Growth Kinetics and Thermal Stress in AlN Bulk Crystal Growth

2002 ◽  
Author(s):  
Bei Wu ◽  
Ronghui Ma ◽  
Hui Zhang ◽  
Michael Dudley ◽  
Raoul Schlesser ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Crystal Growth ◽  
Temperature Distribution ◽  
Stress Level ◽  
Grown Crystal ◽  
Power Level ◽  
Chemical Species ◽  
Group Iii Nitrides ◽  
Minor Effect ◽  
Group Iii

Group III nitrides, such as GaN, AlN and InGaN, have attracted a lot of attention due to the development of blue-green and ultraviolet light emitting diodes (LEDs) and lasers. In this paper, an integrated model has developed based on the conservation of momentum, mass, chemical species and energy together with necessary boundary conditions that account for heterogeneous chemical reactions both at the source and seed surfaces. The simulation results have been compared with temperature measurements for different power levels and flow rates in a reactor specially designed for nitride crystal growth at NCSU. It is evident that the heat power level affects the entire temperature distribution greatly while the flow rate has minor effect on the temperature distribution. The results also show that the overall thermal stress level is higher than the critical resolved shear stress, which means thermal elastic stress can be a major source of dislocation density in the as-grown crystal. The stress level is strongly dependent on the temperature gradient in the as-grown crystal. Results are correlated well with defects showing in an X-ray topograph for the AlN wafer.

Effect of Radiation in Solid during SiC Sublimation Growth

2006 ◽  
Vol 911 ◽  
Author(s):  
Shin-ichi Nishizawa ◽  
Shin-ichi Nakashima ◽  
Tomohisa Kato
Keyword(s):  
Thermal Stress ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Absorption Coefficient ◽  
Doping Concentration ◽  
Grown Crystal ◽  
Growth Front ◽  
Growth Features ◽  
Sublimation Growth ◽  
Front Temperature

AbstractThe effect of infrared absorption on SiC sublimation growth was numerically investigated. At first, absorption coefficient was estimated as function of doping concentration. Then temperature distribution inside a crucible was numerically analyzed with taking account of absorption in growing crystal. It was pointed out that temperature distribution in a growing crystal strongly depends on absorption coefficient, i.e. doping concentration. As increasing the absorption coefficient, the growth front temperature and temperature gradient inside a growing crystal increase. It might cause large thermal stress and affect the grown crystal quality. This agrees well with growth features in experiment. The growth condition should be determined with taking account of absorption coefficient, i.e. doping concentration.

The phase and crystal-growth study of group-III nitrides in a 2000°C at 20GPa region

2007 ◽  
Vol 300 (1) ◽  
pp. 26-31 ◽  
Author(s):  
H. Saitoh ◽  
W. Utsumi ◽  
H. Kaneko ◽  
K. Aoki
Keyword(s):  
Crystal Growth ◽  
Group Iii Nitrides ◽  
Growth Study ◽  
Group Iii

scholarly journals Modelling InSb Czochralski Growth

2021 ◽  
Author(s):  
Sean Bohun
Keyword(s):  
Thermal Stress ◽  
Crystal Growth ◽  
Temperature Distribution ◽  
Stefan Problem ◽  
Czochralski Growth ◽  
Experimental Setting

A model of Czrochralski crystal growth is presented that reduces the issue of finding the temperature distribution as a Stefan problem. From the temperature distribution the corresponding distribution of thermal stress inside the growing crystal can be computed. This work will allow the rapid simulation of a variety of crystal growing strategies which would be prohibitively expensive in an experimental setting.

Recent Progress in Crystal Growth and Conductivity Control of Wide Bandgap Group III Nitride Semiconductors

1998 ◽  
Vol 510 ◽  
Author(s):  
I. Akasaki
Keyword(s):  
Crystal Growth ◽  
High Performance ◽  
Recent Progress ◽  
Materials Science ◽  
Green Light ◽  
Group Iii Nitrides ◽  
Wide Bandgap ◽  
Device Fabrication ◽  
Quantum Well Structures ◽  
Group Iii

