LiNbO₃振動子を用いた連続膜形成検知センサの感度評価

抄録

We develop a sensor that uses resonance vibrations of a piezoelectric material for detecting continuous-film formation during deposition, and compare the sensitivity of sensors that use LiNbO₃ and α-quartz resonators; LiNbO₃ has higher piezoelectricity than that of α-quartz. The sensor is placed just below a substrate, and the film is deposited on a top surface of the substrate. Continuous-film formation is detected by monitoring the change in the resonance frequency and internal friction of an oscillator, which is caused by change in the electric conductivity of the deposited film. We locate α-quartz and LiNbO₃ oscillators below a substrate, and changes in their resonance characteristics are monitored simultaneously. Notable differences are not observed in the time dependences of the resonance characteristics, but signal-to-noise ratio obtained using the LiNbO₃ oscillator is higher than obtained by the α-quartz oscillator. From this result, it is concluded that a sensor that uses LiNbO₃ is suitable for the film-growth monitoring.