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1.
S. T. Kim Y. J. Lee D. C. Moon C. Lee H. Y. Park 《Journal of Electronic Materials》1998,27(10):1112-1116
A hydride vapor phase epitaxy was employed to grow the 10∼240 μm thick GaN films on a (111) MgAl2O4 substrate. The GaN films on a MgAl2O4 substrate revealed characteristics of photoluminescence (PL) in impurity doped GaN, which may be due to the out-diffusion
and auto-doping of Mg from the MgAl2O4 substrate during GaN growth. The PL peak energy of neutral donor bound exciton emission and the frequency of Raman E2 mode were decreased by increasing the GaN thickness, due to the residual strain relaxation in the epilayers. The dependence
of Raman E2 mode of GaN films on residual strain can be estimated as Δ ω/Δ σ=3.93 (cm−1/GPa). 相似文献
2.
Hyung Koun Cho Jeong Yong Lee Chi Sun Kim Gye Mo Yang 《Journal of Electronic Materials》2001,30(10):1348-1352
We have studied the influence of indium (In) composition on the structural and optical properties of Inx Ga1−xN/GaN multiple quantum wells (MQWs) with In compositions of more than 25% by means of high-resolution x-ray diffraction (HRXRD),
photoluminescence (PL), and transmission electron microscopy (TEM). With increasing the In composition, structural quality
deterioration is observed from the broadening of the full width athalf maximum of the HRXRD superlattice peak, the broad multiple
emission peaks oflow temperature PL, and the increase of defect density in GaN capping layers and InGaN/GaN MQWs. V-defects,
dislocations, and two types of tetragonal shape defects are observed within the MQW with 33% In composition by high resolution
TEM. In addition, we found that V-defects result in different growth rates of the GaN barriers according to the degree of
the bending of InGaN well layers, which changes the period thickness of the superlattice and might be the source of the multiple
emission peaks observed in the InxGa1−xN/GaN MQWs with high in compositions. 相似文献
3.
Mg- and Si-doped GaN and AlGaN films were grown by metalorganic chemical vapor deposition and characterized by room-temperature
photoluminescence and Hall-effect measurements. We show that the p-type carrier concentration resulting from Mg incorporation
in GaN:Mg films exhibits a nonlinear dependence both on growth temperature and growth pressure. For GaN and AlGaN, n-type
doping due to Si incorporation was found to be a linear function of the silane molar flow. Mg-doped GaN layers with 300K hole
concentrations p ∼2×1018 cm−3 and Si-doped GaN films with electron concentrations n∼1×1019 cm−3 have been grown. N-type Al0.10Ga0.90N:Si films with resistivities as low as p ∼6.6×10−3 Ω-cm have been measured. 相似文献
4.
Yundong Qi Charles Musante Kei May Lau Lesley Smith Rajesh Odedra Ravi Kanjolia 《Journal of Electronic Materials》2001,30(11):1382-1386
Bis(cyclopentadienyl)magnesium (Cp2Mg) is a common source for p-type doping in GaN and AlInGaP materials. It is a white crystalline solid with very low vapor
pressure, leading to transport problems similar to solid trimethyindium (TMI). Some of these problems can be alleviated by
a newly developed source-solution magnesocene, Cp2Mg, dissolved in a solvent that is essentially nonvolatile. In this paper, we report the growth and comparative results of
Mg-doped GaN grown by OMVPE using solid and solution Cp2Mg. Using both sources, we optimized parameters to obtain high-quality GaN growth with hole concentrations up to 1 1018/cm3. 相似文献
5.
M. Pan J. Nause V. Rengarajan R. Rondon E.H. Park I.T. Ferguson 《Journal of Electronic Materials》2007,36(4):457-461
N-doped p-type ZnO thin films were grown on c-sapphire substrates, semi-insulating GaN templates, and n-type ZnO substrates by metal organic chemical vapor deposition (MOCVD). Diethylzinc and oxygen were used as precursors for
Zn and O, respectively, while ammonia (NH3) and nitrous oxide (N2O) were employed as the nitrogen dopant sources. X-ray diffraction (XRD) studies depicted highly oriented N-doped ZnO thin
films. Photoluminescence (PL) measurements showed a main emission line around 380 nm, corresponding to an energy gap of 3.26 eV.
