Abstract: An ultrasound device is described. The ultrasound device may include a cavity, a membrane, and a sensing electrode. When an electrical signal is applied to the sensing electrode and a static bias is applied to the membrane, the membrane vibrates within the cavity and produces ultrasonic signals. The cavity, the membrane, and the sensing electrode may be considered a capacitive micromachined ultrasonic transducer (CMUT). The sensing electrode may be shaped as a ring, whereby the central portion of the sensing electrode is removed. Removal of the central portion of the sensing electrode may reduce the parasitic capacitance without substantially affecting the production of ultrasonic signals by the CMUT. This, in turn, can result in an increase in the signal-to-noise ratio (SNR) of the ultrasonic signals. The ultrasound device may further include a bond pad configured for wire bonding, and a trench electrically isolating the bond pad from the membrane.

Abstract: Aspects of the technology described herein relate to built-in self-testing (BIST) of circuitry (e.g., a pulser or receive circuitry) and/or transducers in an ultrasound device. A BIST circuit may include a transconductance amplifier coupled between a pulser and receive circuitry, a capacitor network coupled between a pulser and receive circuitry, and/or a current source couplable to the input terminal of receive circuitry to which a transducer is also couplable. The collapse voltages of transducers may be characterized using BIST circuitry, and a bias voltage may be applied to the membranes of the transducers based at least in part on their collapse voltages. The capacitances of transducers may also be measured using BIST circuitry and a notification may be generated based on the sets of measurements.

Abstract: Circuitry for an ultrasound device is described. The ultrasound device may include a symmetric switch positioned between a pulser and an ultrasound transducer. The pulser may produce bipolar pulses. The symmetric switch may selectively isolate a receiver from the pulser and the ultrasound transducer during a transmit mode of the device, when the bipolar pulses are provided by the pulser to the ultrasound transducer for transmission, and may selectively permit the receiver to receive signals from the ultrasound transducer during a receive mode. The symmetric switch may be provided with a well switch to remove well capacitances in a signal path of the device.

Abstract: Aspects of the technology described herein relate to built-in self-testing (BIST) of circuitry (e.g., a pulser or receive circuitry) and/or transducers in an ultrasound device. A BIST circuit may include a transconductance amplifier coupled between a pulser and receive circuitry, a capacitor network coupled between a pulser and receive circuitry, and/or a current source couplable to the input terminal of receive circuitry to which a transducer is also couplable. The collapse voltages of transducers may be characterized using BIST circuitry, and a bias voltage may be applied to the membranes of the transducers based at least in part on their collapse voltages. The capacitances of transducers may also be measured using BIST circuitry and a notification may be generated based on the sets of measurements.

Abstract: A method of forming an ultrasound transducer device includes bonding a membrane to a substrate so as to form a sealed cavity between the membrane and the substrate. An exposed surface located within the sealed cavity includes a getter material that is electrically isolated from a bottom electrode of the cavity.

Abstract: An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.

Abstract: Aspects of the technology described herein relate to an ultrasound device including a first die that includes an ultrasonic transducer, a first application-specific integrated circuit (ASIC) that is bonded to the first die and includes a pulser, and a second ASIC in communication with the second ASIC that includes integrated digital receive circuitry. In some embodiments, the first ASIC may be bonded to the second ASIC and the second ASIC may include analog processing circuitry and an analog-to-digital converter. In such embodiments, the second ASIC may include a through-silicon via (TSV) facilitating communication between the first ASIC and the second ASIC. In some embodiments, SERDES circuitry facilitates communication between the first ASIC and the second ASIC and the first ASIC includes analog processing circuitry and an analog-to-digital converter. In some embodiments, the technology node of the first ASIC is different from the technology node of the second ASIC.

Abstract: Aspects of the technology described herein relate to ultrasound circuits that employ a differential ultrasonic transducer element, such as a differential micromachined ultrasonic transducer (MUT) element. The differential ultrasonic transducer element may be coupled to an integrated circuit that is configured to operate the differential ultrasonic transducer element in one or more modes of operation, such as a differential receive mode, a differential transmit mode, a single-ended receive mode, and a single-ended transmit mode.