AbstractRecent progress in crystal growth of wide bandgap group III nitrides on highly-mismatched substrates has enabled us to produce high-quality GaN, A1GaN, GaInN and quantum well structures. High-performance blue and green light-emitting diodes and room temperature operation of nitride-based laser diodes have also been realized. Today, steady progress is being made in the areas of crystal growth and device performance. However, much further advances are required in many areas of materials science and device fabrication of the nitrides

Materials Chemistry and Bulk Crystal Growth of Group III Nitrides in Supercritical Ammonia

1997 ◽  
Vol 495 ◽  
Author(s):  
Joseph W. Kolis ◽  
Steven Wilcenski ◽  
Robert A. Laudise
Keyword(s):  
Crystal Growth ◽  
New Products ◽  
Group Iii Nitrides ◽  
Bulk Crystal ◽  
Materials Chemistry ◽  
Bulk Crystal Growth ◽  
Group Iii ◽  
Gallium Nitrides ◽  
Supercritical Ammonia

ABSTRACTReasonably sized crystals of aluminum and gallium nitrides can be grown in supercritical ammonia using chloride and amide as the mineralizer. Best growth was achieved at 380°C in ammonia at 40,000 psi (270 MPa). Under these conditions crystals as large as 0.4 mm could be grown over several days. Attempts to optimize the identity and concentration of the mineralizer, and the acidity of the solution, led to several new products including A1F3(NH3)2.

Investigation Into Thermal Stress Characteristics of Pipe-in-Pipe Under High Temperature Condition

2018 ◽  
Author(s):  
Si-Hwa Jeong ◽  
Min-Gu Won ◽  
Nam-Su Huh ◽  
Yun-Jae Kim ◽  
Young-Jin Oh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
High Temperature ◽  
Temperature Distribution ◽  
Heat Transfer Analysis ◽  
Piping System ◽  
Curved Pipe ◽  
High Temperature Condition ◽  
Single Pipe ◽  
Radiation Conditions

In this paper, the thermal stress characteristics of the pipe-in-pipe (PIP) system under high temperature condition are analyzed. The PIP is a type of pipe applied in sodium-cooled faster reactor (SFR) and has a different geometry from a single pipe. In particular, under the high temperature condition of the SFR, the high thermal stress is generated due to the temperature gradient occurring between the inner pipe and outer pipe. To investigate the thermal stress characteristics, three cases are considered according to geometry of the support. The fully constrained support and intermediate support are considered for case 1 and 2, respectively. For case 3, both supports are applied to the actual curved pipe. The finite element (FE) analyses are performed in two steps for each case. Firstly, the heat transfer analysis is carried out considering the thermal conduction, convection and radiation conditions. From the heat transfer analysis, the temperature distribution results in the piping system are obtained. Secondly, the structural analysis is performed considering the temperature distribution results and boundary conditions. Finally, the effects of the geometric characteristics on the thermal stress in the PIP system are analyzed.

Trends in Solute Segregation Behavior During Silicon Solidification

1993 ◽  
Vol 321 ◽  
Author(s):  
Riccardo Reitanot ◽  
Patrick M. Smith ◽  
Michael J. Aziz
Keyword(s):  
Crystal Growth ◽  
Inverse Correlation ◽  
High Growth ◽  
Orientation Dependence ◽  
Solute Trapping ◽  
Group Iii ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Crystal Growth Kinetics ◽  
Interface Structures

ABSTRACTAt the high growth rates accessible during pulsed-laser induced melting and solidification and explosive crystallization, crystal growth kinetics are dominated not by equilibrium thermodynamics, but by the atomistic mechanisms by which crystallization proceeds. These Mechanisms can be probed by testing the predictions of solute trapping models based on various crystal/Melt interface structures against Measurements. We have measured the dependence of solute trapping of several group III, IV, and V elements in silicon on both interface orientation and crystallization speed. The Aperiodic Stepwise Growth Model of Goldman and Aziz accurately fits both the velocity and orientation dependence of the solute trapping observed in these systems. The success of the model implies a ledge structure for the crystal/Melt interface and a step-flow mechanism for crystal growth. In addition, we have observed an empirical inverse correlation between the two free parameters (“diffusive speeds”) in this model and the equilibrium solute partition coefficient of a system. This correlation may be used to estimate values of the diffusive speeds for other systems in which solute trapping has not been or cannot be Measured.

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