Lattice Mismatch Effects in GaAsP/GaAs and GaAs/GaAsP/GaAs Heterostructures

1989 ◽  
Vol 160 ◽  
Author(s):  
Y.W. Choi ◽  
C.R. Wie ◽  
S.M. Vernon
Keyword(s):  
Layer Thickness ◽  
Full Width Half Maximum ◽  
Lattice Mismatch ◽  
Schottky Diodes ◽  
Tunneling Current ◽  
Field Range ◽  
Rocking Curve ◽  
Fermi Level Pinning ◽  
Gaas Structure ◽  
Epilayer Surface

AbstractStructural and electrical characteristics of the GaAs1-xPx / GaAs and GaAs/GaAs1-xPx/GaAs (x=0.02, 0.05, 0.08, 0.16 and 0.32) hetero-epitaxial systems have been investigated using X-ray rocking curve technique, Optical Beam Induced Current imaging, Nomarski Micrograph, and I-V-T and C-V measurements. The rocking curve Full Width Half Maximum of the GaAs1-xPx epilayer increased sharply at x=0.16 due to a decreased layer thickness and increased in-plane mismatch. The cross-hatched line density in the OBIC image and Nomarski Micrograph increases as the lattice mismatch increases. The epilayer surface morphology is dependent on the layer thickness. The forward I-V characteristics of Au-GaAsP/GaAs and Au-GaAs/GaAsP/GaAs Schottky diodes showed an increased tunneling current for an the increased lattice mismatch. For GaAsP/GaAs structure with a higher phosphorus composition, Fermi-level pinning caused by misfit dislocation was observed. Au-GaAs/GaAsP/GaAs Schottky diodes show an excess current at the low temperature, high field range which, we believe, is due to defect related tunneling.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

Buffer Layer Thickness and the Properties of InN Thin Films on AIN- Seeded (00.1) Sapphire And (111) Silicon

1994 ◽  
Vol 339 ◽  
Author(s):  
T. J. Kistenmacher ◽  
S. A. Ecelberger ◽  
W. A. Bryden
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Electrical Transport ◽  
Lattice Mismatch ◽  
Electrical Mobility ◽  
Seeded Growth ◽  
Electrical Transport Properties ◽  
Buffer Layer Thickness ◽  
Homogeneous Strain

ABSTRACTIntroduction of a buffer layer to facilitate heteroepitaxy in thin films of the Group IIIA nitrides has had a tremendous impact on growth morphology and electrical transport. While AIN- and self-seeded growth of GaN has captured the majority of attention, the use of AIN-buffered substrates for InN thin films has also had considerable success. Herein, the properties of InN thin films grown by reactive magnetron sputtering on AIN-buffered (00.1) sapphire and (111) silicon are presented and, in particular, the evolution of the structural and electrical transport properties as a function of buffer layer sputter time (corresponding to thicknesses from ∼50Å to ∼0.64 μm) described. Pertinent results include: (a) for the InN overlayer, structural coherence and homogeneous strain normal to the (00.1) growth plane are highly dependent on the thickness of the AIN-buffer layer; (b) the homogeneous strain in the AIN-buffer layer is virtually nonexistent from a thickness of 200Å (where a significant X-ray intensity for (00.2)AIN is observed); and (c) the n-type electrical mobility for films on AIN-nucleated (00.1) sapphire is independent of AIN-buffer layer thickness, owing to divergent variations in carrier concentration and film resistivity. These effects are in the main interpreted as arising from a competition between the lattice mismatch of the InN overlayer with the substrate and with the AIN-buffer layer.

