New nitride chemistries with unique functionalities
The pursuit of sustainable, high-performance nitride semiconductors with unique functionalities (e.g., ferroelectricity) has driven exploration beyond AlGaN and AlScN, limited by scandium’s scarcity, cost, and high-temperature growth incompatibility with silicon BEOL processes. Emerging group-III alloys such as AlYN and AlLaN offer earth-abudant alternatives with enhacned piezoelectric coefficients and wurtzite-phase stability, yet conventional MBE and MOCVD methods face challenges in scalability, impurity control, and thermal budgets. High-vacuum sputtering enables low-temperature, epitaxial growth of AlYN and AlLaN with precise stoichiometry and minimal defects.
By expanding nitride chemistries with refined sputtering methodologies, the Casamento group aims to bridge the gap between theoretical predictions and experimental realization, delivering materials that surpass AlScN in performance, cost, and integration versatility. The development of AlYN and AlLaN heterostructures via high-vacuum sputtering not only advances the frontiers of nitride semiconductors but also paves the way for applications in 6G communications, energy-efficient computing, and resilient power electronics.
Low-temperature growth of high-K dielectrics
The demand for high-K dielectrics capable of withstanding extreme electric fields while enabling miniaturization in advanced electronics has intensified with the rise of high-power, high-frequency, and radiation-hardened applications. Plasma-enhanced approch of ALD (PEALD) enables conformal, low-temperature growth of high-k dielectrics with sub-nanomter thickness control. The plasma-assisted approach leverages reactive nitrogen species to enhance precursor dissociation and surface reactions, minimizing carbon contamination and ensuring precise stoichiometry.
Reference
[1] D Wang et al. Appl. Phys. Lett. 124, 150501 (2024)
[2] J Casamento et al. Appl. Phys. Lett. 124, 142101 (2024)
[3] Applied Physics Letters 124, no. 8 (2024).