The effect of high-temperature annealing of undoped AlGaN/GaN heterostructures on different substrates was systematically studied between 1100°C and 1230°C. An AlN spacer layer was found to add stability to structures on sapphire substrates. AlGaN/GaN heterostructures on SiC substrates demonstrated excellent robustness for the temperature range studied, maintaining their mobility, sheet resistance, and sheet concentration values, even after annealing. A silicon nitride, SiN x, capping layer was found to assist in minimizing surface roughness during annealing and maintaining the electrical characteristics of the heterostructures. AlGaN/GaN heterostructures on SiC substrates showed a 20% decrease in mobility for uncapped samples compared with SiN x -capped samples.
- Temperature annealing
- sheet resistance
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry