Citation

Lee JH. Journal of the Korean Physical Society 2004; 44(6): 1590-1593.

Copyright

(Copyright © 2004)

DOI

unavailable

PMID

unavailable

Abstract

The thermal instability and silicidation behaviors of ultrathin HfO x on Si(001) were studied by using scanning tunneling microscopy (STM) with in-situ X-ray photoelectron spectroscopy (XPS). A 1.5-nm-thick HfO x layer was grown on Si(001) by using Hf deposition in an oxidizing ambient. In the low temperature (600 ∼ 800°C) region, hafnium oxide near the interface region easily reacted with the substrate silicon ions in order to form a silicate structure (Hf-O-Si bonding units). When the SiO evaporation proceeded in the high-temperature (≥ 900°C) region, silicon migration from the substrate became kinetically remarkable and transformed the Hf-O-Si units into Hf-Si bonds with some remnant Si-O bonds. In contrast with the multi-phase feature of crystalline HfSi 2 that has been reported to occur by annealing hafnium metal on ultrathin SiO 2, our STM study reveals the formation of "irregularly shaped" suicides upon silicidation. These suicides contain some oxygen in the form of Si-O bonds, so they exhibit a slightly insulating behavior in the spectroscope mode of STM.

Language: en

Keywords

Scanning tunneling microscopy; Gate dielectric; Hafnium oxide