Fully Vertical GaN p-i-n Diodes Using GaN-on-Si Epilayers

Using GaN-on-Si epilayers, for the first time, fully vertical p-i-n diodes are demonstrated after Si substrate removal, transfer, and n-electrode formation at the top of the device. After SiO
₂
sidewall passivation, the vertical p-i-n diodes, with n-GaN facing up, exhibit VON of 3.35 V at 1 A/cm
²
, a low differential ON-resistance of 3.3 mΩcm
²
at 300 A/cm
²
, and a breakdown voltage of 350 V. The corresponding Baliga's figure of merit is 37.0 MW/cm
²
, a very good value for GaN-based p-i-n rectifiers grown on Si substrates. The results indicate that fully vertical rectifiers using GaN-on-Si epilayers have great potential in achieving cost-effective GaN devices for high-power and high-voltage applications.