Effects Of Pecvd Sio2 Gate Dielectric Thickness On Recessed Algan/Gan Mos-Hfets

We have investigated the interface fixed charge density and the oxide bulk charge density of the metal/PECVD SiO2/recessed GaN MOS structure. The fabricated AlGaN/GaN-on-Si recessed MOS-HFETs exhibited the excellent on/off ratio characteristics. The extracted effective interface fixed charge density and effective oxide bulk charge density for the PECVD SiO2 deposited on the recessed GaN surface were -5.94 x 10(11) cm(-2) and -2.19 x 10(17) cm(-3), respectively. The negative bulk charges in the SiO2 layer were responsible for the positive shift in the threshold voltage as the SiO2 thickness increased.