Micromechanical actuator with multiple-plane comb electrodes and methods of making

A micro-electro-mechanical comb-drive actuator (2), comprising:

• a first semiconductor layer (90) having:
• a movable element (92) supported by multiple hinges (94) to allow pivoting about an axis and having a first and a second sets of comb electrodes (93) located on opposite sides of the axis;
• and
• a stationary element (91) having a third and a fourth sets of comb electrodes (95);
• wherein the teeth of the first and the second comb electrodes (93) are interdigitated in the same plane with the teeth of the third and the fourth comb electrodes (95);
• an electrical insulation layer (100) which supports and insulates the semiconductor layers (90, 110);
• and
• a second semiconductor layer (110) having:
• a cavity (111);
• and
• a fifth and a sixth sets of stationary comb electrodes (112′, 112″) electrically isolated and located on opposite sides of the rotation axis of the movable element (92);
• wherein the teeth of the fifth and the sixth sets of comb electrodes (112′, 112″) are interdigitated vertically with the first and the second sets of comb electrodes (93) of the movable element (92);
• wherein the first and the second sets of comb electrodes (93) are coupled to a first voltage (GND), the third and the fourth sets of comb electrodes (95) are coupled to a second voltage (AC1), the fifth set of comb electrodes (112′) is coupled to a third voltage (AC2), and the sixth set of comb electrodes (112″) is coupled to a fourth voltage (AC3), and
• wherein a first oscillating voltage difference between the first and the second voltages (GND, AC1) at around twice the resonant frequency of the application, and a second oscillating voltage difference between the first and the third voltages (GND, AC2) and a third oscillating voltage difference between the first and the fourth voltages (GND, AC3) at around the resonant frequency of the application oscillate the movable element (92) about the rotation axis.