Nitrogen concentration in the grown films was analyzed by secondary ion mass spectrometry (SIMS) and was found to be on the
order of 1018 cm−3. Electrical properties of N-doped ZnO epilayers grown on semi-insulating GaN:Mg templates were measured by the Hall effect
and the results indicated p-type with carrier concentration on the order of 1017 cm−3. 相似文献
6.
Magnesium-doped GaAs has been grown by organometallic vapor phase epitaxy (OM-VPE). Bis (cyclopentadienyl) mag-nesium (Cp2Mg) is used as the organometallic precursor to Mg. The epitaxial layers have been characterized by resis-tivity and Hall measurements,
photoluminescence spectro-scopy and optical microscopy. The material is of high electrical and optical quality; controllable
doping over the range 1015 to 1019cm-3 is reproducibly attained. The ionization energy of the Mg acceptor is determined to be 30 ± 2.5 meV at 77K. Negligible compensation
is observed, consistent with clean thermolysis of the Cp2Mg under growth conditions. GaAs diodes have been fabricated using Mg as the p-dopant and either Se, Si, or Sn as the n-dopant.
The diodes show very low leakage currents under reverse bias, even at relatively high doping levels. Degenerately-doped junctions
for interconnecting monolithic cascade concentrator solar cells have also been successfully grown, displaying forward conductivities
as high as 19 amps V−1 cm-2 at 0.05V forward bias. 相似文献
7.
Xiao M. Fang Yabo Li Dietrich W. Langer James S. Solomon 《Journal of Electronic Materials》1994,23(12):1269-1272
Erbium doped GaAs has been grown by metalorganic chemical vapor deposition using a novel liquid precursor: Tris (n-butylcyclopentadienyl)
erbium, Er(C4H9C5H4)3. Erbium doping as high as 1.2 × 1019cm−3 has been realized. The morphology was excellent at growth temperatures near 620°C. The erbium concentration was found to
depend on growth temperatures due to incomplete pyrolysis of the erbium metalorganic compound. The erbium-related PL intensity
was decreased when the erbium concentration exceeded ∼1.2 × 1019cm−3. 相似文献
8.
Chien-Cheng Yang Pao-Ling Koh Meng-Chyi Wu Chih-hao Lee Gou-Chung Chi 《Journal of Electronic Materials》1999,28(10):1096-1100
GaN epitaxial layers were grown on sapphire substrates in a separate-flow reactor by metalorganic chemical vapor deposition.
The flow-rate ratio of H2 on the upper stream to NH3 on the bottom stream is varied from 0.5 to 2. The growth condition and characterization of the GaN epitaxial layers are investigated
in detail. The H2 flow rate of the upper stream strongly affects the reactant gas flow pattern near the substrate surface and thus influences
the quality of epitaxial layers. At the optimum H2/NH3 flow ratio of 1.0, we can obtain a good quality of GaN epitaxial layers which exhibit a strong near band-edge emis-sion in
the 20 K photoluminescence (PL), a full width at half maximum of 66 meV for the 300 K PL, an electron mobility of 266 cm2/V-s and concentration of 1 × 1018 cm−3 at 300 K. 相似文献
9.
Intentionally undoped and three different, doped layer structures are used to investigate properties of AlGaN/GaN high electron
mobility transistors (HEMTs) before and after SiN passivation. For unpassivated devices, the drain current, transconductance,
cutoff frequency, and microwave output-power increase with increased doping level, in spite of an increase in the gate-leakage
current. After passivation, an overall performance improvement of all devices occurs. The passivation-induced sheet charge
decreases from 2×1012 cm−2 in undoped structures to ∼0.7×1012 cm−2 in higher doped structures and performance improvement with passivation is less pronounced for higher doped devices. However,
the output power of unpassivated and passivated devices on higher doped structures is much higher than that on the undoped-passivated
counter-part. These results underline an advantage of the doped layer structure for the preparation of high-performance AlGaN/GaN
HEMTs. 相似文献
10.
