Textured Crystallization of Ultrathin Hafnium Oxide Films on Silicon Substrate

Fakhruddin Bohra, University of Illinois at Urbana-Champaign
Bin Jiang, Portland State University
Jian-Min Zuo, University of Illinois at Urbana-Champaign

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Abstract

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 HfO₂ 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.