scholarly journals Simulation and Experiment for Growth of High-Quality and Large-Size AlN Seed Crystals by Spontaneous Nucleation

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3939
Author(s):  
Zuoyan Qin ◽  
Wenhao Chen ◽  
Danxia Deng ◽  
Zhenhua Sun ◽  
Baikui Li ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Single Crystal ◽  
Growth Surface ◽  
Inversion Method ◽  
High Quality ◽  
Radial Temperature ◽  
Heater Power ◽  
Seed Crystals ◽  
Spontaneous Nucleation ◽  
Large Size

Seed crystals are the prerequisite for the growth of high quality and large size aluminum nitride (AlN) single crystal boules. The physical vapor transport (PVT) method is adopted to grow AlN seed crystal. However, this method is not available in nature. Herein, the temperature field distribution in the PVT furnace was simulated using the numerical analysis method to obtain free-standing and large-size seeds. The theoretical studies indicate that the temperature distribution in the crucible is related to the crucible height. According to the theory of growth dynamics and growth surface dynamics, the optimal thermal distribution was achieved through the design of a specific crucible structure, which is determined by the ratio of top-heater power to main-heater power. Moreover, in our experiment, a sole AlN single crystal seed with a length of 12 mm was obtained on the tungsten (W) substrate. The low axial temperature gradient between material source and substrate can decrease the nucleation rate and growth rate, and the high radial temperature gradient of the substrate can promote the expansion of crystal size. Additionally, the crystallinity of the crystals grown under different thermal field conditions are analyzed and compared. The Raman results manifest the superiority of the thermal inversion method in the growth of high quality AlN single crystal.

scholarly journals Homogenization of Radial Temperature by a Tungsten Sink in Sublimation Growth of 45 mm AlN Single Crystal

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5553
Author(s):  
Yue Yu ◽  
Botao Liu ◽  
Xia Tang ◽  
Sheng Liu ◽  
Bing Gao
Keyword(s):  
Thermal Stress ◽  
Crystal Growth ◽  
Heat Exchange ◽  
Single Crystal ◽  
Numerical Experiments ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Large Size ◽  
Sublimation Growth

To reduce the thermal stress during the sublimation growth of 45 mm AlN single crystal, a tungsten sink was put on the top of the crucible lid. Numerical experiments showed that the radial temperature gradient was reduced due to the homogenization effect on temperature as a result of the sink. Therefore, this simple tungsten sink method has the potential to grow large-size AlN ingots with fewer cracks. It also reveals that enhancing the heat exchange of the crucible lid is an effective way to improve the quality of crystal growth.

Studies on HPHT synthesis and N defects of N-rich B-doped diamonds

CrystEngComm ◽  
2018 ◽  
Vol 20 (44) ◽  
pp. 7109-7113 ◽  
Author(s):  
Xinyuan Miao ◽  
Liangchao Chen ◽  
Hongan Ma ◽  
Chao Fang ◽  
Longsuo Guo ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Single Crystal ◽  
High Quality ◽  
Temperature Conditions ◽  
Ni Content ◽  
Growth Method

In this paper, high-quality N-rich single crystal diamonds with different boron additive contents were synthesized in NiMnCo alloy with high Ni content by the temperature gradient growth method under HPHT (high pressure and high temperature) conditions.

Large-size and high-quality Zn2TiO4 single crystal grown by the optical floating zone method

2010 ◽  
Vol 312 (24) ◽  
pp. 3561-3563 ◽  
Author(s):  
Liang Li ◽  
Hang Yang ◽  
Dejun Wang ◽  
Guanlin Feng ◽  
Benxian Li ◽  
...  
Keyword(s):  
Single Crystal ◽  
Floating Zone ◽  
Zone Method ◽  
High Quality ◽  
Floating Zone Method ◽  
Large Size

Effect of the Seed Polarity for High Quality 4H-SiC Crystal Grown on 6H-SiC Seed by PVT Method

2011 ◽  
Vol 679-680 ◽  
pp. 44-47
Author(s):  
Im Gyu Yeo ◽  
Tae Woo Lee ◽  
Jong Hwi Park ◽  
Woo Sung Yang ◽  
Heui Bum Ryu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Single Crystal ◽  
Seed Crystal ◽  
Crystal Quality ◽  
High Quality ◽  
Seed Crystals ◽  
Opposite Face ◽  
Crystal Region ◽  
Sublimation Technique

The single crystal ingots by using a sublimation technique were grown on 6H-SiC dual-seed crystals with opposite face polarities and then SiC crystal wafers sliced from the SiC ingot were systematically investigated to find out the polarity dependence of the crystal quality. The growth rate of the SiC crystal grown in this study was about 0.2mm/hr. N-type 2’’ SiC crystals exhibiting the 4H- and 6H-SiC polytype were successfully fabricated on C-face and Si-face, respectively. The incorporation of nitrogen donors in the SiC crystals grown on the C-face seed crystal was exhibited to be higher than in SiC crystals grown on a Si-face crystal. When the SiC crystal ingot proceeded to grow, the SiC crystal region grown on the C-face seed crystal was enlarged compared to the SiC crystal region on the Si-face seed crystal.

scholarly journals The Effect of the Crucible on the Temperature Distribution for the Growth of a Large Size AlN Single Crystal

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 54
Author(s):  
Yue Yu ◽  
Botao Liu ◽  
Xia Tang ◽  
Botao Song ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Crystal Size ◽  
Tantalum Carbide ◽  
Crucible Wall ◽  
Specific Effects ◽  
Large Size ◽  
Axial Temperature ◽  
Growth System

The appropriate distribution of temperature in the growth system is critical for obtaining a large size high quality aluminum nitride (AlN) single crystal by the physical vapor transport (PVT) method. As the crystal size increases, the influence of the crucible on the temperature distribution inside the growth chamber becomes greater. In order to optimize the field of temperature and study the specific effects of various parts of the crucible on the large size AlN single crystal growth system, this study carried out a series of numerical simulations of the temperature field of two crucibles of different materials and put forward the concept of a composite crucible, which combines different materials in the crucible parts. Four composite crucible models were established with different proportions and positions of tantalum carbide (TaC) parts and graphite parts in the crucible. Calculations reveal that different parts of the crucible have different effects on the internal temperature distribution. The axial temperature gradient at the crystal was mainly governed by the crucible wall, whereas the temperature gradient was determined by the integrated effect of the crucible lid and the crucible wall in the radial direction. One type of composite crucible was chosen to minimize the thermal stress in grown AlN crystal, which is applicable to the growth of large sized AlN crystals in the future; it can also be used to grow AlN single crystals at present as well.

Single Crystal Growth of Large-Size and High-Quality NpCoGa5and Its Electrical and Magnetic Properties

2004 ◽  
Vol 73 (7) ◽  
pp. 1665-1668 ◽  
Author(s):  
Dai Aoki ◽  
Yoshiya Homma ◽  
Yoshinobu Shiokawa ◽  
Etsuji Yamamoto ◽  
Akio Nakamura ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
High Quality ◽  
Electrical And Magnetic Properties ◽  
Large Size

Influence of carbon convection field on high quality large single crystal diamonds morphology under high pressure and high temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 40330-40335 ◽  
Author(s):  
Yadong Li ◽  
Xiaopeng Jia ◽  
Bingmin Yan ◽  
Ning Chen ◽  
Chao Fang ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Large Single Crystal ◽  
High Quality

The temperature and convection fields of a catalyst with three different heights were simulated in a temperature gradient growth (TGG) system under high pressure and high temperature (HPHT) conditions.

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