Virtual Reactor: A New Tool for SiC Bulk Crystal Growth Study and Optimization

Development of 2" AlN Substrates Using SiC Seeds

“…The model was validated in (Segal et al, 2000) by the comparison with the experimental data on the AlN growth rate as a function of the temperature and the pressure; it is implemented as software package Virtual Reactor TM (Bogdanov et al, 2001;STR-soft, 2000). Virtual Reactor TM provides an accurate simulation of all major physical-chemical phenomena relevant to this method such as resistive or RF heating ; conductive, convective and radiative heat transfer; mass transfer in gas and porous media; heterogeneous chemical reactions at the catalytic walls and on the surface of powder granules; deposits formation; formation of elastic strain and dislocations in the growing crystal; the evolution of the crystal and of the deposit shape, including partial facetting of the crystal surface.…”

Industrial Challenges for Numerical Simulation of Crystal Growth

“…There are reasons for that: a great number of available commercial and public-domain generic CFD codes [7]; cheap high power hardware; industry's reluctance to reveal proprietary information to outside consulting partners; in-house operation allows to use simulation routinely in everyday work. Industry needs customized multidisciplinary simulators that hide from the user intricacies of numerical issues and allow the engineer to concentrate on her/his problem [4,6,13,29,36]. There are two approaches to development of such growth simulators.…”

“…In the sublimation method a single crystal is grown from the vapour phase in a closed crucible, the transport being provided by a suitable temperature gradient between the powder charge and the seed. The code "Virtual Reactor" (VR) [4] for crystal growth by sublimation has been developed as a tool for industry engineers. It provides an accurate solution of all major physical-chemical phenomena relevant to this method such as resistive or RF heating ; conductive, convective and radiative heat transfer; mass transfer in gas and porous media; heterogeneous chemical reaction at catalytic walls and on the surface of powder granules; deposits formation; formation of elastic strain and dislocations in the growing crystal; evolution of crystal and deposit shape.…”

“…A few known examples of process optimization use a small number of control parameters (such as heater(s) power/position in Cz growth [29] or mass flow rates and susceptor rotation rate in CVD [12]) and thus probably does not encounter ill-posedness of the inverse problems to be solved. When the number of control parameters is large, one is forced to use a regularization of some kind [38] as in the optimization of the crucible design for SiC bulk crystal growth [4]. Probably the most advanced example of the crystal growth optimization is an application of the adjoint method to the solution of the inverse problem for the optimal boundary heat flux distribution in the directional solidification and Bridgman method [45].…”

Industrial challenges for numerical simulation of crystal growth

“…One can either track it explicitly or use one of the 'uniform' methods such as the enthalpy model [35], the level set approach [56], the phase-¯eld model [5,66]. In the latter, for example, solid phase is considered as a°uid with a very large viscosity [1].…”