共查询到20条相似文献,搜索用时 15 毫秒
1.
H. Q. Hou W. G. Breiland B. E. Hammons R. M. Biefeld K. C. Baucom R. A. Stall 《Journal of Electronic Materials》1997,26(10):1178-1183
We present a comprehensive study on the growth of AlGaAs by using an alternative Al precursor, dimethylethylamine alane (DMEAA),
and a Ga coprecursor, either triethylgallium (TEG) or trimethylgallium (TMG). The growth rate of AlAs determined by using
in situ reflectometry was studied as a function of the growth temperature, V/III ratio, growth pressure, and rotation speed of the
substrate. The presence of gas phase reactions of DMEAA with arsine and TEG was indicated, and their reduction was achieved
at a lower growth pressure, lower V/III ratio, or a lower growth temperature. Negligible pre-reaction of DMEAA with TMG was
observed. Excellent material uniformity of AlGaAs was achieved on a 2″ diameter wafer. Secondary ion mass spectroscopy measurements
revealed extremely low C and O contents in the AlAs layer grown by DMEAA. Photoluminescence measurements suggested the presence
of some non-radiative defects in the as-grown DMEAA AlGaAs layers. 相似文献
2.
Akihiko Ishibashi Hidemi Takeishi Masaya Mannoh Yasufumi Yabuuchi Yuzaburoh Ban 《Journal of Electronic Materials》1996,25(5):799-803
Residual impurities in GaN films on sapphire (A12O3) substrates grown by two-step metalorganic vapor phase epitaxy (MOVPE) have been investigated. We have mainly investigated
the incorporation of carbon into the GaN films with GaN buffer layers on A12O3 during MOVPE growth, comparing trimethygallium (TMGa) and triethygallium (TEGa) as the typical gallium precursors. The films
were characterized by secondary ion mass spectroscopy analysis, photolu-minescence, and Hall measurements. The carbon, hydrogen,
and oxygen concentrations increase with decreasing growth temperature in using TMGa. Especially the carbon concentration increases
with decreasing a V/III ratio, for both TMGa and TEGa. There is about two times more carbon in the GaN films grown using TEGa
than those using TMGa. The carbon from TMGa mainly enhances the D-A pair emission (∼378 nm), which shows the carbon makes
an acceptor level at nitrogen sites in GaN. On the other hand, the carbon from TEGa enhances a deep emission (∼550 nm), which
shows the carbon makes not only an acceptor level but deep levels at interstitial sites in GaN. The carbon impurities originate
from methyl radicals for TMGa, or ethyl radicals for TEGa. It is supposed that, in the case of TEGa, the carbon impurities
are not always located at nitrogen sites, but are also located at interstitial sites because of the C-C bonding in ethyl radicals. 相似文献
3.
Dong H. K. Li N. Y. Tu C. W. Geva M. Mitchel W. C. 《Journal of Electronic Materials》1995,24(2):69-74
The growth of GaAs by chemical beam epitaxy using triethylgallium and trisdimethylaminoarsenic has been studied. Reflection
high-energy electron diffraction (RHEED) measurements were used to investigate the growth behavior of GaAs over a wide temperature
range of 300–550°C. Both group III- and group Vinduced RHEED intensity oscillations were observed, and actual V/III incorporation
ratios on the substrate surface were established. Thick GaAs epitaxial layers (2–3 μm) were grown at different substrate temperatures
and V/III ratios, and were characterized by the standard van der Pauw-Hall effect measurement and secondary ion mass spectroscopy
analysis. The samples grown at substrate temperatures above 490°C showed n-type conduction, while those grown at substrate
temperatures below 480°C showed p-type conduction. At a substrate temperature between 490 and 510°C and a V/III ratio of about
1.6, the unintentional doping concentration is n ∼2 × 1015 cm−3 with an electron mobility of 5700 cm2/V·s at 300K and 40000 cm2/V·s at 77K. 相似文献
4.
