Evaluation of Crystalline Quality by Ultraviolet Reflectivity Measurement (UVRM)

1983 ◽  
Vol 130 (10) ◽  
pp. 2047-2049 ◽  
Author(s):  
T. Itoh ◽  
H. Takai
Keyword(s):  
Crystalline Quality ◽  
Reflectivity Measurement

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.

Influences of two-step growth and off-angle Ge substrate on crystalline quality of GaAs buffer layers grown by MOVPE

2015 ◽  
Vol 414 ◽  
pp. 15-20 ◽  
Author(s):  
Pornsiri Wanarattikan ◽  
Sakuntam Sanorpim ◽  
Somyod Denchitcharoen ◽  
Kenjiro Uesugi ◽  
Shigeyuki Kuboya ◽  
...  
Keyword(s):  
Buffer Layers ◽  
Crystalline Quality ◽  
Step Growth

Improved Crystalline Quality of GaN by Substrate Ion Beam Pretreatment

2002 ◽  
Vol 41 (Part 1, No. 6B) ◽  
pp. 4299-4303 ◽  
Author(s):  
Yong Suk Cho ◽  
Junggeun Jhin ◽  
Eui Kwan Koh ◽  
Young Ju Park ◽  
Eun Kyu Kim ◽  
...  
Keyword(s):  
Ion Beam ◽  
Crystalline Quality

Silicon Pillars: Ultrahigh-Crystalline-Quality Silicon Pillars Formed by Millimeter-Wave Annealing of Amorphous Silicon on Glass (Adv. Mater. 29/2009)

2009 ◽  
Vol 21 (29) ◽  
pp. NA-NA
Author(s):  
Fude Liu ◽  
Kim M. Jones ◽  
Yueqin Xu ◽  
William Nemeth ◽  
John Lohr ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Millimeter Wave ◽  
Crystalline Quality ◽  
Silicon Pillars

Online reflectivity measurement of an ultra-weak fiber Bragg grating array

2013 ◽  
Vol 24 (10) ◽  
pp. 105102 ◽  
Author(s):  
Zhihui Luo ◽  
Hongqiao Wen ◽  
Xiaofu Li ◽  
Huiyong Guo
Keyword(s):  
Fiber Bragg Grating ◽  
Bragg Grating ◽  
Reflectivity Measurement ◽  
Grating Array
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