Disclosed are an active noise reduction acoustic unit and a sound-producing unit, the active noise reduction acoustic unit includes a casing; a baseplate which is arranged in the casing and separates the casing into a first accommodating cavity and a second accommodating cavity; the first accommodating cavity and the second accommodating cavity are in communication with each other, the second accommodating cavity being provided therein with a feedback microphone, and the feedback microphone being configured to pick up noise signals; and the first accommodating cavity is provided therein with a moving iron speaker which can vibrate and produce sound according to the noise signals.

A MEMS microphone includes a substrate, a diaphragm disposed over the substrate to cover the cavity, the diaphragm defining an air gap together with the back plate, and the diaphragm being spaced apart from the substrate, a back plate disposed over the diaphragm and in the vibration area, an upper insulation layer to cover the back plate, a plurality of chamber portions provided in the supporting area, a lower insulation layer provided under the upper insulation layer and on the substrate, and an intermediate insulation layer provided between the lower insulation layer and the upper insulation layer and disposed further from the vibration area than the chamber portions.

A MEMS microphone includes a substrate, a diaphragm disposed over the substrate to cover the cavity, the diaphragm defining an air gap together with the back plate, and the diaphragm being spaced apart from the substrate, a back plate disposed over the diaphragm and in the vibration area, an upper insulation layer to cover the back plate, a plurality of chamber portions provided in the supporting area, a lower insulation layer provided under the upper insulation layer and on the substrate, and an intermediate insulation layer provided between the lower insulation layer and the upper insulation layer and disposed further from the vibration area than the chamber portions.

In one embodiment, a method of manufacturing a semiconductor device includes oxidizing a substrate to form local oxide regions that extend above a top surface of the substrate. A membrane layer is formed over the local oxide regions and the top surface of the substrate. A portion of the substrate under the membrane layer is removed. The local oxide regions under the membrane layer are removed.

In one embodiment, a method of manufacturing a semiconductor device includes oxidizing a substrate to form local oxide regions that extend above a top surface of the substrate. A membrane layer is formed over the local oxide regions and the top surface of the substrate. A portion of the substrate under the membrane layer is removed. The local oxide regions under the membrane layer are removed.

Disclosed in embodiments of the present disclosure are a capacitive MEMS microphone, a microphone unit and an electronic device. The capacitive MEMS microphone includes: a back electrode plate; a diaphragm; and a spacer for separating the back electrode plate from the diaphragm, wherein in a state where an operating bias is applied, a ratio of a static effective displacement of the diaphragm relative to a flat position to a thickness of the diaphragm is greater than or equal to 0.5.

Disclosed in embodiments of the present disclosure are a capacitive MEMS microphone, a microphone unit and an electronic device. The capacitive MEMS microphone includes: a back electrode plate; a diaphragm; and a spacer for separating the back electrode plate from the diaphragm, wherein in a state where an operating bias is applied, a ratio of a static effective displacement of the diaphragm relative to a flat position to a thickness of the diaphragm is greater than or equal to 0.5.

A device includes a readout circuit coupled between an input node and an output node; a microelectromechanical systems (MEMS) device coupled to the input node; and a first charge controlled clamp circuit coupled between the input node and a first bias node.

A condenser microphone with at least two microphone capsules, each including a diaphragm and a backplate. The backplates of both the first capsule and second capsule having an electret bias. The first capsule having a first polar pattern, and the second capsule having a second polar pattern. The second capsule having an external voltage bias that is continuously variable over a certain voltage range. This external voltage bias can be applied to the second diaphragm or second backplate. The microphone's total polar pattern consists of a combination of the first polar pattern and the second polar pattern. Using the external voltage bias of the second capsule, the microphone's total polar pattern is continuously variable throughout a range set by the external voltage bias.

The present disclosure discloses a MEMS microphone including a printed circuit board, a shell assembled with the printed circuit board for forming a receiving space and provided with a sound hole communicating with the receiving space, a MEMS Die with a cavity accommodated in the receiving space and mounted on the shell for covering the sound hole, and an ASIC chip accommodated in the receiving space and mounted on the shell through a substrate. The cavity of the MEMS Die communicates with the sound hole. The MEMS Die electrically connects with the ASIC chip. The ASIC chip electrically connects with the substrate. The substrate electrically connects with the printed circuit board.