Molecular dynamics simulations of ultrafast radiation induced melting at metal-semiconductor interfaces

Metal-semiconductor contacts in silicon carbide (SiC) diodes endure damages at the interface when exposed to harsh radiation environments. Due to the rapid rise in temperature and ultrafast cooling that follows the radiation impact, the structural properties of the materials can be altered through melting, recrystallization, and amorphization. A detailed understanding of the material failure modes at the interface is lacking, specifically at the nanoscale. We use molecular simulations to investigate the ultrafast melting at tungsten (W)-SiC interfaces following radiation damage and apply deep learning techniques to track the transient evolution of the local molecular structures. We show that W near the radiation track undergoes melting and, eventually, most of it recrystallizes with a noticeable degree of undercooling, while SiC is rendered permanently amorphous. The observation of local undercooling in W films is important as it can affect the device performance even before the bulk melting temperature of the material is reached. We also show that at high temperatures, the interface undergoes a fracture-like failure. The results presented here are significant in understating the different failure modes of SiC diode materials.

Automated summary

Metal-semiconductor contacts in silicon carbide diodes experience melting, recrystallization, and permanent amorphization at the interface when exposed to harsh radiation environments. Molecular simulations show tungsten near the radiation track undergoes melting, with most of it recrystallizing with noticeable undercooling, while SiC becomes permanently amorphous. Local undercooling in tungsten films can impact device performance before bulk melting temperature is reached, and high temperatures can cause interface fracture-like failure. These findings are crucial for understanding diverse failure modes in SiC diode materials.