High Temperature Performance and Low Frequency Noise Characteristics of AlGaN/GaN/AlGaN Double Heterostructure Metal-Oxide-Semiconductor Heterostructure Field-Effect-Transistors with Photochemical Vapor Deposition SiO2 Layer

Abstract

High quality SiO2 films were successfully deposited onto AlGaN using photochemical vapor deposition (photo-CVD). The interface state density, Dit, of photo-CVD SiO2 was estimated to be only 1.1×1011 cm-2eV-1 at room temperature and still only 3.5×1012 cm-2eV-1 even at 175°C. With a 1 µm gate length, it was found that the maximum saturated drain-source current (Ids), maximum transconductance (gm) and gate voltage swing (GVS) of the AlGaN/GaN/AlGaN double heterostructure metal-oxide-semiconductor heterostructure field-effect-transistors (MOS-HFETs) fabricated were 755 mA/mm, 95 mS/mm and 8 V, respectively. Even at 300°C, the maximum saturated Ids and maximum gm of the MOS-HFETs fabricated were still kept at 527 mA/mm and 77 mS/mm, respectively. Furthermore, from the low frequency noise power spectrum, it was found that noise power density of the AlGaN/GaN/AlGaN double heterostructure was lower and presented pure 1/f noise with smaller trapping effects than conventional structures.