Ti/Au/Al/Ni/Au low contact resistance and sharp edge acuity for highly scalable AlGaN/GaN HEMTs

摘要： In this letter, we have reported a novel metal scheme Ti/Au/Al/Ni/Au for ohmic contact on AlGaN/GaN high electron mobility transistors (HEMTs). The reported metal scheme is observed to show minimum metal out-diffusion and sharp edge acuity at high temperature annealing, which facilitates aggressive scaling of source drain separation (LSD). We have demonstrated LSD as low as 300 nm with gate length (Lg) of 100 nm for this metal stack. We observed improvement in ON-Resistance (RON) from 3 ?.mm to 1.25 ?.mm, transconductance (gm) from 276 mS/mm to 365 mS/mm, saturation drain current (IDS,sat) from 906 mA/mm to 1230 mA/mm and unity current gain frequency (fT) from 70 GHz to 93 GHz by scaling LSD from 3 μm to 300 nm. The gate length for all devices were 100 nm.