S. M. Hubbard D. Pavlidis V. Valiaev A. Eisenbach 《Journal of Electronic Materials》2002,31(5):395-401
Low-pressure, metal-organic vapor-phase epitaxy (MOVPE) was used to grow AlN/GaN metal-insulator-semiconductor (MIS) heterostructures
with AlN thickness between 3 nm and 30 nm. The Hall mobility was found to decrease with increasing AlN thickness, with optimal
mobility measured at 5-nm AlN. By decreasing the ammonia flow during AlN growth (lower V/III ratio), surface and interface
quality were greatly improved with a corresponding improvement in electrical properties. For the optimal V/III ratio, room-temperature
(RT) mobility and sheet charge were 891 cm2/Vs and 2.15×1013 cm−2, respectively. The best RT mobility, for both optimal V/III and thickness, was 1015 cm2/Vs with a sheet charge of 1.1×1013 cm−2. 相似文献
5.
We report an OMVPE growth process for InP using trimethylindium (TMI) and tertiarybutylphosphine (TBP), a V/III ratio of 15,
and a TBP partial pressure of 0.5 Torr. Growth is initiated with a 0.1 μm buffer layer employing a ramped TBP flow. Results
are presented for InP grown with two different samples of both TMI and TBP and compared to previous experimental results and
theoretical predictions. Good surface morphology is obtained from 540 to 600° C. The net carrier concentrations, Nd-Na, decrease with increasing growth temperature—but never fall below 1.3 × 1016 cm-3. Mobilities of 3990 and 11200 cm2/V.sec are observed at 300 and 77 K, respectively. At 77 K, we infer a compensation ratio of ∼0.4, independent of Nd-Na. Photoluminescence measurements at 6 K show intense near bandgap emission with a full width half maximum proportional to
Nd-Na. Weak emission is also observed from carbon acceptors, independent of growth temperature. Secondary ion mass spectroscopy
measurements are performed on an InP wafer grown with four different temperatures. The observed sulfur concentration drops
from 1 × 1018 to 6 × 1016 cm-3 with increasing growth temperature. This confirms that sulfur is an important residual impurity in TBP. The observed carbon
concentration is 4–6 × 1016 cm-3, regardless of growth temperature. 相似文献
6.
Hiroshi Watanabe Mitsutake Motozawa Ken Suto Jun-Ichi Nishizawa 《Journal of Electronic Materials》1998,27(8):979-984
Photocapacitance (PHCAP) and photoluminescence (PL) measurements were applied to unintentionally doped p-type Al0.38Ga0.62As grown by liquid phase epitaxy using the temperature difference method under controlled vapor pressure. PHCAP spectra revealed
three dominant deep levels at Ev+0.9, Ev + 1.45, and Ev+1.96 eV, and a deep level at Ev+0.9−1.5 eV which was not neutralized by forward bias injection. These level densities increase with increasing arsenic vapor
pressure and net shallow acceptor density. Furthermore, PL spectra reveal a deep level at 1.6–1.7 eV. The PL intensity of
this deep level increases with increasing arsenic vapor pressure. These deep levels are thought to be associated with excess
As. 相似文献
7.
GaN epitaxial layers were grown at high growth rates by increasing the input trimethylgallium (TMG) flow rate while keeping
the NH3 flow rate constant in metalorganic chemical vapor deposition. The electrical and optical properties of the grown layers have
been investigated. With the increasing TMG flow rate, the electron concentration tends to decrease gradually and the Hall
mobility decreases significantly. Considering the temperature dependence of the Hall mobility and the correlation between
the Hall mobility and the electron concentration, it has been indicated that the more acceptors are incorporated and consequently
the compensation ratio becomes higher with increasing the TMG flow rate. Photoluminescence measurements have revealed that
the intensity ratio of the bound exciton emission to the 2.2 eV band emission, which is assumed to correlate to carbon or
Ga vacancies, was decreased with increasing the TMG flow rate. It might be reasonable to take a lot of acceptor incorporation
to explain the degradation of the electrical and optical properties in the samples grown at high growth rates by increasing
the TMG flow rate. 相似文献
8.
