Researchers from Stony Brook University’s Department of Materials Science and Chemical Engineering have mapped out the atomic-scale mechanisms that dictate how silicon carbide (SiC) thin films grow. This will help pave the way for next-generation, high-efficiency wide-bandgap semiconductors.
The study, conducted at the onsemi Research Center for Wide Bandgap Materials at Stony Brook University, was featured on the cover of the Journal of Applied Physics (Vol. 139, Art. 245302) and highlighted as an “Editors’ Pick.”
Kevin Kayang, a postdoc, led the paper entitled, “Mechanisms of nucleation, dislocation formation, and stress evolution during atomistic growth of SiC films on miscut 4H-SiC substrates,” with Professor Dilip Gersappe as the corresponding author and Professors Michael Dudley and Balaji Raghothamachar contributing as co-authors.
SiC is a highly sought-after semiconductor material used in heavy-duty, high-powered applications. These include electric vehicles (automotive systems), energy storage, semiconductor diodes, power transistors and potentially quantum computing.
It is highly coveted because of its four properties: 1) a wide bandgap energy which reduces leakage currents at high temperatures; 2) superior thermal conductivity which dissipates heat effectively; 3) a high breakdown electric field which allows the semiconductor to withstand massive voltages without breaking down; and 4) high saturated electron field drift velocities which enable electrons to move through material at faster maximum speeds.
For decades, monitoring or controlling defect formation in SiC crystals in real-time has remained an immense experimental challenge. This is because SiC crystals are traditionally grown in a specialized, high-temperature container that is almost closed and made of graphite. They are grown at temperatures ranging from 2300 K to 2800 K, comparable to those found in systems such as advanced nuclear reactors or aerospace thermal protection systems.
To overcome this limitation, the Stony Brook team turned to high-fidelity computational modeling. By employing state-of-the-art molecular dynamics (MD) simulations, they successfully observed and analyzed the vapor-phase deposition and layer-by-layer growth of SiC films across a variety of temperatures and alignment conditions.
Dudley said, “Our team’s simulations revealed critical insights into how substrate temperature and ‘miscut angles’ — the intentional tilt angle of the underlying crystal substrate — control the structural quality and defects of the growing film.”
He explained that by revealing the precise physical parameters at the atomic scale, “our work provides a vital blueprint to optimize low-defect SiC film growth.”
Gersappe added, “Minimizing structural defects and residual stress is essential to unlocking the full device performance capabilities of 4H-SiC films in commercial electronics and wide-bandgap applications.”
This high-impact research was supported by the onsemi Research Center for Wide Bandgap Materials at Stony Brook University and funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy. High-performance computing resources were provided by the Institute for Advanced Computational Science (IACS) at Stony Brook University via the SeaWulf system, funded by the National Science Foundation and NYSTAR.
— Debra Scala Giokas
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