Al2O3-Passivated Graded-Barrier AlxGa1-xN/AlN/GaN/Si Heterostructure Field-Effect Transistor by Hydrogen Peroxide Oxidization Method

• Published in: ECS journal of solid state science and technology 2017-01, Vol.6 (12), p.Q166-Q170
• Main Authors: Lee, Ching-Sung, Hsu, Wei-Chou, Liu, Han-Yin, Yang, Shen-Ting
• Format: Article
• Language: English
• ISSN: 2162-8769
• DOI: 10.1149/2.0341712jss

This letter reports a novel Al2O3-passivated graded-barrier (GB) AlxGa1-xN/AlN/GaN/Si heterostructure field-effect transistor (HFET) formed by using hydrogen peroxide (H2O2) oxidization method. Different from the Al0.26Ga0.74N conventional barrier (CB), a compositionally graded AlxGa1-xN (x = 0.22∼0.3) barrier was devised to increase the Schottky-barrier height (ΦB) and improve the interfacial quality at the same time. Reduced gate leakage and enhanced device gain are further achieved by the Al2O3 passivation. The present Al2O3-passivated/unpassivated GB-HFETs (unpassivated CB-HFET) has demonstrated improved maximum drain-source current density (IDS, max) of 708/699 (654) mA/mm at VDS = 7 V, maximum extrinsic transconductance (gm, max) of 139/126 (113) mS/mm, subthreshold swing (SS) of 176/253 (274) mV/dec, on/off-current ratio (Ion/Ioff) of 3.8 × 106/1.4 × 104 (7.1 × 103), two-terminal off-state gate-drain breakdown voltage (BVGD) of −126.4/−96.8 (−89.3) V, turn-on voltage (Von) of 1.1/0.7 (0.3) V, and three-terminal on-state drain-source breakdown voltage (BVDS) of 109/89 (71) V.