Plasma-Assisted MBE of GaN and AlGaN on 6H SiC(0001)

1995 ◽  
Vol 395 ◽  
Author(s):  
S. Sinharoy ◽  
A. K. Agarwal ◽  
G. Augustine ◽  
L. B. Rowland ◽  
R. L. Messham ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Reverse Bias ◽  
Secondary Ion Mass Spectrometry ◽  
Operating Temperature ◽  
Leakage Currents ◽  
Activation Rate ◽  
P Type ◽  
A1n Buffer Layer ◽  
Secondary Ion

ABSTRACTThe growth of undoped and doped GaN and AlGaN films on off-axis 6H SiC substrates was investigated using plasma-assisted molecular beam epitaxy (MBE). Smooth and crack-free GaN and AlGaN films were obtained; the best results occurred at the highest growth temperature studied (800°C) and with a 40 to 50 nm A1N buffer layer grown at the same temperature. Carrier concentrations of up to n = 4 × 1020 cm−3 were accomplished with silicon, with a 40 to 50% activation rate as determined by secondary ion mass spectrometry (SIMS). Unintentionally doped AlxGa,.xN (x≈0.1) was n-type with a carrier concentration of 7 × 1018 cm−3. N-type AlGaN (x≈0.1)/p-type 6H SiC (0001) heterostructures showed excellent junction characteristics with leakage currents of less than 0.1 nA at 5 V reverse bias at room temperature and 0.5 nA at 200°C operating temperature.

A Comparison of Magnesium and Beryllium Acceptors in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
A.J. Ptak ◽  
T.H. Myers ◽  
Lijun Wang ◽  
N.C. Giles ◽  
M. Moldovan ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Secondary Ion Mass Spectrometry ◽  
Rf Plasma ◽  
Dopant Incorporation ◽  
Optical Activation ◽  
P Type ◽  
Kinetics Of ◽  
Secondary Ion

ABSTRACTStep-doped structures of both magnesium and beryllium were grown in GaN and analyzed using secondary ion mass spectrometry. Dopant incorporation was studied as a function of substrate temperature and dopant flux for Ga-polarity and N-polarity GaN. Incorporation is different for each polarity, with Mg incorporating by up to a factor of 20 times more (30 times more with atomic hydrogen) on the Ga-face, while Be incorporates more readily on the N-face. The effect of atomic hydrogen on the incorporation kinetics of both Mg and Be is also discussed. Mg and Be both undergo surface segregation during growth. Photoluminescence measurements suggest that Be is a p-type dopant with an optical activation energy of approximately 100 meV.

Analyses of High Leakage Currents in Al+ Implanted 4H SiC pn Diodes Caused by Threading Screw Dislocations

2010 ◽  
Vol 645-648 ◽  
pp. 913-916 ◽  
Author(s):  
Takashi Tsuji ◽  
T. Tawara ◽  
Ryohei Tanuma ◽  
Yoshiyuki Yonezawa ◽  
Noriyuki Iwamuro ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Implantation Dose ◽  
Heat Radiation ◽  
Leakage Currents ◽  
Screw Dislocations ◽  
X Ray ◽  
Maximum Electric Field ◽  
Almost All ◽  
P Type ◽  
Secondary Ion

The authors fabricated pn diodes with Al+ implantation in p-type epitaxial layers, and investigated the influence of the implantation dose on reverse leakage currents. Only in the highest dose with the Al concentration of 2x1020cm-3, more than 90% of the devices showed high leakage currents above 10-4A at the maximum electric field of 3MV/cm. In such devices, almost all of the emissive spots corresponded to threading screw dislocations (TSDs) by the analysis of emission microscopy and X-ray topography. These TSDs were defined as killer defects with the estimated density of 500cm-2 in the case of the highest dose. The emissions were supposed to be due to microplasmas, since the spectra of the emissions were different from those of heat radiation. Condensation of Al atoms, nitrogen atoms and DI defects were excluded as the origin of the emissions by secondary ion mass spectrometry and low temperature photoluminescence analyses.

