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

This study used O
2
plasma descum pre-treatment to investigate the physical and electrical properties of the surface of AlGaN/GaN high electron-mobility transistor (HEMT) devices. After O
2
plasma surface treatment on AlGaN/GaN HEMT, the gate leakage current (I
G
) of 10
⁻⁸
mA/mm which was less than the untreated I
G
of 10
⁻⁶
mA/mm at
$\mathrm{V}_{\mathrm{G}}=-6\ \mathrm{V}$
. Compared to the device without O
2
plasma treatment, the I
G
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.