Influence of barrier and spacer layer on structural and electrical properties of AlGaN/GaN HEMT

摘要

A systematic numerical simulation of AlGaN/ GaN-based HEMT is performed to demonstrate a strong dependence between the thickness and content of Al in the barrier layer on the electrical characteristics of HEMT. The impact of introducing a thin A1N spacer layer is also studied. A high mobility of 1901.2 cm~2/Vs and an electron concentration of 3.036 × 10~(13) cm-2 is achieved by adding an A1N spacer in the standard AlGaN/GaN HEMT having barrier thickness as 27 nm and Al composition of 25%, while electron mobility and electron density of 1767 cm2/ Vs and 2.778 × 10~(13) cm~(-2), respectively, is achieved for a standard optimized AlGaN/GaN structure. It is further presented that optimization of HEMT structure using numerical simulation tools is an efficient method of improving the electrical properties of the transistor structure preceding the fabrication of the device.