The Properties of n-ZnO/p-SiC Heterojunctions and their Potential Applications for Devices

2006 ◽  
Vol 527-529 ◽  
pp. 1571-1574 ◽  
Author(s):  
Cole W. Litton ◽  
Ya.I. Alivov ◽  
D. Johnstone ◽  
Ümit Özgür ◽  
V. Avrutin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Reverse Bias ◽  
Zno Films ◽  
Turn On ◽  
Forward Current ◽  
Current Voltage ◽  
Potential Applications ◽  
Current Voltage Characteristics ◽  
P Type

Heteroepitaxial n-ZnO films have been grown on commercial p-type 6H-SiC substrates by plasma-assisted molecular-beam epitaxy, and n-ZnO/p-SiC heterojunction mesa structures have been fabricated and their photoresponse properties have been studied. Current-voltage characteristics of the structures had a very good rectifying diode-like behavior with a leakage current less than 2 x 10-4 A/cm2 at -10 V, a breakdown voltage greater than 20 V, a forward turn on voltage of ∼5 V, and a forward current of ∼2 A/cm2 at 8 V. Photosensitivity of the diodes, when illuminated from ZnO side, was studied at room temperature and photoresponsivity of as high as 0.045 A/W at -7.5 V reverse bias was observed for photon energies higher than 3.0 eV.

Heavy Phosphorus Implantation of Ge0.83Si0.17 Epitaxial Layers

1985 ◽  
Vol 45 ◽  
Author(s):  
J.C. Bean ◽  
A.T. Fiory ◽  
L.C. Hopkins
Keyword(s):  
Thermal Processing ◽  
Electrical Transport ◽  
Room Temperature ◽  
Molecular Beam ◽  
Secondary Ion Mass Spectrometry ◽  
Solid Phase ◽  
Rapid Thermal Processing ◽  
Electrical Activation ◽  
Temperature Dependent ◽  
Secondary Ion

ABSTRACTEpitaxial Ge-Si alloy films were grown on Si(100) by molecular beam epitaxy, subsequently given a shallow P implant, and subjected to rapid thermal processing. Heat treatment causes solid-phase epitaxial regrowth of the amorphized implanted layer similar to the case of pure Ge. Phosphorus redistribution, loss, and trapping at the Ge-Si/Si interface are also observed. Anomalous electrical activation is observed for P concentrations below 1 at.%, where the-carriers are either trapped or compensated at room temperature, but not below 100K. Analyses were carried out by Rutherford backscattering and channeling, secondary ion mass spectrometry, and temperature-dependent electrical transport.

Channeled Implantations of p-Type Dopants into 4H-SiC at Different Temperatures

2019 ◽  
Vol 963 ◽  
pp. 382-385 ◽  
Author(s):  
Margareta K. Linnarsson ◽  
Anders Hallén ◽  
Lasse Vines ◽  
Bengt G. Svensson
Keyword(s):  
Room Temperature ◽  
Depth Distribution ◽  
Elevated Temperatures ◽  
Secondary Ion Mass Spectrometry ◽  
Lattice Vibrations ◽  
Simulation Code ◽  
Different Temperatures ◽  
P Type ◽  
Secondary Ion ◽  
Collision Approximation

Channeling of B and Al ions in 4H-SiC(0001), has been investigated by secondary ion mass spectrometry (SIMS). Ion implantations have been performed between room temperature (RT) and 600 °C at various fluences. Before implantation, the major crystal axes were determined and the sample was aligned using the blocking pattern of backscattered protons. As expected, the depth distribution of the implanted ions along a crystal direction penetrates much deeper compared to non-channeling directions. At elevated temperatures, the channeling depth for 100 keV Al-ions is decreased due to lattice vibrations. For 50 keV B-ions, the temperature effect is minor, indicating a smaller interaction between target atoms and B. Simulations has been performed using SIIMPL, a Monte Carlo simulation code based on the binary collision approximation, to predict experimental data and get a deeper insight in the channeling process.

Near-Surface Aggregation of Sn In Heavily Sn-Doped GaAs Films Grown By Molecular Beam Epitaxy

1985 ◽  
Vol 43 ◽  
pp. 368-369
Author(s):  
S. H. Chen
Keyword(s):  
Molecular Beam Epitaxy ◽  
Cross Section ◽  
Electron Spectroscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Secondary Ion Mass Spectrometry ◽  
Specimen Preparation ◽  
Near Surface ◽  
Gaas Films ◽  
Secondary Ion

Sn has been used extensively as an n-type dopant in GaAs grown by molecular-beam epitaxy (MBE). The surface accumulation of Sn during the growth of Sn-doped GaAs has been observed by several investigators. It is still not clear whether the accumulation of Sn is a kinetically hindered process, as proposed first by Wood and Joyce, or surface segregation due to thermodynamic factors. The proposed donor-incorporation mechanisms were based on experimental results from such techniques as secondary ion mass spectrometry, Auger electron spectroscopy, and C-V measurements. In the present study, electron microscopy was used in combination with cross-section specimen preparation. The information on the morphology and microstructure of the surface accumulation can be obtained in a fine scale and may confirm several suggestions from indirect experimental evidence in the previous studies.

