Outgassing material coated cavity for a micro-electro mechanical system device and methods for forming the same

A micro-electro mechanical system (MEMS) device, comprising:

• a MEMS support structure bonded to a cap structure through a matrix layer;
• a first movable element located inside a first sealed chamber that is laterally bounded by the matrix layer;
• a vertically-extending trench that extends into the MEMS support structure or a portion of the cap structure that faces the matrix layer;
• and
• an outgassing-material-containing portion including a layer stack comprising an outgassing material layer and a hydrophobic coating layer, located within the vertically-extending trench, and having a surface that is physically exposed to the first sealed chamber.

A micro-electro mechanical system (MEMS) device, comprising:

• a MEMS support structure bonded to a cap structure through a matrix layer;
• a first movable element located inside a first sealed chamber that is laterally bounded by the matrix layer;
• a vertically-extending trench that extends into the MEMS support structure or into the cap structure;
• and
• a vertically-extending outgassing material portion located within the vertically-extending trench, having a surface that is physically exposed to the first sealed chamber, and having a lateral thickness that is less than one half of a width of the vertically-extending trench.