J.P. Liu J.B. Limb J.-H. Ryou W. Lee D. Yoo C.A. Horne R.D. Dupuis 《Journal of Electronic Materials》2008,37(5):558-563
Mg-doped InGaN/GaN p-type short-period superlattices (SPSLs) are developed for hole injection and contact layers of green light-emitting diodes
(LEDs). V-defect-related pits, which are commonly found in an InGaN bulk layer, can be eliminated in an InGaN/GaN superlattice
with thickness and average composition comparable to those of the bulk InGaN layer. Mg-doped InGaN/GaN SPSLs show significantly
improved electrical properties with resistivity as low as ∼0.35 ohm-cm, which is lower than that of GaN:Mg and InGaN:Mg bulk
layers grown under optimized growth conditions. Green LEDs employing Mg-doped InGaN/GaN SPSLs for hole injection and contact
layers have significantly lower reverse leakage current, which is considered to be attributed to improved surface morphology.
The peak electroluminescence intensity of LEDs with a SPSL is compared to that with InGaN:Mg bulk hole injection and contact
layers. 相似文献
11.
M. C. Johnson Z. Liliental-Weber D. N. Zakharov D. E. Mccready R. J. Jorgenson J. Wu W. Shan E. D. Bourret-Courchesne 《Journal of Electronic Materials》2005,34(5):605-611
Temperature-gradient metalorganic chemical vapor deposition (MOCVD) was used to deposit InxGa1−xN/GaN multiple quantum well (MQW) structures with a concentration gradient of indium across the wafer. These MQW structures
were deposited on low defect density (2×108 cm−2) GaN template layers for investigation of microstructural properties and V-defect (pinhole) formation. Room temperature (RT)
photoluminescence (PL) and photomodulated transmission (PT) were used for optical characterization, which show a systematic
decrease in emission energy for a decrease in growth temperature. Triple-axis x-ray diffraction (XRD), scanning electron microscopy,
and cross-sectional transmission electron microscopy were used to obtain microstructural properties of different regions across
the wafer. Results show that there is a decrease in crystal quality and an increase in V-defect formation with increasing
indium concentration. A direct correlation was found between V-defect density and growth temperature due to increased strain
and indium segregation for increasing indium concentration. 相似文献
12.
G. P. Yablonskii A. L. Gurskii E. V. Lutsenko I. P. Marko B. Schineller A. Guttzeit O. Schön M. Heuken K. Heime R. Beccard D. Schmitz H. Juergensen 《Journal of Electronic Materials》1998,27(4):222-228
Photoluminescence (PL) and reflection spectra of undoped and Mg-doped GaN single layers grown on sapphire substrates by metalorganic
vapor phase epitaxy (MOVPE) were investigated in a wide range of temperatures, excitation intensities, and doping levels.
The undoped layers show n-type conductivity (μ=400 cm2/Vs, n=3×1017 cm−3). After annealing at T=600–700°C, the Mg-doped layers showed p-type conductivity determined by the potential-profiling technique.
A small value of the full width at half maximum (FWHM=2.8 meV) of the excitonic emission and a high ratio between excitonic
and deep level emission (≈5300) are evidences of the high layer quality. Two donor centers with activation energies of 35
and 22 meV were observed in undoped layers. A fine structure of the PL band with two narrow lines in the spectral range of
the donor-acceptor pair (DAP) recombination was found in undoped layers. An anomaly was established in the temperature behavior
of two groups of PL lines in the acceptor-bound exciton and in donor-acceptor pair regions in Mg doped layers. The lower energy
line quenched with increasing temperature appreciably faster than the high energy ones. Our data does not agree with the DAP
recombination model. It suggests that new approaches are required to explain the recombination mechanisms in undoped and Mg-doped
GaN epitaxial layers. 相似文献
13.