GalnAsSb Materials for Thermophotovoltaics

1996 ◽  
Vol 450 ◽  
Author(s):  
C. A. Wang ◽  
G. W. Turner ◽  
M. J. Manfra ◽  
H. K. Choi ◽  
D. L. Spears
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Hole Concentration ◽  
Organometallic Vapor Phase Epitaxy ◽  
Room Temperature Photoluminescence ◽  
P Type ◽  
First Time ◽  
Lattice Matched ◽  
Comparable Quality ◽  
Peak Emission

ABSTRACTGai1−xInxASySb1-y (0.06 < x < 0.18, 0.05 < y < 0.14) epilayers were grown lattice-matched to GaSb substrates by low-pressure organometallic vapor phase epitaxy (OMVPE) using triethylgallium, trimethylindium, tertiarybutylarsine, and trimethylantimony. These epilayers have a mirror-like surface morphology, and exhibit room temperature photoluminescence (PL) with peak emission wavelengths (λP,300K) out to 2.4 μm. 4K PL spectra have a full width at half-maximum of 11 meV or less for λP,4K < 2.1 μm (λP,300K = 2.3 μm). Nominally undoped layers are p-type with typical 300K hole concentration of 9 × 1015 cm−3 and mobility ∼ 450 to 580 cm2/V-s for layers grown at 575°C. Doping studies are reported for the first time for GalnAsSb layers doped n type with diethyltellurium and p type with dimethylzinc. Test diodes of p-GalnAsSb/n-GaSb have an ideality factor that ranges from 1.1 to 1.3. A comparison of electrical, optical, and structural properties of epilayers grown by molecular beam epitaxy indicates OMVPE-grown layers are of comparable quality.

Determination of the Distribution of Ion Implantation Boron in Silicon

2000 ◽  
Vol 650 ◽  
Author(s):  
Te-Sheng Wang ◽  
A.G. Cullis ◽  
E.J.H. Collart ◽  
A.J. Murrell ◽  
M.A. Foad
Keyword(s):  
Electron Microscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Low Energy ◽  
Concentration Profiles ◽  
Impurity Profile ◽  
Transmission Electron ◽  
Device Applications ◽  
P Type ◽  
Secondary Ion

ABSTRACTBoron is the most important p-type dopant in Si and it is essential that, especially for low energy implantation, both as-implanted B distributions and those produced by annealing should be characterized in very great detail to obtain the required process control for advanced device applications. While secondary ion mass spectrometry (SIMS) is ordinarily employed for this purpose, in the present studies implant concentration profiles have been determined by direct B imaging with approximately nanometer depth and lateral resolution using energy-filtered imaging in the transmission electron microscopy. The as-implanted B impurity profile is correlated with theoretical expectations: differences with respect to the results of SIMS measurements are discussed. Changes in the B distribution and clustering that occur after annealing of the implanted layers are also described.

Ferromagnetic and Paramagnetic Semiconductors Based upon GaN, AlGaN, and GaP

2001 ◽  
Vol 690 ◽  
Author(s):  
Mark E. Overberg ◽  
Gerald T. Thaler ◽  
Rachel M. Frazier ◽  
Brent P. Gila ◽  
Cammy R. Abernathy ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Hysteretic Behavior ◽  
Ferromagnetic Semiconductors ◽  
Temperature Dependent ◽  
Paramagnetic Behavior ◽  
Gas Source ◽  
P Type ◽  
First Time ◽  
Temperature Dependent Magnetization

ABSTRACTEpitaxial growth of the ferromagnetic semiconductors GaMnP:C and GaMnN has been investigated by Gas Source Molecular Beam Epitaxy (GSMBE). GaMnP:C films grown with 9.4% Mn are found to be p-type with hysteretic behavior to room temperature. GaMnN films grown at 700 °C with 2.8% Mn show hysteresis at 300 K, while temperature-dependent magnetization measurements indicate that the magnetism may persist to much higher temperatures (> 325 K). Samples of AlGaMnN have also been prepared for the first time that show improved surface morphology compared to GaMnN but which show only paramagnetic behavior.

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