Effect of O2 plasma surface treatment on gate leakage current in AlGaN/GaN HEMT

This study used O-2 plasma descum pretreatment to investigate the physical and electrical properties of the surface of AlGaN/GaN high electronmobility transistor (HEMT) devices. After O-2 plasma surface treatment on AlGaN/GaN HEMT, the gate leakage current (IG) of 10-8 mA/mm which was less than the untreated IG of 10-6 mA/mm at VG=-6 V. Compared to the device without O-2 plasma treatment, the IG was significantly improved by two orders of magnitude. Two physical mechanisms were discovered. First, surface organic chemical residues were effectively removed (AFM inspection results in a 50% reduction in surface roughness). Second, according to the XPS results, this was the surface passivation caused by Ga-O bond formation. In this work, we discuss the relationship between gate control quality and leakage current, as well as O-2 plasma surface treatment (to create Ga-O bonding). This will show a detailed examination of the gate leakage current. Investigate how O-2 plasma affects the device surface and chemical reactions that cause bonding.