Oxide Defects of Laser-Spike-Annealed Ultrathin Hafnium-Oxide High-k Dielectric Stacks

We studied the e ect of laser spike annealing (LSA) on the defects of hafniumoxide (HfO2) high-k dielectric stacks. We found that positive charge generation, extracted from C-V measurements was suppressed for laserspikeannealed HfO2 gate stacks compared with conventional rapidthermallyannealed (RTA) gate stacks. It seems that LSA suppresses the growth of under-oxidized interfacial oxide layer by minimizing oxygen di usion, resulting in less positive charge generation. C-V hysteresis and defect photoluminescence, however, showed enhanced charge trapping and increased oxide defect density for the laser spike annealed HfO2 gate stacks. High-density non-equilibrium chargetrapping defects seem to be created in the HfO2 layer during the rapid cooling process of LSA. We performed post-LSA, lowthermalbudget annealings in various ambient gases to quench or passivate chargetrapping defects, but they didn't seem to e ectively deactivate the LSAcreated oxide defects.