Enhancement of Ru–Si–O/In–Ga–Zn–O MESFET Performance by Reducing Depletion Region Trap Density

In this letter, we investigated the effect of magnetron cathode current (I
_c
) during reactive sputtering of In-Ga-Zn-O (a-IGZO) channel layer on properties of metal-semiconductor field-effect transistors with Ru-Si-O Schottky gate electrode. One can observe that as I
_c
increased from 90 to 150 mA channel mobility (μ
_ch
) and subthreshold swing (S) improved from μch = 7.5 cm
²
/V·s and S = 580 V/dec to μch = 8.8 cm
²
/V ·s and S = 420 V/dec, respectively. This enhancement in transistors performance was attributed to the reduction of charge density in the depletion region of Ru-Si-O/In-Ga-Zn-O Schottky contacts, which we assigned to the densification of a-IGZO films fabricated at higher I
_c
.