Cubic-Structured $\hbox {HfO}_{2}$ With Optimized Doping of Lanthanum for Higher Dielectric Constant

It is demonstrated that HfO₂ films can have much higher dielectric-constant values than the usual reported value of 20-24 by optimized incorporation of lanthanum element and crystallization to cubic structure. When HfO₂ with 8% La is crystallized into cubic structure, the film exhibits the kappa value of ~38 which is the highest among ever reported HfO₂ -based high-kappa dielectrics. The increased kappa value of HfO₂ with 8% La enables the leakage current to be reduced more than one order of magnitude lower, compared to amorphous-phase HfO₂ under the same electric field. The dependence of film thickness and annealing temperature on the cubic crystallization is also reported.