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1.
Ruth Zhang Raymond Tsui Kumar Shiralagi John Tresek 《Journal of Electronic Materials》1998,27(5):446-450
We have studied the selective area epitaxy of GaAs by chemical beam epitaxy, using tri-isopropylgallium as the Ga source.
The results show that GaAs can be selectively grown at a rate of up to ∼0.36 μm/h on patterned GaAs substrates at temperatures
as low as 380°C. A low selective growth temperature allows us to utilize deep-ultraviolet radiation to modify the GaAs surface
oxides for use as the masking material. We found that excess AsH3 over-pressure degrades the selectivity significantly, and the maximum selective growth thickness is limited by a critical
total adatom coverage on the mask. In addition, the low selective growth temperature does not result in a very high C background
concentration. Initial Hall measurements indicate that unintentional C doping levels are at least two orders of magnitude
lower than those in GaAs layers grown under comparable conditions using trimethylgallium. 相似文献
2.
Y. Luo L. Zeng W. Lin B. Yang M. C. Tamargo Y. M. Strzhemechny S. A. Schwarz 《Journal of Electronic Materials》2000,29(5):598-602
A concept for in situ device processing has been demonstrated by the fabrication of Au/CdTe device like structures using shadow
mask selective area epitaxy (SAE) and in situ metallization. Patterned CdTe epilayers were grown in the molecular beam epitaxy
(MBE) chamber using shadow mask SAE (in situ patterning) and then directly transferred within ultrahigh vacuum (UHV) into
a metal evaporation chamber for patterned Au deposition (in situ metallization). Excellent pattern definitions of both the
CdTe and Au layers were obtained. Good metal adhesion properties and low levels of contamination at the metal-semiconductor
interface were observed. A specially designed mask fixture that allows the mask to be placed and removed within the UHV chamber
was implemented to perform this work. 相似文献
3.
N. K. Dhar C. E. C. Wood P. R. Boyd H. K. Pollehn M. Martinka J. D. Benson J. H. Dinan 《Journal of Electronic Materials》1995,24(9):1041-1046
Amorphous layers of CdTe deposited on Cd or Zn terminated GaAs {001} surfaces can be recrystallized above ∼200°C. Subsequent
molecular beam epitaxy of CdTe proceeds in a two-dimensional mode and leads to layers which are specular and single domain
{0011}. Threading dislocation density in these layers was 1–2 x 105 cm−2. Values of full width at half maximum for x-ray rocking curves were as low as 80 arc-s. 相似文献
4.
L. A. Almeida Y. P. Chen J. P. Faurie S. Sivananthan David J. Smith S. -C. Y. Tsen 《Journal of Electronic Materials》1996,25(8):1402-1405
We have systematically studied the growth of CdTe (lll)B on Si(001)with different atomic step structures, defined uniquely
by miscut tilt angle and direction. X-ray double crystal rocking curve (DCRC) analysis has been used to evaluate the crystalline
quality and twin content of the films. High-resolution electron microscopy has been used to examine the CdTe(lll)B/Si(001)
interface and to follow the microstructural evolution as a function of distance from the interface. Our results show that
the formation of double domains and twins is very sensitive to the tilt parameters. When growth conditions are optimized,
twins are not observed at distances greater than about 2.5 microns from the substrate surface. The best quality films exhibit
a DCRC FWHM of 60 arc sec, for a film thickness of 17 μm, the lowest value ever reported for heteroepitaxial growth of CdTe
on Si or GaAs. In efforts to improve the nucleation process, precursors such as Te and As have been used, and we have shown
that they improve the stability of the heterointerface. 相似文献
5.
V. K. Gupta K. L. Averett M. W. Koch B. L. McIntyre G. W. Wicks 《Journal of Electronic Materials》2000,29(3):322-324
Ammonia cracking efficiencies on various surfaces were examined. The following is an ordering of surfaces according to their
ammonia cracking efficiencies: GaN (highest), Si3N4, SiO2 (lowest). Selective area growth of GaN was performed over SiO2 masks deposited on GaN previously grown on sapphire substrates using ammonia-based molecular beam epitaxy. GaN growth on
patterned SiO2/GaN is very selective at a growth temperature of 800°C. Good quality growth occurs in the window region with no deposits
on the mask surface when growth is performed at 800°C, whereas some deposits on the SiO2 masks accumulate when growth is performed at 700°C. The ratio of lateral growth rate to vertical growth rate is ≤1. 相似文献
6.
