Designing CMOS-compatible OTS materials for next-gen memory devices: density functional theory insights on switching mechanisms.

The microelectronics industry is approaching the limits of Moore’s law, which has traditionally driven device miniaturization. To continue advancing energy efficiency and performance —particularly in memory technologies — new physical principles, materials, and device architectures must be explored beyond conventional downscaling. In this context, emerging memory concepts such as selector-only memory are gaining attention. However, current Ovonic Threshold Switching (OTS) materials pose integration challenges within standard CMOS process flows. Therefore, identifying and developing CMOS-compatible materials that exhibit similar OTS behaviour is essential for scalable design.

Advancing existing technologies and shaping the medium- to long-term vision for future microelectronic devices requires a deep understanding of the theoretical limits, properties, and interactions of the constituent materials. These materials often exhibit complex behaviours, including defect dynamics, interfacial interactions (e.g., interfacial dipoles, effective work function shifts, atomic segregation effects), and time-dependent morphological changes such as phase transitions and threshold switching. A comprehensive understanding of these phenomena is critical for reliable device design and integration.

In this Ph.D. project, we aim to design and explore new CMOS-compatible materials for Ovonic Threshold Switching (OTS) memory by leveraging first-principles simulations for investigating thin films, interfaces with metallic electrodes, electronic transport properties, and the role of defects. Developing a fundamental understanding of material properties is essential for establishing a robust theoretical framework for assessing performance and reliability—this forms the backbone of the Ph.D. research.

Throughout the project, the Ph.D. student will conduct state-of-the-art ab initio calculations. Successfully executing these simulations requires a solid grasp of the underlying theoretical principles, as well as familiarity with their implementation in computational codes optimized for high-performance computing environments. Moreover, the simulations demand a nuanced understanding of the relevant chemistry, particularly in relation to bonding, oxidation states, and phase stability, to accurately model and interpret the behaviour of candidate materials.

Eligibility criteria: Master’s degree in physics or chemistry (focusing on theoretical aspects). Due to the complexity and the high amount of individual calculations, an efficient and robust automation and data processing infrastructure is essential. A strong motivation, good knowledge of solid-state physics or quantum chemistry and UNIX/LINUX are a plus. Writing / oral communication skills are required.