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1.
Junction formation and stability in ion implanted mercury cadmium telluride critically depend on the ability to generate Hg
interstitials. The creation of Hg interstitials is found to strongly depend on the preferred lattice position of the element
implanted. Elements that substitute onto the cation sublattice create significantly more Hg interstitials than elements that
sit interstitially or on the anion sublattice. Recoils from implant damage also contribute to Hg interstitial formation in
heavier mass implants (Z ≥ of mass Zn), but appear to have negligible influence on interstitial generation in implants of
lighter ions. The combination of implanting ions of large mass and high solubility on the cation sublattice produces strong
Hg interstitial sources. Implants with these ions can form deep junctions even in heavily doped substrates. Junction stability
is also improved with the stronger interstitial source. 相似文献
2.
Donald C. Gillies 《Journal of Electronic Materials》1982,11(4):689-697
An electron microprobe analysis technique using energy dispersive spectrometry has been developed for rapid quantitative analysis
of mercury cadmium telluride at high spatial resolution. The results can demonstrate a difference of x in Hgl-xCdxTe of 0.002 between two locations as close as 5μm, the accuracy in x being dependent on how well determined are the composition
of the standards employed. Damage to the sample is limited by the low (lOkeV) excitation potential and low current used. The
method is applicable to bulk crystals and LPE grown material. 相似文献
3.
A. J. Stoltz M. Jaime-Vasquez J. D. Benson J. B. Varesi M. Martinka 《Journal of Electronic Materials》2006,35(6):1461-1464
High-density argon-hydrogen plasmas have been demonstrated to be very effective as etchants of CdTe, CdZnTe, and HgCdTe materials
for focal plane array applications. Understanding the physical, chemical, and electrical characteristics of these surfaces
is critical in elucidating the mechanisms of processing Hg1−xCdxTe. The ways in which these plasmas interact with HgCdTe, such as etch rates and loading, have been studied.1–11 However, little is known on how these plasmas affect the first few atomic layers of HgCdTe. In this study, the effects of
high-density plasmas on the surface of HgCdTe were examined. The combination of argon and hydrogen plasma etch leaves a well-ordered,
near-stoichiometric surface determined by both x-ray photoelectron spectroscopy and reflection high-energy electron diffraction
(RHEED). Starting with Hg0.78Cd0.22Te, we were able to produce surfaces with x=0.4 and a RHEED pattern sharp enough to measure 2×1 reconstruction. 相似文献
4.
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
5.
报道P-Hg_(1-x)Cd_xTe(x=0.234、N_A=4×10~(17)cm~(-3))MIS结构样品在电量子限条件下电子子能带朗道能级间磁光共振光跃迁实验结果。测量了不同光子能量和样品在不同表面电子浓度时子能带朗道能级间和自旋能级间的回旋共振和自旋共振。定量地证明了窄禁带半导体量子阱子能带朗道能级的移动和交叉效应,这一效应起源于表面势的反演不对称所导致的较强的表面电子自旋轨道相互作用。 相似文献
6.
T. Ohno H. Onose Y. Sugawara K. Asano T. Hayashi T. Yatsuo 《Journal of Electronic Materials》1999,28(3):180-185
The residual defects of Al+- or B+-implanted 4H-SiC were studied in combination with annealing temperature and implantation temperature using cross-sectional
transmission electron microscopy technique. Noticeable defects structure is not observed before post-implantation annealing.
But after annealing, a lot of black spots appear in the implanted layer. These black spots are composed of a dislocation loop,
parallel to {0001} of 4H-SiC, and strained area at the upper and lower sides of the dislocation loop. This defect structure
and its size do not depend on implantation temperature and implanted ion species. The size of defect area depends only on
post-implantation annealing temperature. The size grows, when post-annealing temperature is raised. 相似文献
7.
The surface roughness of inductively coupled plasma (ICP)-etched CdTe is greater than that of electron cyclotron resonance
(ECR)-etched CdTe. This greater roughness is undesirable for further processing of the material. Lower-frequency plasma excitation
from the ICP is more efficient at cracking hydrogen than the high-frequency plasma excitation of ECR. In binary semiconductors
it is important to balance removal of both constituents. Bombardment controls the removal of the metal constituent while hydrogen
removes the tellurium. Research performed with ECR plasma processing on HgCdTe shows that reducing the pressure can greatly
reduce hydrogen ionization. Applying this to ICP it can be shown that reduced pressure greatly improves the morphology of
CdTe. This balanced etching also greatly improves etch rate and selectivity of HgCdTe. 相似文献
8.
