On the Understanding of Cathode Related Trapping Effects in GaN-on-Si Schottky Diodes

Cathode related current collapse effect in GaN on Si Schottky barrier diodes is investigated in this paper. Capacitance and current relaxation measurements on diodes and gated-Van Der Pauw are associated with temperature dependent dynamic RON transients analysis to identify the parasitic trapping locations in the devices. We show here that the main part of the current collapse at the cathode comes from a combination of electron trapping in the passivation layer and in a carbon related trap in the GaN buffer layers (E A = E T - E V ≃ 0.9 eV) that can be studied independently by using the appropriate stress configurations. These two parasitic effects can lead to long recovery time (>1 ks) after reverse bias stress.