Oxide defects of Laser-spike-annealed ultrathin Hafnium-oxide High-k dielectric stacks

We studied the effect of laser spike annealing (LSA) on the defects of hafniumoxide (HfO ₂) high-k dielectric stacks. We found that positive charge generation, extracted from C-V measurements was suppressed for laser spike annealed HfO ₂ gate stacks compared with conventional rapidthermally-annealed (RTA) gate stacks. It seems that LSA suppresses the growth of under-oxidized interfacial oxide layer by minimizing oxygen diffusion, 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 HfO ₂ gate stacks. High-density non-equilibrium chargetrapping defects seem to be created in the HfO ₂ 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 effectively deactivate the LSAcreated oxide defects.