Self-aligned dielectric liner structure for protection in MEMS comb actuator

A microelectromechanical system (MEMS) comb actuator comprising:

• a comb structure comprising:
• a support layer comprising a semiconductor material, and
• a first protrusion and a second protrusion comprising the semiconductor material, extending away from the support layer in a first direction, and separated from one another in a second direction normal to the first direction;
• a third protrusion comprising the semiconductor material and extending away from the support layer in the first direction, wherein the second protrusion is arranged between the first and third protrusions;
• and
• a dielectric liner structure arranged over the comb structure and comprising:
• a first sidewall portion completely covering a first sidewall of the first protrusion, and
• a second sidewall portion completely covering a second sidewall of the first protrusion, and
• a connective portion directly connecting a topmost surface of the second protrusion to a topmost surface of the third protrusion, wherein a third direction is normal to the topmost surfaces of the second and third protrusions, wherein the third direction is perpendicular to the first and second directions,
• wherein the first and second sidewall portions have respective uniform thicknesses measured in the second direction,
• wherein a maximum distance of the dielectric liner structure that surrounds the first protrusion and that is measured in the second direction is between an outermost sidewall of the first sidewall portion and an outermost sidewall of the second sidewall portion, wherein the outermost sidewall of the first sidewall portion faces away from the first protrusion, and wherein the outermost sidewall of the second sidewall portion faces away from the first protrusion.

A microelectromechanical system (MEMS) comb actuator comprising:

• a comb structure comprising:
• a support layer comprising a semiconductor material, and
• a first protrusion and a second protrusion comprising the semiconductor material, extending away from the support layer in a first direction, and separated from one another in a second direction normal to the first direction;
• and
• a dielectric liner structure arranged over the comb structure and comprising:
• a first sidewall portion completely covering a first sidewall of the first protrusion,
• a second sidewall portion completely covering a second sidewall of the first protrusion, and
• a top portion arranged on a topmost surface of the first protrusion, wherein the top portion couples the first sidewall portion to the second sidewall portion of the dielectric liner structure, wherein a third direction is normal to the topmost surface of the first protrusion, wherein the third direction is perpendicular to the first and second directions,
• wherein the first and second sidewall portions have respective uniform thicknesses measured in the second direction,
• wherein a maximum distance of the dielectric liner structure that surrounds the first protrusion and that is measured in the second direction is between an outermost sidewall of the first sidewall portion and an outermost sidewall of the second sidewall portion, wherein the outermost sidewall of the first sidewall portion faces away from the first protrusion, wherein the outermost sidewall of the second sidewall portion faces away from the first protrusion, and
• wherein the top portion of the dielectric liner structure comprises a first rounded surface that couples a topmost surface of the top portion to the outer sidewall of the first sidewall portion, and wherein the top portion of the dielectric liner structure further comprises a second rounded surface that couples the topmost surface of the top portion to the outer sidewall of the second sidewall portion.