Micro-mechanical system employing electrostatic actuator and fabrication methods of same

A micro-mechanical system, comprising:

• a base;
• a rotatable element;
• a flexure, connected to the rotatable element and the base;
• extending along a rotational axis of the rotatable element;
• a vertical electrostatic actuator comprising a mobile electrode integrated as part of the flexure and at least one stationary electrode located on the base;
• and
• a comb-drive actuator formed on the rotatable element and the base.

A method of fabricating an electrostatic actuator, comprising:

• providing a substrate;
• forming a first insulating layer over the substrate;
• forming a first conductive layer over the first insulating layer;
• forming a second insulating layer over the first conductive layer;
• forming a second conductive layer over the second insulating layer;
• depositing a mask on the second conductive layer that defines mobile and stationary electrodes of the electrostatic actuator;
• removing the unmasked portions of first and second conductive layers and the second insulating layer;
• and
• removing portions of the first insulating layer to release the mobile electrode from the substrate.

A method of fabricating an electrostatic actuator, comprising:

• providing a substrate;
• forming an insulating layer over the substrate;
• forming a first semiconductor layer over the insulating layer;
• forming a second semiconductor layer over the first semiconductor layer, the second semiconductor layer being a type different from the first semiconductor layer so as to form a pn-structure;
• depositing a first mask on the second semiconductor layer that defines mobile and stationary electrodes of the electrostatic actuator;
• depositing a second mask over the first mask;
• removing portions of the first mask not covered by the second mask;
• removing the unmasked portions of first and second semiconductor layers to form the mobile and stationary electrodes;
• and
• removing portions of the first insulating layer to release the mobile electrode from the substrate.