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 degrees C. The HfO2 films crystallized into an orthorhombic phase with an out-of-plane texture after annealing at 800 degrees 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. (c) 2007 American Institute of Physics.