Effect Of Atomic-Hydrogen Treatment Of (001) Gaas Substrate At “High Temperatures” On Rf Plasma-Assisted Molecular Beam Epitaxy Of Cubic Gan

1997 ◽  
Vol 482 ◽  
Author(s):  
A. Yoshikawah ◽  
H. Nagano ◽  
Z. X. Qiny ◽  
Y. Sugure ◽  
A. W. Jia ◽  
...  
Keyword(s):  
Buffer Layer ◽  
High Temperatures ◽  
Gaas Surface ◽  
Rf Plasma ◽  
Growth Stages ◽  
Hydrogen Treatment ◽  
Initial Growth ◽  
High Quality ◽  
Cubic Gan ◽  
Atomically Flat

AbstractsGrowth of high quality c-GaN on atomic-H treated (001) GaAs was examined by rf plasma-assisted MBE. First the initial growth stages (atomic-H treatment of GaAs, nitridation/deposition of a thin GaN buffer layer, the post deposition annealing of the buffer layer, and epitaxy of c-GaN) were studied by RHEED and AFM observations. It was found that atomically flat GaAs surface with one monolayer-height steps and ragged step edges could be obtained by the atomic-H treatment at high temperatures. It was found that the atomic-H treated GaAs surface was preferable to grow high quality c-GaN; the FWHM of the X-ray rocking curve for the (002) c-GaN was as small as 70 – 90 arcsec.

MBE Growth of Device-Quality Cubic GaN on Atomically Flat (001) GaAs Prepared by Atomic-Hydrogen Treatment at High Temperatures

1998 ◽  
Vol 264-268 ◽  
pp. 1221-1224 ◽  
Author(s):  
Akira Yoshikawa ◽  
Zuo Xiang Qin ◽  
H. Nagano ◽  
Y. Sugure ◽  
A.W. Jia ◽  
...  
Keyword(s):  
High Temperatures ◽  
Atomic Hydrogen ◽  
Hydrogen Treatment ◽  
Mbe Growth ◽  
Cubic Gan ◽  
Atomically Flat

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

Atomically flat (001)GaAs surface prepared by two-step atomic-hydrogen treatment and its application to heteroepitaxy of GaN

1998 ◽  
Vol 189-190 ◽  
pp. 265-269 ◽  
Author(s):  
Hajime Nagano ◽  
Zhixin Qin ◽  
Anwei Jia ◽  
Yoshinori Kato ◽  
Masakazu Kobayashi ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Gaas Surface ◽  
Hydrogen Treatment ◽  
Atomically Flat

High-Resolution X-Ray Diffraction Analysis of “Devicequality” Cubic GaN Grown on (001)GaAs Substrate Prepared by Atomic-Hydrogen Treatment At “High Temperatures”

1997 ◽  
Vol 482 ◽  
Author(s):  
A. Yoshikawa ◽  
Z. X. Qin ◽  
H. Nagano ◽  
Y. Sugure ◽  
A. W. Jia ◽  
...  
Keyword(s):  
High Resolution ◽  
High Temperatures ◽  
Atomic Hydrogen ◽  
Plasma Source ◽  
Hydrogen Treatment ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Cubic Gan ◽  
First Time

AbstractCubic GaN (c-GaN) layers were grown by if-plasma source MBE on (001) GaAs prepared by atomic-hydrogen treatment at “high temperatures”, and the structural properties of the epilayers were investigated by the high-resolution X-ray rocking curve and the reciprocal space mapping measurements. The growth temperature was varied from 620 to 740°C. It was found that single domain “device-quality” c-GaN layers could be grown for the first time; the FWHM of the X-ray rocking curves for the (002) c-GaN could be as small as 70 - 90 arcsec and the inclusion of h-GaN phase in the c-GaN epilayers grown at temperatures above 680°C could be less than 4×10-3.

scholarly journals Growth Of High Quality GaN Thin Films By MBE On Intermediate-temperature Buffer Layers

2000 ◽  
Vol 5 (1) ◽  
Author(s):  
W.K. Fong ◽  
C. F. Zhu ◽  
B. H. Leung ◽  
Charles Surya
Keyword(s):  
Low Temperature ◽  
Buffer Layer ◽  
Electron Mobility ◽  
Unique Feature ◽  
Growth Conditions ◽  
Intermediate Temperature ◽  
Buffer Layers ◽  
Rf Plasma ◽  
Epitaxial Layers ◽  
High Quality

We report the growth of high quality GaN epitaxial layers by rf-plasma MBE. The unique feature of our growth process is that the GaN epitaxial layers are grown on top of a double layer that consists of an intermediate-temperature buffer layer (ITBL), which is grown at 690°C and a conventional low-temperature buffer layer deposited at 500°C. It is observed that the electron mobility increases steadily with the thickness of the ITBL, which peaks at 377 cm2V−1s−1 for an ITBL thickness of 800 nm. The PL also demonstrated systematic improvements with the thickness of the ITBL. Our analyses of the mobility and the photoluminescence characteristics demonstrate that the utilization of an ITBL in addition to the conventional low-temperature buffer layer leads to the relaxation of residual strain within the material resulting in improvement in the optoelectronic properties of the films. A maximum electron mobility of 430 cm2V−1s−1 can be obtained using this technique and further optimizing the growth conditions for the low-temperature buffer layer.

