Preparation of epitaxial YSZ thin film deposited on SiO2/Si(001) at room temperature by pulsed laser deposition (PLD)

Abstract

YSZ thin films were deposited by pulsed laser deposition (PLD) on Si (001) with native SiO2, H-terminated Si (001) and ablated Si on H-terminated Si(001) at various temperatures (800, 600, 400, 200°C and RT (room temperature)). The crystallinity of YSZ thin film on Si (001) with native oxide was the highest among the three substrates. YSZ thin film on ablated Si on H-terminated Si (001) was amorphous. We suggest that an ultrathin SiO2 layer (< 1.1 nm) is necessary for crystal growth of YSZ thin film. A two-step process was attempted to prepare epitaxial YSZ thin films. First, YSZ thin films were deposited on Si (001) with native SiO2 at 800°C in 8.0 × 10-5 Pa O2 (reduction condition). Second, YSZ thin films were deposited on Si(001) with native SiO2 at various temperatures (800, 600, 400, 200°C and RT) in 7.3 × 10-2 Pa O2. All YSZ thin films deposited by a two-step process were epitaxial. The reason for this mechanism is discussed.