Atom Probe Framework Tracks Phase Instability in Si-Doped Gallium Oxide (SUNY, Ohio State, LLNL)
Researchers from SUNY Polytechnic Institute, The Ohio State University, and Lawrence Livermore National Laboratory (LLNL) have developed an atom probe tomography (APT) framework to track phase instability in silicon-doped gallium oxide (Ga₂O₃), a promising ultra-wide-bandgap semiconductor for next-generation power electronics.
As of 2026, gallium oxide is increasingly pursued for high-voltage and high-temperature applications due to its superior breakdown field strength. However, achieving reliable device performance requires precise doping control—particularly with silicon, the most common n-type dopant in Ga₂O₃. Doping-induced local phase changes can introduce defects that degrade material stability and device lifetime.
Using atom probe tomography, the team directly visualized and quantified silicon segregation and precipitation at the nanometer scale. They observed that above a critical doping concentration (approximately 5 × 10¹⁹ cm⁻³), silicon atoms begin to cluster and form secondary phases, initiating structural instability. This clustering was linked to local lattice strain and the formation of β-Ga₂O₃ polymorph variants in otherwise homogeneous material.
The framework integrates experimental APT data with density functional theory (DFT) calculations to predict the onset of phase instability as a function of doping concentration and processing conditions. This combined approach provides a predictive tool for optimizing doping strategies in Ga₂O₃, enabling manufacturers to avoid detrimental phase separation while maximizing carrier concentration.
These findings have direct implications for the design of Ga₂O₃-based transistors, Schottky diodes, and other power devices. By establishing a quantitative threshold for stable silicon doping, the work accelerates the development of more reliable, high-performance Ga-oxide electronics.
The study represents a collaboration across materials science, computational physics, and semiconductor engineering, highlighting the value of atomic-scale characterization in refining doping processes for emerging wide-bandgap semiconductors.