Methods of forming MEMS diaphragms including corrugations

An acoustic transducer formed by the process of:

• providing a substrate;
• selectively etching the substrate to form at least one of an enclosed trench or an enclosed pillar on the substrate;
• depositing a first structural layer on the substrate, the first structural layer including at least one of a depression or a bump corresponding to the enclosed trench or the enclosed pillar;
• heating the first structural layer to a temperature above a glass transition temperature of the first structural layer causing the first structural layer to reflow;
• depositing a diaphragm layer on the first structural layer such that the diaphragm layer includes at least one of a downward facing corrugation corresponding to the depression or an upward facing corrugation corresponding to the bump formed in the first structural layer;
• and
• releasing the diaphragm layer, thereby forming a diaphragm suspended over the substrate.

A method, comprising:

• providing a substrate;
• depositing a first structural layer on the substrate;
• selectively etching the first structural layer to form at least one of an enclosed trench or enclosed pillar on the first structural layer;
• depositing a second structural layer on the first structural layer, the second structural layer including at least one of a depression or a bump corresponding to the at least one of the enclosed trench or the enclosed pillar formed in the first structural layer;
• heating at least the second structural layer to a temperature above a glass transition temperature of the second structural layer causing the second structural layer to reflow;
• depositing a diaphragm layer on the second structural layer such that the diaphragm layer includes at least one of a downward facing corrugation corresponding to the depression or an upward facing corrugation corresponding to the bump formed in the second structural layer;
• and
• releasing the diaphragm layer, thereby forming a diaphragm suspended over the substrate.