Effect of AlN Interlayer Thickness on 2DEG Parameters in AlGaN/AlN/GaN HEMT Structures

This study aims to determine the relationship between the thickness of the AIN interlayer and the mobility and concentration of 2DEG in AIGaN/AIN/GaN HEMT structures. The results indicate that the thickness of the AIN interlayer has a significant effect on the 2DEG parameters in AIGaN/AIN/GaN HEMT structures. The electrophysical parameters of 2DEG were measured for AIN interlayer thicknesses ranging from 0 nm to 1.5 nm. The dependence of the 2DEG parameters on the thickness of the AIN interlayer allows control of the electron gas characteristics based on the transistor requirements. After determining the effect of AIN interlayer thickness in AIGaN/AlN/GaN structures on sapphire substrates, similar structures with AIN interlayer thicknesses of 1.0 and 1.5 nm were grown on SiC substrates with 2DEG electrophysical parameters: $\mu=1860 \mathrm{~cm}^{2} \mathrm{~V}^{-1} \mathrm{~s}^{-1}$ and $\mathrm{n}=1.06 \times 10^{13} \mathrm{~cm}^{-2}$, and $\mu=1310 \quad \mathrm{~cm}^{2} \mathrm{~V}^{-1} \mathrm{~s}^{-1}$ and $\mathrm{n}=2.0 \times 10^{13} \mathrm{~cm}^{-2}$, respectively. The obtained mobility and concentration parameters of 2DEG were compared with world-class results and showed a correlation.