Abstract: A device for measuring thickness and/or rate of thickness increase of a film comprises at least one piezoelectric element, and first and second electrodes in contact with the piezoelectric element. A method of measuring thickness and/or rate of thickness increase of a film comprises applying a voltage across a piezoelectric element from a first electrode to a second electrode, thereby causing the piezoelectric element to vibrate, and measuring the rate of vibration of the piezoelectric element. Heat may be applied to the piezoelectric element. The piezoelectric element may be formed of quartz crystal, e.g., IT-cut.