Nitrogen-vacancy-related defects and Fermi level pinning in n-GaN Schottky diodes

2003 ◽  
Vol 94 (3) ◽  
pp. 1819-1822 ◽  
Author(s):  
Yow-Jon Lin ◽  
Quantum Ker ◽  
Ching-Yao Ho ◽  
Hsing-Cheng Chang ◽  
Feng-Tso Chien
Keyword(s):  
Fermi Level ◽  
Schottky Diodes ◽  
Nitrogen Vacancy ◽  
Fermi Level Pinning

Accurate Lattice Constant and Mismatch Measurements of SiC Heterostructures by X-Ray Multiple-Order Reflections

2002 ◽  
Vol 742 ◽  
Author(s):  
XianRong Huang ◽  
Michael Dudley ◽  
Philip G. Neudeck ◽  
J. Anthony Powell
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
X Ray Diffraction ◽  
Crystalline Perfection ◽  
Coherent Interface ◽  
Rocking Curve ◽  
X Ray ◽  
Lattice Planes ◽  
Atomically Flat

ABSTRACTHigh-resolution X-ray diffraction (HRXRD) combined with other diffraction techniques is applied to characterize 3C SiC epilayers hoteroepitaxially grown on atomically flat mesas on 4H and 6H SiC substrates. Small-beam rocking curve scan and reciprocal mapping show extremely high crystalline perfection and homogeneity of the ideally grown 3C-SiC epilayers. Accurate lattice measurements based on X-ray multiple-order reflections reveal that: 1) no misorientation between the (0001) lattice planes across the 4H/3C or 6H/3C interface is detected, confirming the 2D nucleation mechanism of the 3C epilayer from a flat coherent interface; 2) in-plane substrate/epilayer lattice mismatch always exists, but the 3C epilayers do not correspond to a completely relaxed cubic structure, indicating that the epilayers are partially strained; 3) lattice mismatch varies for different regions, implying a complicated strain relaxation mechanism of 3C epilayers on various mesas.

X-Ray Double Crystal Diffraction Characterization of Epitaxial Magnetic Transiton Metal Difluorides

1990 ◽  
Vol 187 ◽  
Author(s):  
M. Lui ◽  
A. R. King ◽  
V. Jaccarino ◽  
R. F. C. Farrow ◽  
S. S. P. Parkins
Keyword(s):  
Lattice Mismatch ◽  
Magnetic Transition ◽  
Diffraction Theory ◽  
Epitaxial Films ◽  
Structural Quality ◽  
Double Crystal ◽  
Lattice Match ◽  
Rocking Curve ◽  
X Ray ◽  
Quality Material

AbstractEpitaxial films of a variety of magnetic transition metal difluoride films have been grown by molecular beam epitaxy techniques. The structural quality of these films have been characterized using X-ray double crystal rocking curve analysis. The observed rocking curve linewidths were compared to their intrinsic values as calculated by dynamical diffraction theory. The degree of crystalline perfection as judge by the rocking curves have been correlated with the amount of lattice mismatch between the various epitaxial films and substrates. In the well lattice match case (Δa/a < 0.2%) of epitaxial films of FeF2 and CoF2 grown on (001) ZnF2 substrates, the rocking curve line widths approached their intrinsic limit indicative of extremely high quality material. This work represents some of the best epitaxial magnetic insulating films grown to date.

Barrier height and tunneling current in Schottky diodes with embedded layers of quantum dots

JETP Letters ◽  
2002 ◽  
Vol 75 (2) ◽  
pp. 102-106 ◽  
Author(s):  
A. I. Yakimov ◽  
A. V. Dvurechenskii ◽  
A. I. Nikiforov ◽  
S. V. Chaikovskii
Keyword(s):  
Quantum Dots ◽  
Barrier Height ◽  
Schottky Diodes ◽  
Tunneling Current

Schottky I-V Characteristics of Au/Ni/GaN/SiNx nanonework/sapphire structures

2006 ◽  
Vol 955 ◽  
Author(s):  
Jinqiao Xie ◽  
Yi Fu ◽  
Hadis Morkoç
Keyword(s):  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Schottky Diodes ◽  
Chemical Vapor ◽  
Rocking Curve ◽  
X Ray ◽  
Sapphire Substrates ◽  
Control Samples

