Post-growth surface engineering of AlGaN via Mn thermal diffusion for contact applications

A post-growth approach for electronic properties engineering of AlGaN layers through thermally stimulated Mn diffusion has been investigated. This method relies on maintaining AlGaN at elevated temperature under an Mn flux. Structural and chemical analyses reveal the incorporation of Mn atoms into the subsurface region, which impact its electronic properties. This diffusion-driven modification of the AlGaN subsurface region results in changes to the valence band structure and thus changes in electrical characteristics of the interconnection of modified layer with metallic contact. The pronounced transition in the I-V characteristics from Schottky-type to ohmic-like behavior demonstrates that thermally driven Mn diffusion is an effective post-growth technique for tuning the electrical properties of AlGaN layers.