately
map the lateral variations in the substrate temperature has been valuable in optimizing the mounting and bonding of large
substrates for MBE growth, and can also be valuable for other aspects of MBE process development. 相似文献
20.
R. D. Rajavel D. Jamba O. K. Wu J. A. Roth P. D. Brewer J. E. Jensen C. A. Cockrum G. M. Venzor S. M. Johnson 《Journal of Electronic Materials》1996,25(8):1411-1415
A robust process has been developed for the reproducible growth of in-situ doped Hg1−xCdxTe:As alloys by molecular beam epitaxy. Net hole concentrations in excess of 5 x 1017 cm−3, with peak mobilities >200 cm2/Vs were measured in Hg0.74Cd0.26Te:As films. The p-type layers were twin-free and consistently exhibit narrow x-ray rocking curves (<40 arc sec). The reproducible
growth of small lots of p-on-n LWIR detector structures has been established. For a typical lot consisting of 13 layers, the
average x-value of the n-type base layer was 0.226 with a standard deviation of 0.003. The lateral compositional uniformity
across a 2.5 cm × 2.5 cm wafer was × = +- 0.0006. High performance p-on-n LWIR diodes were fabricated that exhibited RoAo values (0-fov at 78K) as large as 350 Q cm2 at 10.4 μm. 相似文献