Micro-electro-mechanical system (mems) variable capacitor apparatuses and related methods

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

• a fixed capacitive electrode attached to a substrate;
• a first fixed actuation electrode and a second fixed actuation electrode attached to the substrate on opposing sides of the fixed capacitive electrode;
• a movable component comprising a first end that is fixed with respect to the substrate and a second end opposite the first end that is fixed with respect to the substrate, a center portion of the movable component being positioned above the substrate and movable with respect to the fixed capacitive electrode, the first fixed actuation electrode, and the second fixed actuation electrode, the movable component comprising:
• a first movable actuation electrode positioned above the first fixed actuation electrode;
• a second movable actuation electrode positioned above the second fixed actuation electrode;
• and
• a movable capacitive electrode positioned above the fixed capacitive electrode;
• wherein at least a portion of the movable capacitive electrode is spaced apart from the fixed capacitive electrode by a first gap;
• and
• wherein the first movable actuation electrode and the second movable actuation electrode are spaced apart from the first fixed actuation electrode and the second fixed actuation electrode, respectively, by a second gap that is larger than the first gap.

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

• a fixed actuation electrode attached to a substrate;
• a fixed capacitive electrode attached to the substrate;
• and
• a movable component positioned above the substrate and movable with respect to the fixed actuation electrode and the fixed capacitive electrode, the movable component comprising:
• a movable actuation electrode positioned above the fixed actuation electrode;
• a movable capacitive electrode positioned above the fixed capacitive electrode;
• and
• at least one standoff bump attached to the movable component at or near the movable actuation electrode;
• wherein at least a portion of the movable capacitive electrode is spaced apart from the fixed capacitive electrode by a first gap;
• wherein the movable actuation electrode is spaced apart from the fixed actuation electrode by a second gap that is larger than the first gap;
• and
• wherein the at least one standoff bump protrudes from the movable actuation electrode a distance that is substantially equal to the difference between the dimensions of the first gap and the second gap.

A method for manufacturing a micro-electro-mechanical system (MEMS) variable capacitor, the method comprising:

• depositing a fixed actuation electrode on a substrate;
• depositing a fixed capacitive electrode on the substrate;
• depositing a sacrificial layer over the fixed actuation electrode and the fixed capacitive electrode;
• etching the sacrificial layer to form a recess in a region of the sacrificial layer above the fixed capacitive electrode;
• depositing a movable actuation electrode on the sacrificial layer above the fixed actuation electrode;
• depositing a movable capacitive electrode in the recess of the sacrificial layer above the fixed capacitive electrode;
• depositing a structural material layer on the movable actuation electrode and the movable capacitive electrode;
• and
• removing the sacrificial layer such that the movable actuation electrode, the movable capacitive electrode, and the structural material layer define a movable component suspended above the substrate and movable with respect to the fixed actuation electrode and the fixed capacitive electrode;
• wherein at least a portion of the movable capacitive electrode is spaced apart from the fixed capacitive electrode by a first gap;
• and
• wherein the movable actuation electrode is spaced apart from the fixed actuation electrode by a second gap that is larger than the first gap.