To implement a single-chip ultrasonic imaging solution, on-chip signal processing may be employed in the receive signal path to reduce data bandwidth and a high-speed serial data module may be used to move data for all received channels off-chip as digital data stream. The digitization of received signals on-chip allows advanced digital signal processing to be performed on-chip, and thus permits the full integration of an entire ultrasonic imaging system on a single semiconductor substrate. Various novel waveform generation techniques, transducer configuration and biasing methodologies, etc., are likewise disclosed. HIFU methods may additionally or alternatively be employed as a component of the “ultrasound-on-a-chip” solution disclosed herein.

A method includes forming a front-end-of-the-line (FEOL) element over a substrate; forming a back-end-of-the-line (BEOL) element over the FEOL element; forming an interconnection structure over the substrate; forming a conductive shielding layer electrically connected to the interconnection structure and vertically overlapping the FEOL element and the BEOL element, wherein the conductive shielding layer is grounded to the substrate through the interconnection structure; and forming a dielectric layer covering the conductive shielding layer.

Various embodiments of the present disclosure are directed towards an electronic device that comprises a semiconductor substrate having a first surface opposite a second surface. The semiconductor substrate at least partially defines a cavity. A first microelectromechanical systems (MEMS) device is disposed along the first surface of the semiconductor substrate. The first MEMS device comprises a first backplate and a diaphragm vertically separated from the first backplate. A second MEMS device is disposed along the first surface of the semiconductor substrate. The second MEMS device comprises spring structures and a moveable element. The spring structures are configured to suspend the moveable element in the cavity. A segment of the semiconductor substrate continuously laterally extends from under a sidewall of the first MEMS device to under a sidewall of the second MEMS device.

A method includes bonding a supporting substrate to a semiconductor substrate of a wafer. A bonding layer is between, and is bonded to both of, the supporting substrate and the semiconductor substrate. A first etching process is performed to etch the supporting substrate and to form an opening, which penetrates through the supporting substrate and stops on the bonding layer. The opening has substantially straight edges. The bonding layer is then etched. A second etching process is performed to extend the opening down into the semiconductor substrate. A bottom portion of the opening is curved.

A CMOS-MEMS humidity sensor, comprising: a complementary metal oxide semiconductor (CMOS) ASIC readout circuit and a microelectromechanical system (MEMS) humidity sensor. The MEMS humidity sensor is provided on the ASIC readout circuit. The ASIC readout circuit comprises: a substrate, a heating resistor layer, a metal layer, and dielectric layers, the heating resistor layer being located above the substrate, the metal layer being located above the heating resistor layer, and the substrate, the heating resistor layer, and the metal layer being partitioned by dielectric layers. The MEMS humidity sensor comprises: an aluminum electrode layer, a passivation layer, and a humidity sensitive layer, the passivation layer being located above the aluminum electrode layer, and the humidity sensitive layer being located above the passivation layer. The provision of heating resistors in the ASIC circuit realizes the heating function and satisfies the requirements of the standard CMOS process, so that the CMOS-MEMS integrated humidity sensor can be used stably under low temperature and high humidity conditions.

A nanosheet MEMS sensor device and method are described for integrating the fabrication of nanosheet transistors (61) and MEMS sensors (62) in a single nanosheet process flow by forming separate nanosheet transistor and MEMS sensor stacks (12A-16A, 12B-16B) of alternating Si and SiGe layers which are selectively processed to form gate electrodes (49A-C) which replace the silicon germanium layers in the nanosheet transistor stack, to form silicon fixed electrodes using silicon layers (13B-2, 15B-2) on a first side of the MEMS sensor stack, and to form silicon cantilever electrodes using silicon layers (13B-1, 15B-1) on a second side of the MEMS sensor stack by forming a narrow trench opening (54) in the MEMS sensor stack to expose and remove remnant silicon germanium layers on the second side in the MEMS sensor stack.

The present invention discloses a micro-electro-mechanical system silicon on insulator (MEMS SOI) pressure sensor and a method for preparing the same. The pressure sensor includes a bulk silicon layer, a buried oxide layer, a substrate, a varistor, a passivation layer, and an electrode layer. The varistor is obtained by means of photolithography and ion implantation on a device layer of an SOI wafer. The passivation layer is SiO.sub.2 formed by means of annealing treatment on the SOI wafer. An annealing atmosphere is one of pure O.sub.2, a gas mixture of O.sub.2/H.sub.2O, a gas mixture of O.sub.2/NO, a gas mixture of O.sub.2/HCl, and a gas mixture of O.sub.2/CHF.sub.3. By means of the annealing treatment, the damage to a surface of the buried oxide layer as a result of over-etching during formation of the varistor by means of photolithography is eliminated and the unstability of the sensor caused by body and interface defects of the passivation layer and trapped charges thereof is resolved. A trench is formed at the buried oxide layer and the bulk silicon layer directly below the varistor, which helps overcome defects as a result of doped impurities entering the buried oxide layer below the varistor, and helps improve the sensitivity of the sensor.

A MEMS device and a manufacturing method thereof. The manufacturing method comprises: forming a CMOS circuit; and forming a MEMS module on the CMOS circuit which is coupling to the MEMS module and configured to drive the MEMS module. Forming the MEMS module comprises: forming a protective layer; forming a sacrificial layer in the protective layer; forming a first electrode on the protective layer and on the sacrificial layer so that the first electrode covers the sacrificial layer, and electrically coupling the first electrode to the CMOS circuit; forming a piezoelectric layer on the first electrode and above the sacrificial layer; forming a second electrode on the piezoelectric layer and electrically coupling the second electrode to the CMOS circuit; forming a through hole to reach the sacrificial layer; and forming a cavity by removing the sacrificial layer through the through hole.

A radio frequency (RF) front-end (RFFE) device includes a die having a front-side dielectric layer on an active device. The active device is on a first substrate. The RFFE device also includes a microelectromechanical system (MEMS) device. The MEMS device is integrated on the die at a different layer than the active device. The MEMS device includes a cap layer composed of a cavity in the front-side dielectric layer of the die. The cavity in the front-side dielectric layer is between the first substrate and a second substrate. The cap is coupled to the front-side dielectric layer.

Ultrasonic sensing approaches are described with integrated MEMS-CMOS implementations. Embodiments include ultrasonic sensor arrays for which PMUT structures of individual detector elements are at least partially integrated into the CMOS ASIC wafer. MEMS heating elements are integrated with the PMUT structures by integrating under the PMUT structures in the CMOS wafer and/or over the PMUT structures (e.g., in the protective layer). For example, embodiments can avoid wafer bonding and can reduce other post processing involved with conventional manufacturing of PMUT ultrasonic sensors, while also improving thermal response.