Demonstration of AlGaN/GaN MISHEMT on Si with low-temperature epitaxy grown AlN dielectric gate

• Main Authors: Whiteside, Matthew, Arulkumaran, Subramaniam, Dikme, Yilmaz, Sandupatla, Abhinay, Ng, Geok Ing
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Electrical and electronic engineering; LTE; AlN
• Online Access: https://hdl.handle.net/10356/148696
• Institution: Nanyang Technological University

AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMT) with a low-temperature epitaxy (LTE)-grown single crystalline AlN gate dielectric were demonstrated for the first time and the post-gate annealing effects at 400 °C were studied. The as-deposited LTE-AlN MISHEMT showed a maximum drain current (I Dmax) of 708 mA/mm at a gate bias of 4 V and a maximum extrinsic transconductance (g mmax) of 129 mS/mm. The 400 °C annealed MISHEMT exhibited an increase of 15% in g mmax, an order of magnitude reduction in reverse gate leakage and about a 3% suppression of drain current (I D) collapse. The increase of g mmax by post-gate annealing is consistent with the increase of 2DEG mobility. The suppression of I D collapse and the reduction of gate leakage current is attributed to the reduction of interface state density (5.0 × 10¹¹ cm⁻²eV⁻¹) between the AlN/GaN interface after post-gate annealing at 400 °C. This study demonstrates that LTE grown AlN is a promising alternate material as gate dielectric for GaN-based MISHEMT application.