Various embodiments of the present disclosure are directed towards a microelectromechanical systems (MEMS) structure including an epitaxial layer overlying a MEMS substrate. The MEMS substrate comprises a moveable element arranged over a carrier substrate. The epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts overlies the epitaxial layer. A first subset of the plurality of contacts overlies the moveable element. The plurality of contacts respectively has an ohmic contact with the epitaxial layer.

A method for producing a nanocrystalline, gas-sensitive layer structure. The method for producing a nanocrystalline, gas-sensitive layer structure on a substrate comprises the steps: depositing a base layer made of a base material; depositing a doping layer made of a doping material; repeating the preceding steps; and performing a tempering step, whereby a gas-sensitive, nanocrystalline layer structure is produced.

Various embodiments of the present disclosure are directed towards a method for forming a microelectromechanical systems (MEMS) structure including an epitaxial layer overlying a MEMS substrate. The method includes bonding a MEMS substrate to a carrier substrate. The epitaxial layer is formed over the MEMS substrate, where the epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts is formed over the epitaxial layer.

A method for producing a nanocrystalline, gas-sensitive layer structure. The method for producing a nanocrystalline, gas-sensitive layer structure on a substrate comprises the steps: depositing a base layer made of a base material; depositing a doping layer made of a doping material; repeating the preceding steps; and performing a tempering step, whereby a gas-sensitive, nanocrystalline layer structure is produced.

Various embodiments of the present disclosure are directed towards a method for forming a microelectromechanical systems (MEMS) structure including an epitaxial layer overlying a MEMS substrate. The method includes bonding a MEMS substrate to a carrier substrate. The epitaxial layer is formed over the MEMS substrate, where the epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts is formed over the epitaxial layer.

Various embodiments of the present disclosure are directed towards a microelectromechanical systems (MEMS) structure including an epitaxial layer overlying a MEMS substrate. The MEMS substrate comprises a moveable element arranged over a carrier substrate. The epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts overlies the epitaxial layer. A first subset of the plurality of contacts overlies the moveable element. The plurality of contacts respectively has an ohmic contact with the epitaxial layer.

Various embodiments of the present disclosure are directed towards a method for forming an integrated chip including an epitaxial layer overlying a microelectromechanical systems (MEMS) substrate. The method includes bonding a MEMS substrate to a carrier substrate, the MEMS substrate includes monocrystalline silicon. An epitaxial layer is formed over the MEMS substrate, the epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts are formed over the epitaxial layer, the plurality of contacts respectively form ohmic contacts with the epitaxial layer.

Processes for fabricating capacitive micromachined ultrasonic transducers (CMUTs) are described, as are CMUTs of various doping configurations. An insulating layer separating conductive layers of a CMUT may be formed by forming the layer on a lightly doped epitaxial semiconductor layer. Dopants may be diffused from a semiconductor substrate into the epitaxial semiconductor layer, without diffusing into the insulating layer. CMUTs with different configurations of N-type and P-type doping are also described.

A micro-electro-mechanical device formed in a monolithic body of semiconductor material accommodating a first buried cavity; a sensitive region above the first buried cavity; and a second buried cavity extending in the sensitive region. A decoupling trench extends from a first face of the monolithic body as far as the first buried cavity and laterally surrounds the second buried cavity. The decoupling trench separates the sensitive region from a peripheral portion of the monolithic body.

Various embodiments of the present disclosure are directed towards a method for forming an integrated chip including an epitaxial layer overlying a microelectromechanical systems (MEMS) substrate. The method includes bonding a MEMS substrate to a carrier substrate, the MEMS substrate includes monocrystalline silicon. An epitaxial layer is formed over the MEMS substrate, the epitaxial layer has a higher doping concentration than the MEMS substrate. A plurality of contacts are formed over the epitaxial layer, the plurality of contacts respectively form ohmic contacts with the epitaxial layer.