Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

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.

The Influence of Growth Temperature on Oxygen Concentration in GaN Buffer Layer

2008 ◽  
Vol 1068 ◽  
Author(s):  
Ewa Dumiszewska ◽  
Wlodek Strupinski ◽  
Piotr Caban ◽  
Marek Wesolowski ◽  
Dariusz Lenkiewicz ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Oxygen Concentration ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Buffer Layers ◽  
Crystalline Quality ◽  
Temperature Growth ◽  
Gan Buffer Layer

ABSTRACTThe influence of growth temperature on oxygen incorporation into GaN epitaxial layers was studied. GaN layers deposited at low temperatures were characterized by much higher oxygen concentration than those deposited at high temperature typically used for epitaxial growth. GaN buffer layers (HT GaN) about 1 μm thick were deposited on GaN nucleation layers (NL) with various thicknesses. The influence of NL thickness on crystalline quality and oxygen concentration of HT GaN layers were studied using RBS and SIMS. With increasing thickness of NL the crystalline quality of GaN buffer layers deteriorates and the oxygen concentration increases. It was observed that oxygen atoms incorporated at low temperature in NL diffuse into GaN buffer layer during high temperature growth as a consequence GaN NL is the source for unintentional oxygen doping.

Influence of buffer layer thickness and epilayer’s growth temperature on crystalline quality of InAs0.6P0.4/InP grown by LP-MOCVD

2011 ◽  
Vol 151 (12) ◽  
pp. 904-907 ◽  
Author(s):  
Xia Liu ◽  
Hang Song ◽  
Guoqing Miao ◽  
Hong Jiang ◽  
Lianzhen Cao ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Buffer Layer Thickness

Effect of buffer layer thickness and epilayer growth temperature on crystalline quality of InAs0.9Sb0.1 grown by MOCVD

2008 ◽  
Vol 466 (1-2) ◽  
pp. 507-511
Author(s):  
Shuzhen Yu ◽  
Guoqing Miao ◽  
Jianchun Xie ◽  
Yixin Jin ◽  
Tiemin Zhang ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Buffer Layer Thickness

STRUCTURAL STUDY OF PZT/YBCO BY TRIPLE-AXES DIFFRACTION

1999 ◽  
Vol 13 (04) ◽  
pp. 383-387
Author(s):  
Z. H. MAI ◽  
A. I. ZHU ◽  
B. T. LIU ◽  
C. R. LI ◽  
S. F. CUI ◽  
...  
Keyword(s):  
Structural Study ◽  
Lattice Parameter ◽  
Epitaxial Films ◽  
Crystalline Quality ◽  
Ybco Layer ◽  
Different Thickness

The structures of Pb ( Zr x Ti 1-x) O 3/ YBCO heterostructure with different thickness of PZT sublayer were investigated. The lattice parameter, c of YBCO layer is obtained to be c=11.686±0.001 Å, being of 0.2% larger than that of the bulk one. The lattice parameter, c of PZT layer is c=4.116±0.001 Å, indicating that the composition of the sample is Pb ( Zr 0.48 Ti 0.52) O 3. The misorientations of YBCO/PZT sublayers were observed in the samples B and D. The effect of the crystalline quality of the STO substrate on the quality of the YBCO and PZT epitaxial films was discussed.

The crystalline quality of Si films prepared by thermal- and photo-CVD at low temperatures

1995 ◽  
Vol 12 (5) ◽  
pp. 593-596
Author(s):  
Chan-Hwa Chung ◽  
Jae Hyun Han ◽  
Shi-Woo Rhee ◽  
Sang Heup Moon
Keyword(s):  
Low Temperatures ◽  
Crystalline Quality ◽  
Si Films

Phase segregation in GaAs layers grown at low temperature

1991 ◽  
Vol 49 ◽  
pp. 860-861
Author(s):  
Zuzanna Liliental ◽  
Roar Kilaas
Keyword(s):  
Growth Temperature ◽  
Growth Parameters ◽  
Flux Ratio ◽  
Phase Segregation ◽  
Lattice Parameter ◽  
High Resistivity ◽  
Active Device ◽  
Circuit Performance ◽  
Gaas Buffer Layer ◽  
Lt Gaas

GaAs device and circuit performance may be impaired by substrate conduction. One such effect, called sidegating, leads to undesirable cross-talk between neighboring devices. This problem can be avoided by isolating the active device layer from the substrate with a GaAs buffer layer grown by molecular beam epitaxy (MBE) at low temperatures (LT GaAs). The LT GaAs layers show high resistivity, a large trap density, and breakdown strengths about ten times that of semi-insulating GaAs. These layers are grown at a substrate temperature of ~ 200°C. A large (~1 at.%) excess of As in these as-grown layers causes an increase (~0.1%) in the GaAs lattice parameter.The crystal structure of these layers is very sensitive to the growth parameters such as: growth temperature, As/Ga flux ratio and growth rate. With decreasing growth temperature a higher As concentration can be incorporated and only a smaller layer thickness of high crystal perfection can be grown.

Effect of epilayer's growth temperature on crystalline quality of InAs0.6P0.4/InP grown by two-step growth method

2010 ◽  
Vol 506 (2) ◽  
pp. 530-532 ◽  
Author(s):  
Xia Liu ◽  
Hong Jiang ◽  
Guoqing Miao ◽  
Hang Song ◽  
Lianzhen Cao ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Crystalline Quality ◽  
Growth Method ◽  
Step Growth

Effects of Low-Temperature Grown GaAs Intermediate Layers on the Crystalline Quality of GaAs-on-Si Epilayers

1994 ◽  
Vol 340 ◽  
Author(s):  
T.C. Chong ◽  
C.C. Phua ◽  
W.S. Lau ◽  
L.S. Tan
Keyword(s):  
Low Temperature ◽  
Deep Level ◽  
Crystalline Quality ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
X Ray ◽  
Peak Intensity ◽  
Intermediate Layers ◽  
Lt Gaas

ABSTRACTThe incorporation of low-temperature (LT) GaAs intermediate layers grown at 230°C had been shown to have the effects of improving the crystalline quality of GaAs epilayers on Si. The use of this LT-GaAs intermediate layer between the GaAs nucleation layer and the GaAs overlayer has improved the photoluminescence (PL) peak intensity by about five times, and reduced the GaAs (004) X-ray diffraction full width at half maximum (FWHM) by 59 arcsecs. The PL results were subsequently confirmed by cathodoluminescence images. The dominant deep level electron trap in the LT-GaAs epilayer grown on Si substrate was the same as that found in LT-GaAs epilayer grown on GaAs substrate.

Sign in / Sign up

Export Citation Format

Share Document