Microelectromechanical device having a stiffened support beam, and methods of forming stiffened support beams in MEMS

A method of forming a microelectromechanical device comprising a mass element, the method comprising:

• depositing a substrate layer;
• forming the mass element by removing at least a portion of the substrate layer, the resulting mass element defining an area of interest free of contact with the substrate;
• forming a first beam member by removing at least a portion of the substrate, the resulting first beam member defined by a first fixed end connected to the substrate, and a first free end connected to the mass element;
• forming a second beam member by removing at least a portion of the substrate, the resulting second beam member defined by a second fixed end connected to the substrate, and a second free end connected to the mass element, the second beam member being spaced apart from the first beam member;
• forming a cross member by removing at least a portion of the substrate, the first cross member connecting the first beam member and the second beam member;
• and
• wherein the substrate is deposited as a plurality of layers, and wherein the first cross member comprises a boron diffusion in the substrate.

A microelectromechanical device defined within a substrate of a MEMS, comprising:

• a mass element defining an area of interest;
• a support beam supporting the mass element in spaced-apart relationship from the substrate, the support beam comprising:
• a first beam member defined by a first fixed end connected to the substrate, and a first free end connected to the mass element;
• a second beam member defined by a second fixed end connected to the substrate, and a second free end connected to the mass element, the second beam member being spaced apart from the first beam member;
• wherein each of the beam members is defined by an upper edge and a lower edge;
• a first cross member connecting the first beam member and the second beam member at the upper edge of the beam members, but not at the lower edge of the beam members;
• and
• a second cross member connecting the first beam member and the second beam member at the lower edge of the beam members, but not at the upper edge of the beam members.

A microelectromechanical device defined within a substrate of a MEMS, comprising:

• a mass element defining an area of interest;
• a support beam supporting the mass element in spaced-apart relationship from the substrate, the support beam comprising:
• a first beam member defined by a first fixed end connected to the substrate, and a first free end connected to the mass element;
• a second beam member defined by a second fixed end connected to the substrate, and a second free end connected to the mass element, the second beam member being spaced apart from the first beam member;
• wherein each of the beam members is defined by an upper edge and a lower edge;
• and
• a first cross member oriented proximate to only one of the upper edges or the lower edges of, and connecting, the first beam member and the second beam member.