A. J. Stoltz J. D. Benson J. B. Varesi M. Martinka M. J. Sperry A. W. Kaleczyc L. A. Almeida P. R. Boyd J. H. Dinan 《Journal of Electronic Materials》2004,33(6):684-689
It has been observed in semiconductor processing that the etch rates for materials subjected to an electron-cyclotron resonance
(ECR) plasma change with the total sample area. This phenomenon is known as loading. Loading effects can result in pattern
definition errors during micromachining. In argon/hydrogen plasmas, designed to etch II–VI materials, loading appears to primarily
affect photoresist deterioration. Using an 80% argon-20% hydrogen gas chemistry optimized for HgCdTe, we observe a factor
of 2 variation in photoresist etch rate. Loading may also affect semiconductor etch rates to a lesser extent. The observed
trends suggest that radical changes in the plasma are the likely cause of this phenomenon. 相似文献
9.
S. P. Ahrenkiel M. W. Wanlass J. J. Carapella L. M. Gedvilas B. M. Keyes R. K. Ahrenkiel H. R. Moutinho 《Journal of Electronic Materials》2004,33(3):185-193
Low-bandgap, lattice-mismatched GaxIn1−xAs (GaInAs) grown using InAsyP1−y (InAsP) compositional-step grades on InP is a primary choice for lightabsorbing, active layers in high-efficiency thermophotovoltaic
(TPV) devices. The GaInAs/InAsP double heterostructures (DHs) show exceptional minority carrier lifetimes of up to several
microseconds. We have performed a characterization survey of 0.4–0.6-eV GaInAs/InAsP DHs using a variety of techniques, including
transmission electron microscopy (TEM). Dislocations are rarely observed to thread into the GaInAs active layers from the
InAsP buffer layers that terminate the graded regions. Nearly complete strain relaxation occurs in buried regions of the InAsP
grades. The buffer-layer strain prior to deposition of the active layer is virtually independent of the net misfit. Foreknowledge
of this buffer-layer strain is essential to correctly lattice match the buffer to the GaInAs active layer. 相似文献
10.
N. Nordell A. Schöner K. Rottner P. O. Å. Persson Q. Wahab L. Hultman M. K. Linnarsson E. Olsson 《Journal of Electronic Materials》1998,27(7):833-837
Implantation of B has been performed into an epitaxially grown layer of 6H SiC, at two different B concentrations, 2×1016 cm−3 and 2×1018 cm−3. Subsequently, an epitaxial layer was regrown on the B implanted layer. The samples were investigated by transmission electron
microscopy (TEM) and secondary ion mass spectrometry (SIMS). In the highly B-doped layers plate-like defects were found, associated
with large strain fields, and an increased B concentration. These defects were stable at the originally implanted region during
regrowth and at anneal temperatures up to 1700°C. In the samples implanted with the lower B concentration, no crystal defects
could be detected by TEM. No threading dislocations or other defects were observed in the regrown epitaxial layer, which shows
the possibility to grow a layer with high crystalline quality on B implanted 6H SiC. By SIMS, it was found that B piles up
at the interface to the regrown layer, which could be explained by enhanced diffusion from an increased concentration of point
defects created by implantation damage in the region. B is also spread out into the original crystal and in the regrown layer
at a concentration of below 2×1016 cm−3, with a diffusion constant estimated to 1.3×10−12 cm2s−1. This diffusion is most probably not driven by implantation damage, but by intrinsic defects in the grown crystal. Our investigation
shows that the combination of implantation and subsequent regrowth techniques could be used in SiC for building advanced device
structures, with the crystal quality in the regrown layer not being deteriorated by crystal defects in the implanted region.
A device process using B implantation and subsequent regrowth could on the other hand be limited by the diffusion of B. 相似文献
11.
Anthony J. Ciani Serdar Ogut Inder P. Batra Siva Sivananthan 《Journal of Electronic Materials》2005,34(6):868-872
The diffusion of defects is of great importance in nanoscale device fabrication, making it essential to understand theoretically
the microscopic mechanisms governing how native and dopant defects diffuse. To gain this insight, we have performed, for the
first time, ab initio density functional calculations to determine the diffusion barriers for multiple pathways of Au impurities and native species
in mercury cadmium telluride (MCT). We consider interstitial and vacancy-mediated diffusion mechanisms and calculate the corresponding
activation energies using ab initio pseudopotential total energy calculations. Depending on the stoichiometry, the activation energies for Hg self-diffusion
are calculated to range from 1.35 eV to 1.60 eV (interstitial mechanism) and from 1.60 eV to 1.85 eV (vacancy mechanism).
