Effect of O₂plasma surface treatment on gate leakage current in AlGaN/GaN HEMT

This study used O2 plasma descum pre-treatment to investigate the physical and electrical properties of the surface of AlGaN/GaN high electron-mobility transistor (HEMT) devices. After O2 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 O2 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 O2 plasma surface treatment (to create Ga-O bonding). This will show a detailed examination of the gate leakage current. Investigate how O2 plasma affects the device surface and chemical reactions that cause bonding.