Heteroepitaxial growth of tungsten oxide films on silicon(100) using a BaF2 buffer layer

2003 ◽  
Vol 18 (12) ◽  
pp. 2859-2868 ◽  
Author(s):  
L.D. Doucette ◽  
F. Santiago ◽  
S.L. Moran ◽  
R.J. Lad
Keyword(s):  
Buffer Layer ◽  
Electron Cyclotron Resonance ◽  
Film Growth ◽  
Diffusion Processes ◽  
Electron Beam Evaporation ◽  
Growth Stages ◽  
Initial Growth ◽  
Heteroepitaxial Growth ◽  
Lattice Matching ◽  
Barium Tungstate

Multidomained heteroepitaxial WO3 films were grown on Si(100) substrates using a (111)-oriented BaF2 buffer layer at the WO3–Si interface. The 30-nm-thick BaF2 layer, grown by very low rate molecular-beam epitaxy, consisted of four equivalent crystalline domains oriented about the BaF2[111] axis, which provided templates for heteroepitaxial WO3 film growth. The WO3 films were grown by electron cyclotron resonance oxygen plasma-assisted electron beam evaporation of a WO3 source, and the temperature range was varied between 25°C and 600°C. At an optimal deposition temperature of approximately 450°C, monoclinic-phase WO3 films were produced, which consisted of coexisting (002), (020), and (200) in-plane orientations with respect to the BaF2(111)/Si(100) substrate. During growth, an interfacial barium tungstate (BaWO4) reaction product formed at the WO3–BaF2 interface. The {112} planes of this BaWO4 layer also have a multidomained heteroepitaxial orientation with respect to the BaF2(111) buffer layer. Postdeposition annealing experiments in air for 24 h at 400°C indicated that the heteroepitaxial BaWO4 and WO3 layers remain stable. A thermodynamic argument is used to explain the BaWO4 interfacial reaction during initial growth stages, and kinetically limited diffusion processes through the BaWO4layer coupled with lattice matching across the WO3–BaWO4 interface are proposed to be responsible for the formation of stable WO3 films at later growth stages.

New buffer layer technique using underlying epitaxial AlN films for high-quality GaN growth

2001 ◽  
Vol 693 ◽  
Author(s):  
Tomohiko Shibata ◽  
Yoshihiro Kida ◽  
Hideto Miyake ◽  
Kazumasa Hiramatsu ◽  
Keiichiro Asai ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Threading Dislocations ◽  
Full Width ◽  
High Quality ◽  
Edge Type ◽  
Rocking Curve ◽  
X Ray ◽  
Aln Film ◽  
Layer Technique ◽  
Atomically Flat

AbstractWe demonstrate high-quality epitaxial AlN films on C-plane sapphire as a new buffer layer technique for the growth of high-quality GaN. The obtained GaN films were atomically flat and the full width at half maximum (FWHM) values of the X-ray rocking curve (XRC) were 120arcsec and 510arcsec for (0004) and (10-10), respectively. XRC-FWHM values of the underlying AlN film were 90arcsec and 1800arcsec for (0004) and (10-10), respectively. The XRC results of the GaN indicated that tilted mosaicity of the GaN was much smaller than that of conventional GaN and that small tilted mosaicity coincided with small twisted mosaicity. It was characteristic that the twisted mosaicity drastically reduced from the AlN to the GaN. According to TEM results, it was clarified that the high-quality AlN layer had an effect in reducing the amount of screw-type threading dislocations and that the GaN/AlN interface played an important role in reducing the amount of edge-type dislocations.

scholarly journals Исследование встроенных электрических полей на интерфейсе GaSe/GaAs методом спектроскопии фотоотражения

2020 ◽  
Vol 54 (10) ◽  
pp. 1011
Author(s):  
О.С. Комков ◽  
С.А. Хахулин ◽  
Д.Д. Фирсов ◽  
П.С. Авдиенко ◽  
И.В. Седова ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Electric Fields ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Growth Stages ◽  
Initial Growth ◽  
Lower Efficiency ◽  
Gaas Buffer Layer

The built-in electric fields are generated at the GaSe/GaAs heterointerface when GaSe layers are grown by molecular beam epitaxy on GaAs(001) substrates. The existence of these fields is indicated by the clearly observed Franz–Keldysh oscillations in the photoreflectance spectra. The different values of the intensities of these fields (within the 9.8−17.6 kV/cm range) can be associated both with the diffusion of Se atoms into the GaAs substrate (or into the GaAs buffer layer) and the formation of transition sub-monolayers at initial growth stages. No built-in fields were observed at the GaSe/GaAs heterointerface in case of GaSe layers grown on GaAs(111)B and GaAs(112) substrates, which can be explained by the lower efficiency of Se penetration into these substrates in contrast to GaAs(001).

Sign in / Sign up

Export Citation Format

Share Document