Room temperature formation of Hf-silicate layer by pulsed laser deposition with Hf-Si-O ternary reaction control

• Published in: AIP advances Vol. 6; no. 10; pp. 105303 - 105303-7
• Main Authors: Hotta, Yasushi, Ueoka, Satoshi, Yoshida, Haruhiko, Arafune, Koji, Ogura, Atsushi, Satoh, Shin-ichi
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.10.2016; AIP Publishing LLC
• Subjects: Atomic states; Hafnium oxide; High vacuum; Lasers; Organic chemistry; Photoelectric emission; Pulsed laser deposition; Pulsed lasers; Reaction control; Room temperature; Silicon substrates; Stability; Thickness; X ray photoelectron spectroscopy
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4964932

We investigated the room temperature growth of HfO2 layers on Si substrates by pulsed laser deposition under ultra-high vacuum conditions. The laser fluence (LF) during HfO2 layer growth was varied as a growth parameter in the experiments. X-ray photoemission spectroscopy (XPS) was used to observe the interface chemical states of the HfO2/Si samples produced by various LFs. The XPS results indicated that an interface Hf-silicate layer formed, even at room temperature, and that the thickness of this layer increased with increasing pulsed LF. Additionally, Hf-Si bonds were increasingly formed at the interface when the LF was more than 2 J/cm2. This bond formation process was related to decomposition of HfO2 to its atomic states of Hf and O by multiphoton photochemical processes for bandgap excitation of the HfO2 polycrystalline target. However, the Hf-Si bond content of the interface Hf-silicate layer is controllable under high LF conditions. The results presented here represent a practical contribution to the development of room temperature processing of Hf-compound based devices.