These theoretical values suggest that Hg self-diffusion is predominantly interstitial mediated, and are in good agreement
with existing experimental estimates, which suggest possible activation energies ranging from 1.05 eV to 1.75 eV. For Te self-diffusion
via the interstitial mechanism, the calculated activation energy ranging from 2.35 eV to 2.60 eV is also in good agreement
with the experimental estimates near 2.30 eV. For Au impurities, whether they are incorporated into the interstitial or Hg
site, we find the interstitial mediated mechanism to be the dominant one. Our calculated barrier of 0.35 eV for Au interstitials
is also in good agreement with the experimental estimate of 0.45 eV. 相似文献
12.
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
13.
Youn Tae Kim Chi Hoon Jun Jong-Tae Baek Hyung Joun Yoo Sang-Koo Chung 《Journal of Electronic Materials》1995,24(10):1413-1417
In this study, we have investigated sensitivities of the ion implanted silicon wafers processed by rapid thermal annealing
(RTA), which can reveal the variation of sheet resistance as a function of annealing temperature as well as implantation parameters.
All the wafers were sequentially implanted by the arsenic or phosphorous implantations at 40, 80, and 100 keV with the dose
level of 1014 to 2 × 1016 ions/cm2. Rapid thermal annealing was carried out for 10 s by the infrared irradiation at a temperature between 850 and 1150°C in
the nitrogen ambient. The activated wafer was characterized by the measurements of the sheet resistance and its uniformity
mapping. The values of sensitivities are determined from the curve fitting of the experimental data to the fitting equation
of correlation between the sheet resistance and process variables. From the sensitivity values and the deviation of sheet
resistance, the optimum process conditions minimizing the effects of straggle in process parameters are obtained. As a result,
a strong dependence of the sensitivity on the process variables, especially annealing temperatures and dose levels is also
found. From the sensitivity analysis of the 10 s RTA process, the optimum values for the implant dose and annealing temperature
are found to be in the range of 1016 ions/cm2 and 1050-1100°C, respectively. The sensitivity analysis of sheet resistance will provide valuable data for accurate activation
process, offering a guideline for dose monitoring and calibration of ion implantation process. 相似文献
14.
M. E. Twigg R. E. Stahlbush K. G. Irvine J. J. Sumakeris T. P. Chow P. A. Lossee L. Zhu 《Journal of Electronic Materials》2005,34(4):351-356
Using plan-view transmission electron microscopy (PVTEM), we have identified stacking faults (SFs) and planar defects in 4H-SiC
PiN diodes subjected to electrical bias. Our observations suggest that not all planar defects seen in the PiN diodes are SFs.
By performing diffraction-contrast imaging experiments using TEM, we can distinguish SFs from other planar defects. In addition,
high-resolution TEM (HRTEM) imaging and analytical TEM have revealed that some planar defects consist of a 3-nm-wide SiC amorphous
layer. Many of these planar defects are orientated parallel to {1
00} planes, whereas others are roughly parallel to the (0001) plane. The appearance of these planar defects suggests that
they are grain boundaries. 相似文献
15.
J. C. Molstad J. D. Benson J. K. Markunas J. B. Varesi P. R. Boyd J. H. Dinan 《Journal of Electronic Materials》2005,34(9):1242-1248
(211) oriented silicon substrates were patterned and etched to give mesas of various sizes and shapes. Cadmium telluride epitaxial
layers were deposited on the patterned substrates by molecular beam epitaxy (MBE). Dislocation termini in the epilayer were
found to be concentrated in the trenches that formed the mesa boundaries. Mesa sizes up to 17 μm were found to be nearly free
of threading dislocation termini. Threading dislocation termini are observed to congregate in lines parallel to the 〈321〉
crystallographic directions. Evidence of subsurface, horizontal dislocations running through the mesa is given. 相似文献
16.
Changzhen Wang Steve Tobin Themis Parodos David J. Smith 《Journal of Electronic Materials》2006,35(6):1192-1196
The microstructure of p-n device structures grown by liquid-phase epitaxy (LPE) on CdZnTe substrates has been evaluated using
transmission electron microscopy (TEM). The devices consisted of thick (∼21-μm) n-type layers and thin (∼1.6-μm) p-type layers,
with final CdTe (∼0.5 μm) passivation layers. Initial observations revealed small defects, both within the n-type layer (doped
with 8×1014/cm3 of In) and also within the p-type layer but at a much reduced level. These defects were not visible, however, in cross-sectional
samples prepared by ion milling with the sample held at liquid nitrogen temperature. Only isolated growth defects were observed
in samples having low indium doping levels (2×1014/cm3). The CdTe passivation layers were generally columnar and polycrystalline, and interfaces with the p-type HgCdTe layers were
uneven. No obvious structural changes were apparent in the region of the CdTe/HgCdTe interfaces as a result of annealing at
250°C. 相似文献
17.