Abstract: Aspects of the technology described herein relate to an ultrasound device including a first die that includes an ultrasonic transducer, a first application-specific integrated circuit (ASIC) that is bonded to the first die and includes a pulser, and a second ASIC in communication with the second ASIC that includes integrated digital receive circuitry. In some embodiments, the first ASIC may be bonded to the second ASIC and the second ASIC may include analog processing circuitry and an analog-to-digital converter. In such embodiments, the second ASIC may include a through-silicon via (TSV) facilitating communication between the first ASIC and the second ASIC. In some embodiments, SERDES circuitry facilitates communication between the first ASIC and the second ASIC and the first ASIC includes analog processing circuitry and an analog-to-digital converter. In some embodiments, the technology node of the first ASIC is different from the technology node of the second ASIC.

Abstract: Aspects of the technology described herein relate to built-in self-testing (BIST) of circuitry (e.g., a pulser or receive circuitry) and/or transducers in an ultrasound device. A BIST circuit may include a transconductance amplifier coupled between a pulser and receive circuitry, a capacitor network coupled between a pulser and receive circuitry, and/or a current source couplable to the input terminal of receive circuitry to which a transducer is also couplable. The collapse voltages of transducers may be characterized using BIST circuitry, and a bias voltage may be applied to the membranes of the transducers based at least in part on their collapse voltages. The capacitances of transducers may also be measured using BIST circuitry and a notification may be generated based on the sets of measurements.

Abstract: Aspects of the technology described herein relate to built-in self-testing (BIST) of circuitry (e.g., a pulser or receive circuitry) and/or transducers in an ultrasound device. A BIST circuit may include a transconductance amplifier coupled between a pulser and receive circuitry, a capacitor network coupled between a pulser and receive circuitry, and/or a current source couplable to the input terminal of receive circuitry to which a transducer is also couplable. The collapse voltages of transducers may be characterized using BIST circuitry, and a bias voltage may be applied to the membranes of the transducers based at least in part on their collapse voltages. The capacitances of transducers may also be measured using BIST circuitry and a notification may be generated based on the sets of measurements.

Abstract: An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.

Abstract: Aspects of the technology described herein relate to ultrasound circuits that employ a differential ultrasonic transducer element, such as a differential micromachined ultrasonic transducer (MUT) element. The differential ultrasonic transducer element may be coupled to an integrated circuit that is configured to operate the differential ultrasonic transducer element in one or more modes of operation, such as a differential receive mode, a differential transmit mode, a single-ended receive mode, and a single-ended transmit mode.

Abstract: Aspects of the technology described herein relate to ultrasound circuits that employ a differential ultrasonic transducer element, such as a differential micromachined ultrasonic transducer (MUT) element. The differential ultrasonic transducer element may be coupled to an integrated circuit that is configured to operate the differential ultrasonic transducer element in one or more modes of operation, such as a differential receive mode, a differential transmit mode, a single-ended receive mode, and a single-ended transmit mode.

Abstract: An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.

Abstract: Circuitry for an ultrasound device is described. The ultrasound device may include a symmetric switch positioned between a pulser and an ultrasound transducer. The pulser may produce bipolar pulses. The symmetric switch may selectively isolate a receiver from the pulser and the ultrasound transducer during a transmit mode of the device, when the bipolar pulses are provided by the pulser to the ultrasound transducer for transmission, and may selectively permit the receiver to receive signals from the ultrasound transducer during a receive mode. The symmetric switch may be provided with a well switch to remove well capacitances in a signal path of the device.

Abstract: 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.

Abstract: A method of forming an ultrasound transducer device includes bonding a membrane to a substrate so as to form a sealed cavity between the membrane and the substrate. An exposed surface located within the sealed cavity includes a getter material that is electrically isolated from a bottom electrode of the cavity.

Abstract: An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.

Abstract: An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.