Point Defects and Clusters in Cz Si
Reduction of crystal originated particles (COP) and bulk micro defects (BMD) is important for both solar grade and electronic grade Si. Obtaining low COP or COP-free silicon wafers is a common market demand. However, controlling the concentration of COPs and BMDs is not so straightforward since both can be affected by the crystal pulling rate, thermal gradients in the crystal, crystal/melt interface shape, etc.
CGSim package includes models of defect evolution based on the Kulkarni and Voronkov approaches. As you can see from the comparison of the results obtained using CGSim package with the experimental data (right), modeling can be used to receive realistic predictions regarding concentration and distribution of these defects in Czochralski grown silicon ingots. These capabilities make the software applicable for the process improvement.
Right: The difference between vacancy and interstitial concentrations shows the type of dominating defects and the position of Oxidation-induced stacking fault ring (OSF ring)
Modeling of COP and BMD clusters in Cz Si
Cz Dynamics is a component of CGSim package designed for transient modeling of silicon crystal growth process with changing crystal pulling rate. The tool incorporates automatic algorithm of heater power adjustment to follow user-defined crystal pulling rate profile. Within Cz Dynamics, it is possible to analyze such complex phenomena as the effect of the crystal pulling rate recipe on the melt/crystal interface and defects evolutions during the transitions from the crown to body and from the body to tail. The simulation results include the distribution of vacancy clusters (COP), interstitial clusters (dislocation loops), oxygen clusters (BMD), as well as location of OSF ring in the crystal taking into account nitrogen doping.
Right: COP (two picture on the left) and BMD (two pictures on the right) size and concentration distribution at different moments of silicon growth process. Each image shows the cluster size on the left and cluster density on the right. Crystal diameter is 215 mm (8″), crystal body length is 800 mm (31″) and 1300 mm (51″) respectively.
“Unsteady numerical simulations considering effects of thermal stress and heavy doping on the behavior of intrinsic point defects in large-diameter Si crystal growing by Czochralski method” by Yuji Mukaiyama, Koji Sueoka, Susumu Maeda, Masaya Iizuka, Vasif. M. Mamedov, Journal of Crystal Growth 532 (2020) 125433, https://doi.org/10.1016/j.jcrysgro.2019.125433
“Numerical Modeling of Effect of Thermal Stress and Heavy Doping for Behavior of Intrinsic Point Defects in Si Crystal Growing by Czochralski method” by Y. Mukaiyama, K. Sueoka, S. Maeda, M. Iizuka, and V. M. Mamedov, Proceedings of SISPAD, Kobe, Japan, 2020
“Numerical analysis of effect of thermal stress depending on pulling rate on behavior of intrinsic point defects in large-diameter Si crystal grown by Czochralski method” by Yuji Mukaiyama, Koji Sueoka, Susumu Maeda, Masaya Iizuka, Vasif M. Mamedov, Journal of Crystal Growth 531 (2020) 125334, https://doi.org/10.1016/j.jcrysgro.2019.125334
“Computer Simulation of Concentration Distribution of Intrinsic Point Defect Valid for All Pulling Conditions in Large-Diameter Czochralski Si Crystal Growth” by Koji Sueoka, Yuji Mukaiyama, Susumu Maeda, Masaya Iizuka, Vasif. M. Mamedov, ECS Journal of Solid State Science and Technology, Volume 8, Number 4, https://doi.org/10.1149/2.0011904jss
“Unsteady Numerical Simulation Considering Thermal Stress and Heavy Doping on Behavior of Intrinsic Point Defects in Large-Diameter Si Crystal Growing by Czochralski Method” by Y. Mukaiyama, K. Sueoka, S. Maeda, M. Iizuka and V. M. Mamedov, Proceedings of ICCGE-19, Keystone, Colorado, USA, 2019
“Numerical study of microdefect formation during Cz growth of monocrystalline silicon” by Vasif Mamedov, Vladimir Kalaev, Proceedings of ICCGE-18, Nagoya, Japan, 2016