Textured crystallization of ultrathin hafnium oxide films on silicon substrate

The effects of rapid thermal annealing are reported here on the structure of 2 nm thick hafnium oxide films grown on silicon (100) substrates. The films grown by atomic layer deposition have a 1 nm SiO₂ transition layer between silicon and the HfO₂ layer. The amorphous structure of the as-deposited films is retained after annealing at 600 °C. The HfO ₂ films crystallized into an orthorhombic phase with an out-of-plane texture after annealing at 800 °C or higher. In contrast, films grown on thick amorphous SiO₂ substrates crystallize without any texture. The authors attribute the texture of HfO₂ on Si (100) to the role of interfacial SiO₂ transition layer.