Heat transfer—A review of 2005 literature

The growth of high-purity, semi-insulating (HPSI) 4H-SiC crystals has been achieved using the seeded-sublimation growth technique. These semi-insulating (SI) crystals (2-inch diameter) were produced without the intentional introduction of elemental deep-level dopants, such as vanadium, and wafers cut from these crystals possess room-temperature resistivities greater than 109 Ωcm. Based upon temperature-dependent resistivity measurements, the SI behavior is characterized by several activation energies ranging from 0.9-1.5 eV. Secondary ion mass spectroscopy (SIMS) and electron paramagnetic resonance (EPR) data suggest that the SI behavior originates from deep levels associated with intrinsic point defects. Typical micropipe densities for wafers were between 30 cm-2 and 150 cm-2. The room-temperature thermal conductivity of this material is near the theoretical maximum of 5 W/mK for 4H-SiC, making these wafers suitable for high-power microwave applications.

High-purity semi-insulating 4H-SiC grown by the seeded-sublimation method

https://iopscience.iop.org/article/10.1088/1361-6641/aad831/pdf

Review of SiC crystal growth technology

The productivity and quality of SiC bulk crystal grown from vapor phase depend strongly on the temperature distribution in a SiC growth chamber. An analytical formulation is proposed to correlate the growth rate with process parameters such as pressure, temperature, and temperature gradient. A growth kinetic model is also developed to predict the growth rate and examine the transport effects on the growth rate and dislocation formation. Simulation and analytical results show that the growth rate increases when the growth temperature increases, argon pressure decreases, and/or the temperature gradient between the source and seed increases. An anisotropic thermoelastic stress model is proposed to study the influence of thermal stress on dislocation density. The method to attach the seed is observed to play an important role in stress distribution in an as-grown silicon carbide ingot.

Growth Kinetics and Thermal Stress in the Sublimation Growth of Silicon Carbide

Integrated process modeling and experimental validation of silicon carbide sublimation growth

Modeling of silicon carbide crystal growth by physical vapor transport method

Wide-bandgap silicon carbide (SiC) substrates are needed for fabrication of electronic and optoelectronic devices and circuits that can function under high-temperature, high-power, high-frequency conditions. The bulk growth of SiC single crystal by physical vapor transport (PVT), modified Lely method involves sublimation of a SiC powder charge, mass transfer through an inert gas environment, and condensation on a seed. Temperature distribution in the growth system and growth rate profile on the crystal surface are critical to the quality and size of the grown SiC single crystal. Modeling of SiC growth is considered important for the design of efficient systems and reduction of defect density and micropipes in as-grown crystals. A comprehensive process model for SiC bulk growth has been developed that incorporates the calculations of radio frequency (RF) heating, heat and mass transfer and growth kinetics. The effects of current in the induction coil as well as that of coil position on thermal field and growth rate have been studied in detail. The growth rate has an Arrhenius-type dependence on deposition surface temperature and a linear dependence on the temperature gradient in the growth chamber.

Modeling of Heat Transfer and Kinetics of Physical Vapor Transport Growth of Silicon Carbide Crystals

Kinetics and modeling of sublimation growth of silicon carbide bulk crystal

Modeling of transport processes and kinetics of silicon carbide bulk growth

Silicon carbide (SiC) substrates can be used to fabricate electronic devices and circuits which can function under extreme high-temperature, high-power, high-frequency conditions. The bulk growth of SiC single crystal by physical vapor transport (PVT) technique (modified Lely method) involves sublimation of a SiC powder charge, mass transfer through an inert gas environment, and condensation on a cold substrate seed. The SiC vapor deposits on the seed which has a lower temperature than the powder charge, and the SiC single crystal grows. Control of mass transfer and temperature distribution in the furnace with an extremely high temperature is critical to the quality of grown SiC single crystal. Modeling of the growth process is important for the design of efficient growth furnaces and reduction of micropipes and defect density in the grown crystal. A system model for SiC growth by PVT method is developed here that incorporates the radio frequency (RF) heating, and radiative and conductive heat transfer in the growth system. The generated heat power by RF heating of the graphite susceptor is calculated by solving the electromagnetic field. It is found that the radiation heat transfer plays a dominant role under high temperature and low pressure conditions.

C.M. Balkas

Papers

Modeling of silicon carbide crystal growth by physical vapor transport method

Modeling of Heat Transfer and Kinetics of Physical Vapor Transport Growth of Silicon Carbide Crystals

Kinetics and modeling of sublimation growth of silicon carbide bulk crystal

Modeling of transport processes and kinetics of silicon carbide bulk growth

A system model for silicon carbide crystal growth by physical vapor transport method