M. S. Han T. W. Kang J. H. Leem B. K. Song Y. B. Hou W. H. Baek M. H. Lee J. H. Bahng K. J. Kim J. M. Kim H. K. Kim T. W. Kim 《Journal of Electronic Materials》1997,26(6):507-510
Spectroscopic ellipsometry and photoreflectance measurements on CdTe/GaAs strained heterostructures grown by moleculclr beam
epitaxy were carried out to investigate the effect of the strain and the dependence of the lattice parameter on the CdTe epitaxial
layer thicknesses. Compressive strains exist in CdTe layers thinner than 2 μm. As the strain increases, the value of the critical-point
energy shift increases linearly. These results indicate that the strains in the CdTe layers grown on GaAs substrates are strongly
dependent on the CdTe layer thickness.
Author to whom all correspondence should be addressed. 相似文献
7.
M. S. Han S. R. Hahn H. C. Kwon Y. Bin T. W. Kang J. H. Leem Y. B. Hou H. C. Jeon J. K. Hyun Y. T. Jeoung H. K. Kim J. M. Kim T. W. Kim 《Journal of Electronic Materials》1998,27(6):680-683
Double-crystal x-ray rocking curve (DCRC) and secondary-ion mass-spectroscopy (SIMS) measurements have been performed to investigate the effect of rapid thermal annealing on the interdiffusion behavior of Hg in HgTe/CdTe superlattices grown on Cd0.96Zn0.04Te (211)B substrates by molecular beam epitaxy. The sharp satellite peaks of the DCRC measurements on a 100-period HgTe/CdTe (100Å/100Å) superlattice show a periodic arrangement of the superlattice with high-quality interfaces. The negative direction of the entropy change obtained from the diffusion coefficients as a function of the reciprocal of the temperature after RTA indicates that the Hg diffusion for the annealed HgTe/CdTe superlattice is caused by an interstitial mechanism. The Cd and the Hg concentration profiles near the annealed HgTe/CdTe superlattice interfaces, as measured by SIMS, show a nonlinear behavior for Hg, originating from the interstitial diffusion mechanism of the Hg composition. These results indicate that a nonlinear interdiffusion behavior is dominant for HgTe/CdTe superlattices annealed at 190°C and that the rectangular shape of HgTe/CdTe superlattices may change to a parabolic shape because of the intermixing of Hg and Cd due to the thermal treatment. 相似文献
8.
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
9.
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
10.
N. C. Giles Jaesun Lee T. H. Myers Zhonghai Yu B. K. Wagner R. G. Benz C. J. Summers 《Journal of Electronic Materials》1995,24(5):691-696
A comprehensive study of the properties of undoped and iodine-doped CdTe structures by photoluminescence (PL) and photoreflectance
(PR) is reported. Undoped bulk CdTe and iodine-doped CdTe layers grown by metalorganic molecular beam epitaxy on (lOO)-oriented
CdTe and (211)B-oriented GaAs substrates with electron concentrations ranging from 1014 to mid-1018 cm-3 were included in this study. Lineshape modeling of 80KPL and PR spectra indicated the presence of both free exciton and donor-hole
transitions at the higher doping levels. Strong PL and PR signals were also observed at room temperature. If only a single
transition is considered for the analysis of the 300K spectra, the PL emission peak and the PR transition energy both exhibit
a strong dependence on electron concentration for doped layers. However, lineshape modeling of the room-temperature spectra
indicated the presence of multiple transitions consisting of free exciton and direct band-to-band transitions. The use of
two transitions resulted in a constant value of bandgap over the entire range of conductivities studied. A strong correlation
remained between the broadening of the PR and PL spectra and excess carrier concentration ND-NA. In addition, the E1 transition energy measured by PR was found to vary dramatically with growth conditions. 相似文献
11.
A. Parikh S.D. Pearson B.K. Wagner C.J. Summers 《Journal of Electronic Materials》1997,26(9):1065-1069
A study is reported of the dynamics of dopant incorporation in iodine doped CdTe. Using a mathematical formulation, the iodine
doping profiles in CdTe and HgCdTe have been fitted to experiment to obtain material parameters such as the bulk and surface
diffusion and the segregation energy. Dopant profile fitting showed that iodine diffusion was insignificant and gave an iodine
segregation energy of 0.6 eV and a surface diffusivity enhancement factor of 300 at a growth temperature of 230°C. The model
was used to determine the effect of the growth rate and temperature for particular growth conditions. 相似文献
12.
Zhonghai Yu S. L. Buczkowski M. C. Petcu N. C. Giles T. H. Myers M. Richards-Babb 《Journal of Electronic Materials》1996,25(8):1247-1253
Nitrogen doping in CdTe epilayers grown by photo-assisted molecular beam epitaxy was demonstrated using an rf plasma source.