D. M. Matlock M. E. Zvanut Haiyan Wang Jeffrey R. Dimaio R. F. Davis J. E. van Nostrand R. L. Henry Daniel Koleske Alma Wickenden 《Journal of Electronic Materials》2005,34(1):34-39
Electron paramagnetic resonance (EPR) spectroscopy is used to study the unpassivated Mg-related acceptor in GaN films. As
expected, the trends observed before and after O2, N2, or forming-gas anneals at temperatures <800°C are similar to those typically reported for electrical measurements. However,
annealing at temperatures >850°C in O2 or N2 permanently removes the signal, contrary to the results of conductivity measurements. Approximately 1019 cm−3 Mg acceptors were detected in some GaN films grown by chemical vapor deposition (CVD) before acceptor activation, suggesting
that it is possible to have electrically active Mg in as-grown CVD material. 相似文献
14.
Theodore Chung Jae Limb Jae-Hyun Ryou Wonseok Lee Peng Li Dongwon Yoo Xue-Bing Zhang Shyh-Chiang Shen Russell D. Dupuis David Keogh Peter Asbeck Ben Chukung Milton Feng Dimitri Zakharov Zusanne Lilienthal-Weber 《Journal of Electronic Materials》2006,35(4):695-700
The design and growth of GaN/InGaN heterojunction bipolar transistors (HBTs) by metalorganic chemical vapor deposition (MOCVD)
are studied. Atomic-force microscopy (AFM) images of p+InGaN base layers (∼100 nm) deposited under various growth conditions indicate that the optimal growth temperature is limited
to the range between 810 and 830°C due to a trade-off between surface roughness and indium incorporation. At these temperatures,
the growth pressure must be kept above 300 Torr in order to keep surface pit density under control. An InGaN graded-composition
emitter is adopted in order to reduce the number of V-shaped defects, which appear at the interface between GaN emitter and
InGaN base and render an abrupt emitter-base heterojunction nearly impossible. However, the device performance is severely
limited by the high p-type base contact resistance due to surface etching damage, which resulted from the emitter mesa etch. 相似文献
15.
M. D. Bremser W. G. Perry O. H. Nam D. P. Griffis R. Loesing D. A. Ricks R. F. Davis 《Journal of Electronic Materials》1998,27(4):229-232
Thin films of Si-doped AlxGa1−xN (0.03≤x≤0.58) having smooth surfaces and strong near-band edge cathodoluminescence were deposited at 0.35–0.5 μm/h on on-axis
6H-SiC(0001) substrates at 1100°C using a 0.1 μm AlN buffer layer for electrical isolation. Alloy films having the compositions
of Al0.08Ga0.92N and Al0.48Ga0.52N exhibited mobilities of 110 and 14 cm2/V·s at carrier concentrations of 9.6×1018 and 5.0×1017 cm−3, respectively. This marked change was due primarily to charge scattering as a result of the increasing Al concentration in
these random alloys. Comparably doped GaN films grown under similar conditions had mobilities between 170 and ∼350 cm2/V·s. Acceptor doping of AlxGa1−xN for x≤0.13 was achieved for films deposited at 1100°C. No correlation between the O concentration and p-type electrical
behavior was observed. 相似文献
16.
Z.X. Zhang X.J. Pan T. Wang L. Jia L.X. Liu W.B. Wang E.Q. Xie 《Journal of Electronic Materials》2008,37(8):1049-1053
Nanocrystalline GaN films were prepared by thermal treatment of amorphous GaN films under flowing NH3 at a temperature of 600°C to 950°C for 1 h to 2 h. X-ray diffraction and field-emission scanning electron microscopy confirmed
the formation of high-crystal-quality hexagonal GaN films with preferential (002) orientation. The photoluminescence spectrum
showed a sharp peak near the band gap emission located at 368 nm and a broad blue peak centered at 430 nm. Five first-order
Raman modes near ∼143 cm−1, 535 cm−1, 555 cm−1, 568 cm−1, and 731 cm−1 with two new additional Raman peaks at 257 cm−1 and 423 cm−1 were observed. The origin of these new Raman peaks is discussed briefly. 相似文献
17.
