Patent ID: 7275436

Claim:
A device for measuring the thickness of a film made of a deposit material and/or the rate of increase of the thickness of a film made of a deposit material, comprising: at least one piezoelectric element; a first electrode, said first electrode being in contact with at least a first region of said piezoelectric element; a second electrode, said second electrode being in contact with at least a second region of said piezoelectric element, said second region being spaced from said first region; at least one source of a deposit material, said piezoelectric element being exposed to said source; and a heater which maintains said piezoelectric element at a substantially constant temperature, said heater being in direct contact with a solid body, said at least one piezoelectric element being in direct contact with said body, such that when said heater is heated, heat is transferred from said heater to said solid body by conduction, and heat is transferred from said solid body to said at least one piezoelectric element by conduction.