Influence of Physical Parameters on Microwave Noise Characteristics of Al0.3Ga0.7N/Al0.05Ga0.95N/GaN Composite-Channel HEMTs

Abstract

THE Al0.3Ga0.7N/Al0.05Ga0.95N/GaN CC-HEMT structure is shown in [12]. It consists of 2 µm sapphire substrates, a 2.5 µm GaN undoped minor channel layer, a 6 nm Al0.05Ga0.95N undoped major channel layer, a 3 nm Al0.3Ga0.7N undoped spacer layer, a 21 nm doped(1e18) carrier supplier layer and a 2nm undoped cap layer. The devices have a source-gate spacing of Lsg=0.5 µm, gate-drain spacing of Lgd=1 µm, a 1 µm -gate-length and a gate width of 1 µm [12]. The band gap (Eg), affinity and electron mobility of layers of this device are shown in Table I. The polarization charge density at the interface of Al0.3Ga0.7N/Al0.05Ga0.95N and Al0.05Ga0.95N/GaN is calculated. The polarization charge density is 1.12e13 cm -2