CVD growth conditions, particularly growth temperature and partial pressures of the reactant gases, strongly affect the growth
characteristics and properties of GaAs0.6P0.4 epitaxial layers grown on GaAs substrates. For LED’s the most important properties of the material are B/J (brightness per
unit current density) and surface morphology. This paper presents the results of a systematic study of the effect of temperature
and reactant gas partial pressure (at a fixed III/V ratio) on B/J, surface morphology, growth rate, impurity doping and layer
composition. Growth conditions which yield the optimum properties for LED’s are determined. The results are interpreted on
the basis of kinetic and thermodynamic mechanisms controlling the growth process under various growth conditions. At constant
temperature and constant III/V ratio, increasing the partial pressures causes the growth process to change from mass transport
limited, where the growth rate increases with increasing partial pressures, to kinetically limited, where the growth rate
is independent of partial pressures. Good morphology layers are obtained over a range of partial pressures around the transition
from mass transport limited to kinetically limited growth. The B/J peaks at a value of partial pressure in the kinetically
limited regime at which good morphology layers are obtained. Although B/J increases with increasing growth rate in the mass
transport regime, the maximum B/J occurs in the region where growth rate is independent of partial pressures so that growth
rate alone is not sufficient to determine B/J. In contrast to the “parabolic≓ dependence of growth rate on growth temperature,
caused by the transition from the mass transport regime to the kinetic regime, the relative incorporation of As, P, and Te
varies with temperature in the manner predicted from thermodynamics in both regimes. This behavior is consistent with the
growth rate in the kinetic regime being limited by the desorption of chlorine atoms from the growth surface, with the reaction
of As, P, and Te with the Ga proceeding thermodynamically at all temperatures. 相似文献
9.
Zinc-blende GaN films were grown on GaAs (100) substrates by low-pressure metalorganic vapor phase epitaxy using trimethylgallium
or triethylgallium and NH3. Films grown at lower temperatures contained considerable amounts of carbon, but the carbon concentration was reduced in
high temperature growth. When the film was grown at 950°C using triethylgallium and NH3, its carbon concentration was on the order of 1017 cm−3. The crystalline and optical quality of zinc-blende GaN crystal also improved with high-temperature growth at a low V/III
ratio using a thin buffer layer. The films exhibited only one sharp photoluminescence peak at 3.20 eV with a full width at
half maximum as low as 70 meV at room temperature. 相似文献
10.
Sun-Hong Park Chul-Hwan Choi Kyoung-Bo Kim Seon-Hyo Kim 《Journal of Electronic Materials》2003,32(11):1148-1154
High-quality ZnO thin films were prepared by metal-organic chemical vapor deposition (MOCVD) on a sapphire (a-Al2O3) substrate. The synthesis of ZnO films was performed over a substrate temperature of 400–700°C and at chamber pressures of
0.1–10 torr. The structural and optical properties of ZnO films were investigated in terms of deposition conditions, such
as substrate temperature, working pressure, and the ratio of Zn precursor (Diethylzinc (DEZn)) to oxygen. The ZnO films, preferentially
oriented to 34.42° diffraction because of the (002) plane, were obtained under processing conditions of 700°C and 3 torr.
This film shows a full-width at half-maximum (FWHM) of 0.4–0.6°. The results of photoluminescence (PL) spectroscopy also show
a strong near band-edge emission at 3.36 eV at 10 K as well as a very weak emission at deep levels around 2.5 eV at room temperature.
In addition, we are interested in the introduction of ZnO buffer-layer growth by the sputtering process to reduce lattice
mismatch stress. This paper addresses how to advance the crystalline and optical properties of film. The ZnO film grown with
the aid of a buffer layer shows a FWHM of 0.06–0.1° in the x-ray diffraction (XRD) pattern. This result indicates that crystalline
properties were highly improved by the ZnO buffer layers. The PL spectroscopy data of ZnO film also shows a strong near band-edge
emission and very weak deep-level emission similar to films synthesized without a buffer layer. Accordingly, synthesized ZnO
films with buffer layers indicate fairly good optical properties and low defect density as well as excellent crystallinity. 相似文献
11.
