Self-Heating and Bias Temperature Instability in Recessed-Gate GaN MIS-HEMTs with AlN/SiNx Bilayer Dielectric

Self-heating and bias temperature instability (BTI) in E-mode recessed-gate GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMT) were investigated. Thermoreflectance thermography was performed in the recessed-gate GaN MIS-HEMT, revealing a different heat distribution at the gate region and lower channel temperature compared with the D-mode GaN HEMT under the same DC power and drain bias. BTI measurements indicates that V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</inf> shift and R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> degradation are more significant at elevated temperatures, due to the trapping/detrapping process of electrons at the AlN/SiN<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> dielectric layer interface.