Electron gas dimensionality engineering in AIGaN/GaN high electron mobility transistors using polarization

摘要

We propose and demonstrate a two dimensional/three dimensional hybrid channel AIGaN/GaN high electron mobility transistor (HEMT) structure with a flat transconductance profile using polarization-induced channel engineering. A quasi three dimensional electron gas profile with 5-6 nm of vertical channel depth was formed by grading the channel region linearly from GaN to A1_(0.15)Ga_(0.85)N over 50 AE. We demonstrate a flat g_m profile in an AIGaN/GaN HEMT with high current density of 1 A/mm and peak g_m of 168 mS/mm over 85% of the input bias range under dc conditions. This approach simultaneously enables vertical device scaling and transconductance engineering in a HEMT structure.