Aspects of Epitaxial Design and Estimation of 2DEG Mobility in InAlN/AlN/InGaN/GaN High Electron Mobility Transistors

In this paper, a epitaxial design of InAlN/AlN/InGaN/GaN high electron mobility transistors (HEMTs), considering the vital aspects related to its device exploration is proposed. Mobility of two dimensional electron gas in the proposed, practically viable structures of In_xGa_1−xN‐channel (0.1 < x < 0.4) HEMT is estimated. It is shown that 2DEG mobility is predominantly limited by alloy scattering rather than phonon scattering, unlike in conventional GaN‐channel HEMTs. Finally, room temperature mobility of 2DEG in InGaN‐channel HEMT is simulated on the basis of alloy scattering and phonon scattering only. Results are in close proximity with reported experimental results. We observe that, for n_s≈ 2 × 10¹³ cm⁻², mobility drops rapidly from ≈900 to ≈550 cm² V⁻¹ · s⁻¹as ‘x’ is increased from 0.1 to 0.2 and thereafter it decreases at a relatively lesser rate. Severe degradation in mobility is predicted for x > 0.3.