Reduction of current collapse in AlGaN/GaN MISHEMT with bilayer SiN/Al2O3 dielectric gate stack

• Main Authors: Anand, M. J., Ng, G. I., Vicknesh, S., Arulkumaran, Subramaniam, Ranjan, K.
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electric power
• Online Access: https://hdl.handle.net/10356/100484; http://hdl.handle.net/10220/24127
• Institution: Nanyang Technological University

We have studied the drain current dispersion characteristics of conventional AlGaN/GaN HEMTs and SiN/Al2O3/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MISHEMT) fabricated on silicon substrate. The fabricated MISHEMT exhibited an IDmaxof >1000 mA/mm and gmmax of 241 mS/mm. Compared to conventional AlGaN/GaN HEMTs, about an order of magnitude lower gate leakage current and a ∼ 60% reduction in drain current (ID) collapse was observed in the MISHEMTs. The observation of low ID collapse is due to the occurrence of low interface state density (6.39 × 1010 eV-1 cm-2) between the bilayer dielectric (SiN/Al2O3) and GaN surface which is confirmed through the AC-conductance method.