We investigated Schottky barrier diodes of several metals (Ti, Ni, and Au) having different metal work functions to p-type
4H−SiC (0001) using I–V and C–V characteristics. Contacts showed excellent Schottky behavior with stable ideality factors
of 1.07, 1.23, and 1.06 for Ti, Ni, and Au, respectively, in the range of 24°C to 300°C. The measured Schottky barrier height
(SBH) was 1.96, 1.41, and 1.42 eV for Ti, Ni, and Au, respectively, in the same temperature range from I–V characteristics.
Based on our measurements for p-type 4H−SiC, the SBH (φBp) and metal work functions (φm) show a linear relationship of φBp = 4.58 − 0.61φm and φBp = 4.42 − 0.54φm for I–V and C–V characteristics at room temperature, respectively. We observed that the SBH strongly depends on the metal
work function with a slope (S ≡ φBp/φm) of 0.58 even though the Fermi level is partially pinned. We found the sum of the SBH (φBp + φBn = Eg) at room temperature for n-and p-type 4H−SiC to be 3.07 eV, 3.12 eV, and 3.21 eV for Ti, Ni, and Au, respectively, using
I–V and C–V measurements, which are in reasonable accord with the Schottky-Mott limit. 相似文献
12.
B. K. Han L. Li M. J. Kappers R. F. Hicks H. Yoon M. S. Goorsky K. T. Higa 《Journal of Electronic Materials》1998,27(2):81-84
Thin films of InxGa1−xAs (0<x<0.012) on GaAs (001) were grown by metalorganic vapor phase epitaxy using triisopropylindium, triisobutylgallium,
and tertiarybutylarsine. The effect of the process conditions, temperature, and V/III ratio on the film quality was studied
using high resolution x-ray diffraction, scanning tunneling microscopy, and Hall measurements. High quality films were grown
at temperatures as low as 475 °C and at a V/III ratio of 100. However, under these conditions, a change in growth mode from
step flow to two-dimensional nucleation was observed. 相似文献
13.
X. B. Zhang R. D. Heller M. S. Noh R. D. Dupuis G. Walter N. HolonyakJr. 《Journal of Electronic Materials》2003,32(11):1335-1338
We report on the growth of InP self-assembled quantum dots (QDs) on In0.5Al0.5P matrices by metal-organic chemical vapor deposition (MOCVD) on (001) GaAs substrates. The effects of the growth temperature
and V/III-precursor flow ratio on the areal density and the cathodoluminescence (CL) properties of the grown QDs were systematically
studied. We found that, when the growth temperature is ≤630°C, coherent QDs as well as large dislocated InP islands can be
observed on the matrix surface. However, by using a two-step growth method, i.e., by growing the InAlP matrix layer at higher
temperatures and growing InP QDs at lower temperatures, the formation of large dislocated islands can be effectively suppressed.
Moreover, the areal density of the InP QDs is increased as the QD growth temperature is reduced. Furthermore, we found that
the V/III ratio used in growing QDs and in growing the InAlP matrix layers has a quite different effect. In growing QDs, decreasing
the V/III ratio results in an increase in the CL intensity and a decrease in CL line width; while in growing the InAlP matrix
layers, increasing the V/III ratio results in an increase in the CL intensity of the InP QDs. 相似文献
14.
Oxygen has always been considered to be a major contaminant in the organo-metallic vapor phase epitaxy (OMVPE) of Al
x
Ga1−x
As. Oxygen incorporation has been invoked as a contributor to low luminescence efficiency, dopant compensation and degradation
of surface morphology among other deleterious effects. This study presents quantitative measurements of oxygen concentration
in nominally high purity Al
x
Ga1−x
As. The oxygen concentration was measured as a function of alloy composition, growth temperature, andV/III ratio. Quantitative secondary ion mass spectroscopy (SIMS) measurements were used to determine the oxygen content as well
as the carbon concentration in the film. The oxygen concentration increases with decreased growth temperature and V/III ratio
while increasing superlinearly with Al content in the epitaxial layer. 相似文献
15.
