Impact of GaN channel scaling in InAlN/GaN HEMTs

This paper studies the impact of GaN channel thickness scaling on the DC and RF performance of InAlN/GaN high electron mobility transistors (HEMTs) with 30-230 nm gate length. Thin GaN channels increase the charge confinement, which improves immunity to short-channel effects. However, as the channel thickness scales down, mobility degradation is observed due to additional interface and alloy scattering caused by the InGaN back barrier layer. Due to this higher interface scattering, the effective electron velocity decreases when thinning down the channel from 26 nm (v_e=1.45 × 10⁷ cm/s) down to 4 nm (v_e=1.16 × 10⁷ cm/s).