The effect of the presence of atomic hydrogen during growth of undoped and nitrogen-doped CdTe was investigated. The layers
were characterized using photoluminescence spectros-copy (PL), Hall effect, secondary ion mass spectroscopy (SIMS), Fourier
transform infrared spectroscopy, and atomic force microscopy. PL confirmed the incorporation of nitrogen as acceptors. While
p-type carrier concentrations greater than 1018 cm−3 were easily obtained, SIMS measurements indicated that nitrogen was concentrated near the undoped-doped and epilayer-substrate
interfaces which complicates interpretation of activation efficiency. Hydrogen incorporation was found to be enhanced by the
presence of nitrogen. Infrared absorption measurements strongly suggested the formation of N-H complexes. Hall measurements
indicated that complexes are formed which are donor-like in nature. The presence of atomic hydrogen during growth radically
changed the low temperature photoluminescence in both undoped and nitrogen-doped layers. Exciton-related luminescence was
quenched at low temperature. Nitrogenrelated donor-acceptor pair luminescence was also absent from the N-doped hydrogenated
layers, consistent with complex formation. Copper (a cation-site acceptor) donor-acceptor pair luminescence appeared to be
enhanced by hydrogenation. 相似文献
13.
In this paper, we report on the atomic layer epitaxy (ALE) of CdTe on GaAs and Si by the organometallic vapor phase epitaxial
process at atmospheric pressure. Self-limiting growth at one monolayer was obtained over the temperature range from 250°C
to 320°C, under a wide range of reactant pressure conditions. A study of growth mechanism indicates that DMCd decomposes into
Cd on the surface and the Te precursors react catalytically on the Cd covered surface. We have used this ALE grown layer to
improve the crystal quality and the morphology of conventionally grown CdTe on GaAs. Improvement in the crystal quality was
also observed when ALE CdTe nucleation was carried out on Si pretreated with DETe at 420°C. Atomic layer epitaxy grown ZnTe
was used to obtain (100) oriented CdTe on (100) silicon. 相似文献
14.
X.J. Wang C. Fulk F.H. Zhao D.H. Li S. Mukherjee Y. Chang R. Sporken R. Klie Z. Shi C.H. Grein S. Sivananthan 《Journal of Electronic Materials》2008,37(9):1200-1204
Narrow-bandgap PbSnSe has received much attention as a promising alternative material for mid- and long-wavelength high performance
of infrared detection at relatively high operating temperatures owing to the weak composition dependence of its bandgap, which
can intrinsically result in better uniformity. Additionally, it possesses a high dielectric constant that is anticipated to
be much more tolerant to defects. In addition, its growth by molecular beam epitaxy (MBE) can be easily accomplished in comparison
with HgCdTe and many III–V quantum well and superlattice materials. However, overcoming the high lattice and thermal mismatches
between PbSnSe and CdTe/Si substrates and improving the crystalline quality of PbSnSe grown on CdTe/Si substrates are challenges
that require further study. Additionally, interdiffusion between CdTe and PbSnSe can take place and lead to nonuniform distributions
of elements in PbSnSe. Epitaxial crystal PbSnSe alloy films were grown by MBE and were investigated by scanning and high-resolution
transmission electron microscopy (STEM/HRTEM). Etch pit density (EPD) measurements were done to determine the density of threading
defects in the films. EPD measurements on PbSnSe surfaces gave values in the mid-106 cm−2 range. The dislocations exposed as etch pits were found to accumulate and form small-angle grain boundaries lined up along
the () direction, which is the intersection line between (100) and (211) growth planes. 相似文献
15.
A. Gurary G. S. Tompa S. Liang R. A. Stall Y. Lu C. -Y. Hwang W. E. Mayo 《Journal of Electronic Materials》1993,22(5):457-461
Molecular beam epitaxy (MBE) is an advanced deposition technique known to produce high quality semiconductor films and structures.
While great progress has been achieved in recent years, MBE still suffers from problems with elemental flux control which
include: flux instabilities, long respoNSe times, significant transients, and difficulty of scaling to large area depositions. The elemental vapor transport epitaxy
(EVTE) technique was formulated to resolve several problems typically accompanying conventional MBE. In EVTE, the vapor sources
feed through regulating valves into a common flux distribution manifold that is located below the inverted wafer. We previously
reported the EVTE growth of GaAs without gallium source related oval defects. In this paper, we report on EVTE deposition
of the ZnSe, ZnTe, CdSe, CdTe, and ZnTe-ZnSe on GaAs (100) substrates. We have achieved selenium elemental flux control with
respoNSe times less than one second and deposited films thickness uniformity ± 1.8% over a 2.0″substrate. Elemental vapor transport
epitaxy grown materials show good surface morphology and stoichiometry, sharp interface, and low outdiffusion from the substrate.