J. Petruzzello J. Gaines P. Van Der Sluis D. Olego T. Marshall C. Ponzoni 《Journal of Electronic Materials》1993,22(5):453-456
We have used transmission electron microscopy (TEM) and high-resolution x-ray diffraction (HRXRD) techniques to investigate
the structural properties of ZnSe doped with nitrogen, in the concentration range of 1 × 1018 to 2 × 1019cm−3. The nitrogen-doped layers contain substantial residual compressive strain at layer thicknesses where undoped ZnSe would
be completely relaxed. The residual strain is clearly observed both in the inequality of the lattice constants (measured by
HRXRD) parallel and perpendicular to the growth direction, and in the reduction of the misfit dislocation density (measured
by TEM) relative to undoped ZnSe. In addition to the reduction in dislocation density, the misfit dislocations form a regular
rectangular grid, rather than the irregular array seen in undoped ZnSe. The effective relaxed ZnSe lattice constant, as measured
by x-ray diffraction, decreases as the nitrogen concentration increases. For the highest nitrogen concentration, this reduction
in lattice constant, however, is greater than can be explained by the shorter Zn-N bond distance of theoretical predictions. 相似文献
18.
Jung-Ja Yang Rafal Spirydon Tae-Yeon Seong S. H. Lee G. B. Stringfellow 《Journal of Electronic Materials》1998,27(10):1117-1123
Transmission electron diffraction (TED) and transmission electron microscope (TEM) studies have been made of organometallic
vapor phase epitaxial GaxIn1−xP layers (x ≈ 0.5) grown at temperatures in the range 570–690°C to investigate ordering and ordered domain structures. TED
and TEM examination shows that the size and morphology of ordered domains depend on the growth temperature. The ordered domains
change from a fine rod-like shape to a plate-like shape as the growth temperature increases. The domains are of width 0.6∼2
nm and of length 1∼10 nm. Characteristic diffuse features observed in TED patterns are found to depend on the growth temperature.
Extensive computer simulations show a direct correlation between the ordered domain structures and such diffuse features.
A possible model is suggested to describe the temperature dependence of the ordered domain structure. 相似文献
19.
R. H. Sewell C. A. Musca J. M. Dell L. Faraone B. F. Usher T. Dieing 《Journal of Electronic Materials》2005,34(6):795-803
Lattice mismatch between substrates and epitaxial layers of different molefractions can create a variety of distortions and
defects in Hg(1−x)Cd(x)Te epilayers, thus degrading the performance of infrared detectors fabricated from this material. X-ray diffraction is a sensitive
nondestructive technique, which allows in-depth characterization of the crystal lattice prior to detector fabrication. We
present results of triple-axis diffractometry performed on single- and double-layer HgCdTe films grown on (211)B CdZnTe substrates
by molecular beam epitaxy (MBE). In this study, both the ω and 2θ diffraction angles have been recorded absolutely so that
the diffraction peaks in the RSMs can be positioned directly in reciprocal space, without requiring reference to a substrate
peak. The positions of both surface-symmetric and asymmetric diffraction peaks have been used to extract lattice spacings
parallel and perpendicular to the (211) growth direction. The relaxed lattice parameter of each epilayer has been calculated
assuming that the layers are elastically strained. The low symmetry of the (211) growth direction, coupled with the anisotropic
elasticity of zinc-blende semiconductors, results in monoclinic distortion of the lattice, as observed in these samples. In
double-layer samples, the mosaicity of both layers is greater than that observed in single epilayers. Layers subjected to
a Hg-saturated anneal show greater lattice distortion than as-grown samples. 相似文献
20.
Yusuf Atici 《Journal of Electronic Materials》2005,34(5):612-616
Interfacial defects due to a mismatch of 1.378% between substrate and epilayer were examined in a Si0.67Ge0.33/Si(001) superlattice by transmission electron microscopy (TEM). Plan-view specimens from the superlattice were prepared to
investigate the defects in the structure. It was observed that 60°C-type misfit dislocations associate with point contrast
on and at their ends. This point contrast was found to represent threading dislocations by using tilt experiments in the microscope.
Consequently, stereo electron microscopy was used to examine the threading dislocations. It was discovered that the threading
dislocations are not on the {111} slip planes but can be almost parallel to the [001] zone axis. 相似文献