Enhancing Analytical Accuracy of Active Epilayers in Compound Semiconductors by Multi-ion Species Plasma-FIB and Novel STEM Techniques

A novel workflow for analysis of a GaN device is demonstrated by combining state-of-the-art lamella preparation and (S)TEM analysis. Lamella sample preparation using a combination of noble ion sources is used to minimize damage and contamination, enabling accurate epi-layer characterization, chemical analysis, and electric field mapping via (S)TEM. A pristine lamella was prepared from an aluminum gallium nitride (AlGaN/GaN) on sapphire epitaxial stack by switching between ion sources, namely xenon and argon plasma ions, rather than a traditional Ga-FIB system. Subsequent analysis in (S)TEM enabled the examination of electrical behavior, atomic-scale chemical mapping, lattice-resolved interface imaging, and strain and grain orientation analysis. This innovative workflow demonstrates significant potential in enhancing the analytical accuracy for the compound semiconductor industry by allowing the identification of structural and material defects and quality variations at sub-nanoscale dimensions, thereby decreasing learning cycle time.