Abstract
Scanning tunneling microscopy is used to study trap evolution in the Sc2O3/La2O3/SiOx gates tack. Current-voltage characteristics extracted from leakage sites exhibit stress-induced-leakage-current (SILC) or barrier-height-lowering (BHL) behavior. The high-κ layer is observed to have larger intrinsic trap generation rate, compared to the SiOx layer, due to a higher surface plasmon generated hot-hole current at the tip/high-κ interface. In the presence of electronic traps: (i) SILC traps near the cathode inhibit trap generation in the layer near the anode due to inelastic-trap-assisted-tunneling mechanism; (ii) SILC traps near the cathode may evolve into BHL as lattice displacement due to electron charging during the inelastic-trap-assisted tunneling process may accelerate the wear-out of the neighboring region; and (iii) traps with BHL characteristics in the high-κ may accelerate the breakdown of the Interfacial layer (IL) due to enhanced electric field in the IL. An electrical stress induced trap evolution model in the gate stack is proposed.