ABSTRACTGaN layers on sapphire substrates were grown by metalorganic chemical vapor deposition using in situ porous SiNx nano-network. Crystalline quality of epilayers was characterized by X-ray rocking curve scans, and the full width at hall maximum values for (002) and (102) diffractions were improved from 252 arc sec and 405 arc sec, respectively, in control samples to 216 arc sec and 196 arc sec when SiNx was used. Ni/Au Schottky diodes (SDs) were fabricated and the SD performance was found to be critically dependent on the SiNx coverage (fewer and farther the pores the better the results) which is consistent with the trends of XRD and photoluminescence data. A 1.13eV barrier height was achieved when 5min SiNx layer was used compared with 0.78 eV without any SiNx nanonetwork. Furthermore, the breakdown voltage improved from 76 V to 250V when SiNx nanonetwork was used in otherwise identical structures.

CVD Growth and Characterization of 4H-SiC Epitaxial Film on (11-20) As-Cut Substrates

2005 ◽  
Vol 483-485 ◽  
pp. 113-116 ◽  
Author(s):  
Ze Hong Zhang ◽  
Ying Gao ◽  
Arul Arjunan ◽  
Eugene Toupitsyn ◽  
Priyamvada Sadagopan ◽  
...  
Keyword(s):  
Epitaxial Film ◽  
Schottky Diodes ◽  
Chemical Vapor ◽  
Induced Current ◽  
Cvd Growth ◽  
Electron Beam Induced Current ◽  
Edge Dislocations ◽  
Koh Etching ◽  
Epilayer Surface

Thick epilayers up to 60 µm have been grown on ) 0 2 11 ( face SiC substrates at a growth rate of 15 µm/hr by chemical vapor deposition (CVD). The epilayer surface is extremely smooth with a RMS roughness of 0.6 nm for a 20µm×20µm area. Threading screw and edge dislocations parallel to the c-axis are present in the ) 0 2 11 ( substrate; however, they do not propagate into the epilayer. The I-V characteristics of the Schottky diodes on this face were studied. Basal plane (0001) dislocations with a density of ~105 cm-2 were found in the ) 0 2 11 ( epilayers by molten KOH etching and electron beam induced current (EBIC) mode of the scanning electron microscope (SEM).

BARRIER HEIGHT ENHANCED GaN SCHOTTKY DIODES USING A THIN AlN SURFACE LAYER

2008 ◽  
Vol 22 (29) ◽  
pp. 5167-5173 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN ◽  
F. K. YAM ◽  
C. W. CHIN ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Barrier Height ◽  
Schottky Diode ◽  
Dark Current ◽  
Lattice Mismatch ◽  
Schottky Diodes ◽  
Wide Band ◽  
Hexagonal Wurtzite Structure ◽  
Full Characterization ◽  
Si Substrates

Gallium nitride (GaN) is a highly promising wide band gap semiconductor with applications in high power electronic and optoelectronic devices. Thin films of GaN are most commonly grown in the hexagonal wurtzite structure on sapphire substrates. Growth of GaN onto silicon substrates offers a very attractive opportunity to incorporate GaN devices onto silicon-based integrated circuits. Although direct epitaxial growth of GaN films on Si substrates is a difficult task (mainly due to the 17% lattice mismatch present), substantial progress in the crystal quality can be achieved using a buffer layer. A full characterization of the quality of the material needs to be assessed by a combination of different techniques. In this work, a thin AlN cap layer of 50 nm was incorporated in GaN Schottky diode to enhance the effective Schottky barrier height and reduces the dark current. A barrier height of 0.52 eV for normal GaN Schottky diode was increased to the effective barrier height of 0.63 eV. The resulting Schottky diodes show a dark current of as low as 6.3×10-5 A at 5 V bias, which is about two orders of magnitude lower than that of normal GaN (5.2×10-3 A at 5 V bias) Schottky diode.

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