Suspended microelectromechanical system (MEMS) devices

A microelectromechanical system (MEMS) device comprising:

• a substrate having a cavity formed therein, the cavity including a bottom surface, at least one sidewall surface extending substantially perpendicularly from the bottom surface, and an open top;
• a dielectric material covering each of the bottom surface and the at least one sidewall surface of the cavity;
• and
• a movable electromechanical device suspended in the cavity above the bottom surface through the open top, the electromechanical device including a bottom portion and side portions facing the dielectric material of the bottom surface and the dielectric material of each of the at least one sidewall surface, respectively,
• wherein the bottom surface of the cavity is substantially planar, each of the at least one sidewall surface of the cavity has a substantially linear cross-sectional profile, and the bottom surface of the cavity and the each sidewall surface of the cavity meet at a rectilinear corner, and
• wherein the bottom portion of the electromechanical device includes a plurality of projections extending toward the bottom surface of the cavity such that the bottom portion of the electromechanical device has a non-linear cross-sectional profile.

A microelectromechanical system (MEMS) device comprising:

• a substrate having a cavity formed therein, the cavity including a bottom surface, at least one sidewall surface extending substantially perpendicularly from the bottom surface, and an open top;
• a dielectric material covering each of the bottom surface and the at least one sidewall surface of the cavity;
• and
• a movable electromechanical device suspended in the cavity above the bottom surface through the open top, the electromechanical device including a bottom portion and side portions facing the dielectric material of the bottom surface and the dielectric material of each of the at least one sidewall surface, respectively,
• wherein the bottom surface of the cavity is substantially planar, each of the at least one sidewall surface of the cavity has a substantially linear cross-sectional profile, and the bottom surface of the cavity and the each sidewall surface of the cavity meet at a rectilinear corner, and
• wherein:
• the substrate includes:
• a first SOI structure having a first active layer, and
• a second SOI structure having a second active layer,
• the electromechanical device is formed using the second active layer, and
• the cavity is formed from a portion of the first active layer.

A microelectromechanical system (MEMS) device comprising:

• a substrate having a dielectric cavity formed therein, the cavity including a bottom surface, at least one sidewall surface extending substantially perpendicularly from the bottom surface, and an open top;
• and
• a movable electromechanical device suspended in the cavity above the bottom surface through the open top, the electromechanical device including a bottom portion and side portions facing the dielectric material of the bottom surface and the dielectric material of each of the at least one sidewall surface, respectively,
• wherein the bottom surface of the cavity is substantially planar, each of the at least one sidewall surface of the cavity has a substantially linear cross-sectional profile, and the bottom surface of the cavity and the each sidewall surface of the cavity meet at a rectilinear corner, and
• wherein:
• the substrate includes:
• a first SOI structure having a first active layer, and
• a second SOI structure having a second active layer,
• the electromechanical device is formed using the second active layer, and
• the cavity is formed from a portion of the first active layer.