T.J. de Lyon R.D. Rajavel A.T. Hunter J.E. Jensen M.D. Jack S.L. Bailey R.E. Kvaas V.K. Randall S.M. Johnson 《Journal of Electronic Materials》2008,37(9):1420-1425
An initial investigation of the use of atomic nitrogen for controlled p-type doping of wide-bandgap Hg0.3Cd0.7Te (x = 0.7) is reported. Mixtures of argon and nitrogen, ranging in nitrogen concentration from 0.1% to 100%, have been utilized
to demonstrate well-controlled nitrogen incorporation in the 1016 cm−3 to 1020 cm−3 range using total gas flow rates of 0.3 sccm to 4.0 sccm and radiofrequency (RF) powers of 100 W to 400 W. Nitrogen doping
exhibits several desirable attributes including abrupt turn-on and turn-off and minimal sensitivity to variations in growth
temperature and HgCdTe composition, with no negative effects on HgCdTe dislocation density and morphology. Preliminary electrical
measurements indicate primarily n-type behavior in the 1014 cm−3 to 1015 cm−3 range in as-grown x = 0.7 HgCdTe and CdTe films doped with nitrogen at 1018 cm−3 to 1020 cm−3 concentrations, while ZnTe films have exhibited p-type electrical activity with hole concentrations approaching 1020 cm−3. 相似文献
18.
R. D. Dupuis C. J. Eiting P. A. Grudowski H. Hsia Z. Tang D. Becher H. Kuo G. E. Stillman M. Feng 《Journal of Electronic Materials》1999,28(3):319-324
Ion implantation into III–V nitride materials is animportant technology for high-power and high-temperature digital and monolithic
microwave integrated circuits. We report the results of the electrical, optical, and surface morphology of Si ion-implanted
GaN films using furnace annealing. We demonstrate high sheet-carrier densities for relatively low-dose (natoms=5×1014 cm−2) Si implants into AlN/GaN/sapphire heteroepitaxial films. The samples that were annealed at 1150°C in N2 for 5 min exhibited a smooth surface morphology and a sheet electron concentration ns ∼9.0×1013 cm−2, corresponding to an estimated 19% electrical activation and a 38% Si donor activation in GaN films grown on sapphire substrates.
Variable-temperature Hall-effect measurem entsindicate a Si donor ionization energy ∼15 meV. 相似文献
19.
20.
MBE growth and characterization of in situ arsenic doped HgCdTe 总被引:2,自引:0,他引:2
A. C. Chen M. Zandian D. D. Edwall R. E. De Wames P. S. Wijewarnasuriya J. M. Arias S. Sivananthan M. Berding A. Sher 《Journal of Electronic Materials》1998,27(6):595-599
We report the results of in situ arsenic doping by molecular beam epitaxy using an elemental arsenic source. Single Hg1−xCdxTe layers of x ∼0.3 were grown at a lower growth temperature of 175°C to increase the arsenic incorporation into the layers.
Layers grown at 175°C have shown typical etch pit densities of 2E6 with achievable densities as low as 7E4cm−2. Void defect densities can routinely be achieved at levels below 1000 cm−2. Double crystal x-ray diffraction rocking curves exhibit typical full width at half-maximum values of 23 arcsec indicating
high structural quality. Arsenic incorporation into the HgCdTe layers was confirmed using secondary ion mass spectrometry.
Isothermal annealing of HgCdTe:As layers at temperatures of either 436 or 300°C results in activation of the arsenic at concentrations
ranging from 2E16 to 2E18 cm−3. Theoretical fits to variable temperature Hall measurements indicate that layers are not compensated, with near 100% activation
after isothermal anneals at 436 or 300°C. Arsenic activation energies and 77K minority carrier lifetime measurements are consistent
with published literature values. SIMS analyses of annealed arsenic doping profiles confirm a low arsenic diffusion coefficient. 相似文献