Micromechanical device and methods to fabricate same using hard mask resistant to structure release etch

A method to fabricate a device, comprising:

• providing a structure comprised of a silicon layer disposed over an insulating layer that is disposed on a silicon substrate, the silicon layer comprising at least one partially released region intended to function as a portion of an electro-mechanical device;
• forming a dielectric layer over the silicon layer;
• depositing a layer comprised of hafnium oxide over the dielectric layer;
• opening a window to expose the partially released region;
• and
• fully releasing the partially released region using a dry etching process to remove the insulating layer disposed beneath the partially released region while using the layer comprised of hafnium oxide to protect material covered by the hardmask, where
• providing the structure further comprises providing at least one transistor device formed on or in the silicon layer, and where the layer comprised of hafnium oxide covers the transistor device and metal associated with the transistor device.