Method of providing a hydrophobic layer and condenser microphone having such a layer

A condenser microphone comprising:

• a diaphragm;
• a back-plate, wherein an inner surface of said diaphragm forms a capacitor in combination with an inner surface of said back-plate, said back-plate and/or said diaphragm being provided with a number of openings, wherein the static distance between said diaphragm and said back-plate is smaller than 10 μm;
• and
• a hydrophobic layer, provided on said inner surface of the back-plate and/or on said inner surface of the diaphragm.

A microelectromechanical microphone, comprising:

• a diaphragm and a back-plate with an air gap therebetween, the diaphragm and a back-plate including respective inner surfaces forming a capacitor, the respective inner surfaces being made of a hydrophobic or hydrophilic materials;
• a number of openings leading to the air gap;
• and
• a hydrophobic molecular monolayer coating on the inner surface of the diaphragm or the back-plate, wherein molecules of the molecular monolayer are cross-linked and multi-bounded to the inner surface of the diaphragm or the back-plate.

A microelectromechanical microphone, comprising:

• a diaphragm having an inner surface;
• a back-plate having an inner surface that, together with the inner surface of the diaphragm, forms a capacitor, wherein the static distance between the back-plate and the diaphragm does not exceed 10 μm;
• and
• a hydrophobic layer on the inner surface of the diaphragm and the inner surface of the back-plate, the hydrophobic layer being deposited through a number of openings provided in at least one of (i) the back-plate, (ii) the diaphragm, or (ii) gaps at a periphery of the back-plate and the diaphragm.

A microelectromechanical microphone, comprising:

• a diaphragm and a back-plate defining an air gap between respective inner surfaces thereof, the respective inner surfaces forming a capacitor, the static distance between the diaphragm and the back-plate not exceeding 10 μm;
• a number of openings leading to the air gap;
• and
• a hydrophobic layer deposited through the number of openings into the air gap to form a structured monolayer on at least one of the inner surface of the diaphragm or the inner surface of the back-plate.