X-ray analysis showed crystallinity (FWHM = 95 arcsec) of the ZnSe films. 相似文献
16.
N-type ZnSe with electron concentration up to 3 × 1020 cm−3 and low resistivity down to 1 × 10−4 ohm-cm, has been grown using a selective doping technique with chlorine during molecular beam epitaxy. The photoluminescence
evaluation shows that the selectively doped ZnSe layers are superior to uniformly doped ones, especially for the case of high-concentration
chlorine doping. The in-depth profile of chlorine concentration in a selectively doped sample was measured with secondary-ion
mass spectroscopy (SIMS). The SIMS analysis shows only slight diffusion of the incorporated chlorine atoms even in highly
doped samples. 相似文献
17.
Using the molecular beam epitaxial (MBE) technique, CdTe and Hg1-xCdxTe have been grown on Cr-doped GaAs (100) sub-strates. A single effusion cell charged with polycrystal-line CdTe is used for the growth of CdTe films. The CdTe films grown at 200 °C with a growth rate of ~ 2 μm/hr show both streaked and “Kikuchi” patterns, indicating single crystalline CdTe films are smoothly grown on the GaAs sub-strates. A sharp emission peak is observed at near band-edge (7865 Å, 1.577 eV) in the photoluminescence spectrum at 77 K. For the growth of Hg1-xCdxTe films, separate sources of HgTe, Cd and Te are used. Hg0.6Cd0.4Te films are grown at 50 °C with a growth rate of 1.7 μm/hr. The surfaces are mirror-smooth and the interfaces between the films and the substrates are very flat and smooth. As-grown Hg0.6Cd0.4Te films are p-type and converted into n-type by annealing in Hg pressure. Carrier concentration and Hall mobility of an annealed Hg0.6Cd0.4Te film are 1 × 1017 cm?3 and 1000 cm2/V-sec at 77 K, respectively. 相似文献
18.
Y. P. Chen J. P. Faurie S. Sivananthan G. C. Hua N. Otsuka 《Journal of Electronic Materials》1995,24(5):475-481
CdTe(lll)B layers have been grown on misoriented Si(001). Twin formation inside CdTe(lll)B layer is very sensitive to the
substrate tilt direction. When Si(001) is tilted toward [110] or [100], a fully twinned layer is obtained. When Si(001) is
tilted toward a direction significantly away from [110], a twin-free layer is obtained. Microtwins inside the CdTe(111)B layers
are overwhelmingly dominated by the lamellar twins. CdTe(111)B layers always start with heavily lamellar twinning. For twin-free
layers, the lamellar twins are gradually suppressed and give way to twin-free CdTe(111)B layer. The major driving forces for
suppressing the lamellar twinning are the preferential orientation of CdTe[11-2] along Si[1-10] and lattice relaxation. Such
preferential orientation is found to exist for the CdTe(111)B layers grown on Si(001) tilted toward a direction between [110]
and [100]. 相似文献
19.
R. Sporken D. Grajewski Y. Xin F. Wiame G. Brill P. Boieriu A. Prociuk S. Rujirawat N. K. Dhar S. Sivananthan 《Journal of Electronic Materials》2000,29(6):760-764
CdTe
B was grown on As-terminated Si(111) by molecular beam epitaxy (MBE). Nucleation and interface properties were studied by
photoelectron spectroscopy, scanning tunneling microscopy, electron diffraction, and energy-dispersive spectroscopy of x-rays.
Selective growth on Si(111) was investigated either by using SiO2 as a mask, or by growing on a patterned CdTe seed layer. The highest temperature where CdTe nucleates on As-terminated Si(111)
surfaces is typically in the range of 220–250°C. On a SiO2 mask, CdTe nucleates at the same temperatures, leading to polycrystalline growth. However, homoepitaxy of CdTe is possible
around 300°C. Hence, CdTe can be grown selectively on a patterned CdTe seed layer on Si(111). This is confirmed by scanning
electron microscopy and scanning Auger microscopy. 相似文献
20.
Complete selective area growth of InP could be achieved at standard molecular beam epitaxial growth temperatures by using
solid source epitaxy with an additional hydrogen rf-plasma (27 MHz) excited in the reaction chamber. By optimization of the
process parameters such as substrate temperature, plasma power, and phosphorus overpressure, mirror-like InP-layers with geometry
independent growth rates were grown on SiN-patterned InP substrates without polycrystalline growth on the mask. Since selective
growth is also possible in an argon plasma, we conclude that a physical desorption process is the mechanism for selective
area growth in this plasma assisted epitaxy method. Furthermore, the selectivity can be controlled by a dc-bias of the substrate,
which influences the mean energy of the impinging ions, thereby changing the desorption rate of atoms from the mask. 相似文献