Patent ID: 9263192
Filing Date: 2016-02-16
CPC Classification: H01G,H02N

Claim Text:
1. A method for forming an electret containing positive ions, comprising: a first step of containing water vapor including ions having positive electric charge to a silicon substrate to which heat is being applied, and forming an oxide layer including those ions upon the silicon substrate; a second step of, along with applying an electric field that makes the side of the oxide layer that does not contact the silicon substrate be a negative side, and that makes the side of the silicon substrate that does not contact the oxide layer be a positive side, also applying heat to the substrate upon that the oxide layer has been formed in a hydrogen atmosphere, and causing the ions included in the oxide layer to shift in the oxide layer to its side that does not contact the silicon substrate; and a third step, performed after the second step, of contacting water vapor including a chemical substance, in an atmosphere of an inactive gas, for forming a hydrophobic chemically absorbed monomolecular layer against the silicon substrate upon which the oxide layer has been formed, and thus forming a hydrophobic membrane upon surface of the oxide layer; wherein the second step and the third step are performed continuously within one common vessel.