Method for sealing and backside releasing of microelectromechanical systems

A method for encapsulating and integrating nano and/or microelectromechanical systems (MEMS) comprising:

• providing a semiconductor-on-insulator substrate comprising a handle layer, a device layer, and an insulating layer disposed between the handle and device layers;
• fabricating a transistor-based circuit in the device layer;
• covering the transistor-based circuit with a masking layer;
• fabricating a MEMS device in the handle layer;
• fabricating, in the handle layer, a sacrificial layer that immobilizes the MEMS device;
• and
• releasing the MEMS device using an etchant to remove the sacrificial layer, wherein the masking layer is resistant to the etchant and the masking layer protects the transistor-based circuit from the etchant.

A method for encapsulating and integrating nano- and/or micro-electromechanical systems (MEMS) comprising:

• providing a semiconductor-on-insulator substrate comprising a handle layer, a device layer, and an insulating layer disposed between the handle and device layers;
• fabricating a transistor-based circuit in the device layer;
• fabricating a MEMS device in the device layer;
• covering the MEMS device with an etch resistant layer;
• etching the handle layer beneath the MEMS device using the insulating layer as an etch stop;
• and
• releasing the MEMS device from the device layer through the backside of the substrate using an etchant, wherein the etch-resistant layer is resistant to the etchant and the etch-resistant layer protects the transistor-based circuit from the etchant,
• wherein the etch resistant layer extends over the MEMS device on a frontside of the substrate, wherein the etch resistant layer extends through the device layer and contacts the handle layer.