C. Pelosi G. Attolini C. Bocchi P. Franzosi C. Frigeri M. Berti A. V. Drigo F. Romanato 《Journal of Electronic Materials》1995,24(11):1723-1730
GaAs epitaxial layers have been grown on (001) 6† off-oriented toward (110) Ge substrates by metalorganic vapor phase epitaxy.
In order to study the influence of V/III ratio on the growth mechanisms and the structural properties of the layers, the input
flow of arsine was changed over a wide range of values, while keeping constant all other experimental settings. Optical microscopy
in the Nomarski contrast mode, x-ray topography and high resolution diffractometry, transmission electron microscopy and Rutherford
backscattering have been used to investigate the epilayers. It has been found that the growth rate increases and the surface
morphology worsens with increasing V/III ratio. The abruptness of the layer-substrate interface has also been found to strongly
depend on the V/III ratio, the best results being obtained under Ga-rich conditions. The main structural defects within the
layers are stacking faults and misfit dislocations. Layers grown under As-rich conditions only contain stacking faults, probably
originated by a growth island coalescence mechanism, whereas layers grown under Ga-rich conditions contain both misfit dislocations
and stacking faults generated by dissociation of threading segments of interfacial dislocations. In spite of the different
defects, the strain relaxation has been found to follow the same trend irrespective of the V/III ratio. Finally, the relaxation
has been found to start at a thickness exceeding the theoretical critical value. 相似文献
16.
Characterization of silicon oxide films grown at room temperature by point-to-plane corona discharge
Oxide films grown on silicon in dry oxygen ambient at room temperature by negative point-to-plane corona discharge are investigated.
A significant oxidation rate is observed at room temperature using this technique. Electrical properties of these room termperature
grown oxides are examined. The capacitance-voltage measurements on the MOS structures fabricated from these oxides indicate
a negative flat-band voltage of −1.5 V. Interface state density distribution in the range of 1010−1013 cm−2(eV)−1 is observed with a value of 2×1010 cm−2(eV)−1 at 0.17 eV above the valence band edge. Electrical conduction through the oxide is greater for negative values of applied
gate bias voltages and the magnitude of conduction through the oxide decreases with decreasing current density during the
corona discharge. Oxides grown at room temperature by this technique may find selective application in low temperature device
processing. 相似文献
17.
Conditions for growth at 550°C of high structural quality GaInAs by LPMOCVD are presented. The sensitivity of compositional
grading to changes in the V/III molar ratio, growth rate and inclusion of InP buffer layers is discussed. Crystalline uniformity
is indicated by double crystal x-ray rocking curves with FWHM (GaInAs) = 0.017°. By careful control of the V/III molar ratio,
epitaxial GaInAs/InP heterostructures with δa/a ≤ 10−4 can be grown. Quantitative data for the TEIn-AsH3 elimination reaction rate is presented. The composition of Ga1−xInxAs which is expected in the presence of this reaction is calculated; evaluation of the corresponding rate constant shows that
the adduct formation reaction proceeds at a modest but detectable rate. The problems associated with the purity of electronic
grade triethylindium (TEIn) are addressed. Impurities in commercial TEIn have been determined by low resolution mass spectroscopy. 相似文献
18.
Nick Julian Phil Mages Chong Zhang Jack Zhang Stephan Kraemer Susanne Stemmer Steven Denbaars Larry Coldren Pierre Petroff John Bowers 《Journal of Electronic Materials》2012,41(5):845-852
The effects of V/III ratio and seed window orientation on the coalescence of epitaxial lateral overgrowth InP over SiO2 using metal organic vapor-phase epitaxy with tertiary butyl phosphine were investigated. Parallel lines having θ = 60° and 30° off [0[`1] \bar{1} 1] were coalesced, and their lateral growth rate variation with V/III was measured. Coalescence of lines separated by narrow
angles in a star-like pattern was also studied. We find the greatest extent of coalescence to occur when the window stripe
is oriented just off of the ⟨010⟩ directions. V/III ratio strongly affects the extent of coalescence, showing an alternating
enhancement or inhibition depending on which side of the ⟨010⟩ direction the stripes are oriented. The variation in quality
of coalesced material between stripes separated by narrow angles is examined with cross-sectional transmission electron microscopy,
illustrating the most problematic growth directions under two V/III ratio conditions. 相似文献
19.
