Effects of SF6 plasma treatment on electrical characteristics of TaN-Al2O3-InP metal-oxide-semiconductor field-effect transistor

Abstract

The effects of SF6 plasma treatment of Al2O3 on InP substrate have been investigated in this paper. Electrical characteristics including drive current, effective channel mobility, transconductance, subthreshold swings, etc., have been compared for devices with SF6 plasma treatment at different power (P = 30 or 50 W) for different time (t = 3, 5, or 7 min). With 5 min SF6 plasma treatment at power = 30 W, the maximum drive current is increased by 20% to 60.2 μA/μm and effective channel mobility is increased by 36.7% to 1099 cm2/V s for devices on InP substrate with 7 nm Al2O3 (EOT ∼ 3.4 nm and W/L = 600 μm/10 μm). It is believed S and F atoms are incorporated into Al2O3 bulk and Al2O3/InP interface, so that better oxide quality and a lower interface trap density are achieved by SF6 plasma treatment at optimal power with optimal time duration.