Abstract:
Microshells including a perforated pre-sealing layer and an integrated getter layer are provided. The integrated getter layer may be disposed between other layers of a perforated pre-sealing layer. The perforated pre-sealing layer may include at least one perforation, and a sealing layer may be provided on the pre-sealing layer to close the perforation.
Abstract:
A microelectromechanical systems (MEMS) device includes a tuning electrode, a drive electrode, and a resonator. The resonator is anchored to a substrate and is configured to resonate in response to a signal on the drive electrode. The MEMS device includes a tuning plate coupled to the resonator and positioned above the tuning electrode. The tuning plate is configured to adjust a resonant frequency of the resonator in response to a voltage difference between the resonator and the tuning electrode. In at least one embodiment of the MEMS device, the tuning plate and the tuning electrode are configured to adjust the resonant frequency of the resonator substantially independent of the signal on the drive electrode.
Abstract:
An apparatus and a method for compensating for a mismatch in temperature coefficients of two oscillator frequencies to match a desired frequency ratio between the two oscillator frequencies over a temperature range. In one embodiment of a temperature sensor, first and second oscillators of different temperature characteristics are coupled to a differential frequency discriminator (DFD) circuit. The DFD circuit compensates for the different characteristics in order to match a frequency difference between the first and second frequencies over a temperature range.
Abstract:
A MEMS structure having a temperature-compensated resonator member is described. The MEMS structure comprises an asymmetric stress inverter member coupled with a substrate. A resonator member is housed in the asymmetric stress inverter member and is suspended above the substrate. The asymmetric stress inverter member is used to alter the thermal coefficient of frequency of the resonator member by inducing a stress on the resonator member in response to a change in temperature.
Abstract:
MEMS resonators containing a first material and a second material to tailor the resonator's temperature coefficient of frequency (TCF). The first material has a different Young's modulus temperature coefficient than the second material. In one embodiment, the first material has a negative Young's modulus temperature coefficient and the second material has a positive Young's modulus temperature coefficient. In one such embodiment, the first material is a semiconductor and the second material is a dielectric. In a further embodiment, the quantity and location of the second material in the resonator is tailored to meet the resonator TCF specifications for a particular application. In an embodiment, the second material is isolated to a region of the resonator proximate to a point of maximum stress within the resonator. In a particular embodiment, the resonator includes a first material with a trench containing the second material.
Abstract:
A MEMS oscillator includes a resonator body and primary and secondary drive electrodes to electrostatically drive the resonator body. Primary and secondary sense electrodes sense motion of the resonator body. The primary and secondary drive and sense electrodes are configured to be used together during start-up of the MEMS oscillator. The secondary drive electrode and secondary sense electrode are disabled after start-up, while the primary drive and sense electrodes remain enabled to maintain oscillation.
Abstract:
MEMS resonators containing a first material and a second material to tailor the resonator's temperature coefficient of frequency (TCF). The first material has a different Young's modulus temperature coefficient than the second material. In one embodiment, the first material has a negative Young's modulus temperature coefficient and the second material has a positive Young's modulus temperature coefficient. In one such embodiment, the first material is a semiconductor and the second material is a dielectric. In a further embodiment, the quantity and location of the second material in the resonator is tailored to meet the resonator TCF specifications for a particular application. In an embodiment, the second material is isolated to a region of the resonator proximate to a point of maximum stress within the resonator. In a particular embodiment, the resonator includes a first material with a trench containing the second material.
Abstract:
Disclosed is an oscillator that relies on redundancy of similar resonators integrated on chip in order to fulfill the requirement of one single quartz resonator. The immediate benefit of that approach compared to quartz technology is the monolithic integration of the reference signal function, implying smaller devices as well as cost and power savings.
Abstract:
An encapsulated MEMS device and a method to form an encapsulated MEMS device are described. An apparatus includes a first substrate having a silicon-germanium seal ring disposed thereon and a second substrate having a metal seal ring disposed thereon. The metal seal ring is aligned with and bonded to the silicon-germanium seal ring to provide a sealed cavity. A MEMS device is housed in the sealed cavity. A method includes forming a silicon-germanium seal ring on a first substrate and forming a metal seal ring on a second substrate. The metal seal ring is bonded to the silicon-germanium seal ring to provide a sealed cavity that houses a MEMS device.
Abstract:
Disclosed is an oscillator that relies on redundancy of similar resonators integrated on chip in order to fulfill the requirement of one single quartz resonator. The immediate benefit of that approach compared to quartz technology is the monolithic integration of the reference signal function, implying smaller devices as well as cost and power savings.