Atomic Insight for Regulation of Thermal Boundary Resistance Between Silicon and AlN via Machine Learning Potential

Three-dimensional integrated circuits (3D ICs) have become a cornerstone of next-generation electronic devices, offering exceptional density and performance. However, their stacked architecture poses a significant challenge for heat dissipation, leading to thermal accumulation. The inherent Joule self-heating effect further exacerbates this issue, potentially reducing device efficiency and lifespan. In these silicon-based devices, SiO2 is commonly used as an insulator, but its low thermal conductivity limits effective heat management. Consequently, from a thermal dissipation perspective, a high-thermal-conductivity insulator compatible with silicon processing is highly desirable, and aluminum nitride (AlN) stands out as a promising candidate. In this research, we explore the use of AlN to partially replace low-thermal conductivity SiO2 in Si-based advanced semiconductor devices with 3D integrated circuits. To investigate the thermal transport characteristics at Si-AlN interfaces, the machine learning potential (MLP) for Si-AlGaN is first established, and the TBR of Si-AlN and Si-amorphous AlGaN samples are evaluated by both molecular dynamic (MD) simulation and time-domain thermoreflectance (TDTR) measurement. The interfacial atomic ordering is changed by introducing AlGaN interlayers, to observe the impact of these changes on thermal transport, scanning transmission electron microscopy (STEM) is employed to examine the Si-AlN/AlGaN-AlN interface. From the atomic level, the density of states (DOS) analysis and phonon transmission coefficient are utilized to explain the impact of various interface configurations on thermal transport. In addition, phonon wave packet simulations further revealed the influence of atomic ordering at the interface on phonon transport.
This work provides valuable insights into understanding the interfacial thermal transport between silicon and nitride semiconductors and useful guidance for thermal management via interface engineering.