G. B. Stringfellow 《Journal of Electronic Materials》1988,17(4):327-335
A major limitation to the continuing development of organometallic vapor phase epitaxy (OMVPE) for the growth of III/V semiconductor
materials is the hazard posed by the hydride sources, AsH3 and PH3, which are virtually universally used, in high pressure cylinders, as the group V source materials for the growth of the
highest quality materials. The ideal group V source would be a nontoxic liquid with a moderate vapor pressure (50-500 Torr).
To be suitable for OMVPE growth, the molecule must pyrolyze at ordinary growth temperatures, be stable against decomposition
in the bottle at room temperature, and not participate in undesirable parasitic reactions with the group III source molecules.
The new sources have additional constraints related to purity. They must be easily purified without decomposing and produce
no detectable carbon contamination in the resultant epitaxial layers. This set of stringent requirements eliminates most commonly
available non-hydride group V sources. Recent research on newly developed sources has shown considerable promise. The entire
area of group V sources, including the elemental sources, for OMVPE growth of III/V materials will be reviewed. The sources
with no hydrogen atoms attached to the group V atom, the elemental, trimethyl-V, and triethyl-V, sources all appear to give
unacceptably high carbon incorporation. Diethylarsine, which has one H attached to the As, produces high quality GaAs but
has an inconveniently low vapor pressure. Trimethylphosphine and triethylphosphine o not pyrolyze at low enough temperatures
to be useful for conventional OMVPE growth. Tertbutylarsine (TBAs) and tertbutylphosphine (TBP) appear to be promising source
materials. TBP has a very low toxicity, a vapor pressure ideal for OMVPE growth, and the pyrolysis occurs at lower temperatures
than for PH3, allowing the use of low values of V/III ratio for the growth of high quality material. No carbon contamination can be attributed
to the TBP. Control of the As/P ratio in OMVPE grown GaAsP is much improved for TBP as compared with PH3 due to the more rapid pyrolysis. At normal growth temperatures the P distribution coefficient is nearly unity. TBAs has been
less studied, but appears to have similar attributes including a favorable vapor pressure and lower pyrolysis temperature
than AsH3, allowing OMVPE growth of GaAs at low values of V/III ratio. The substitution of TBAs for AsH3 results in no observable increase in carbon in the epitaxial GaAs. 相似文献
20.
C. H. Wei Z. Y. Xie J. H. Edgar K. C. Zeng J. Y. Lin H. X. Jiang J. Chaudhuri C. Ignatiev D. N. Braski 《Journal of Electronic Materials》2000,29(4):452-456
BxGa1−xN films were deposited on 6H-SiC (0001) substrates at 1000°C by low pressure MOVPE using diborane, trimethylgallium, and ammonia
as precursors. The presence of boron was detected by Auger scanning microprobe, the shift of the (00.2) x-ray diffraction
peak, and low-temperature photoluminescence. A single-phase BxGa1−xN alloy with x=1.5% was produced at the gas phase B/Ga ratio of 0.005. Phase separation into wurtzite BGaN and the B-rich
phase occurred for a B/Ga ratio in the 0.01–0.2 range. Only BN was formed for B/Ga >0.2. The B-rich phase was identified as
h-BN with sp2 bonding based on the results of Fourier transform infrared spectroscopy. As the diborane flow exceeds the threshold concentration,
the growth rate of BGaN decreases sharply, because the growth of GaN is poisoned by the formation of the slow growing BN phase.
The bandedge emission of BxGa1−xN varies from 3.451 eV for x=0% with FWHM of 39.2 meV to 3.465 eV for x=1.5% with FWHM of 35.1 meV. The narrower FWHM indicates
that the quality of GaN epilayer is improved with a small amount of boron incorporation. The PL linewidths become broader
as more boron is introduced into the solid solution. 相似文献