Resonant elements and oscillators

A device comprising:

• a first die, having a micromachined resonator and at least one electrode to sense a frequency of resonant motion of the micromachined resonator, wherein the micromachined resonator comprises first, second, third and fourth beams, each of the beams comprising at least one layer of crystal silicon having an impurity dopant having concentration which is greater than or equal to 1019 cm−3, each of the beams an anchored end and a swinging end, and at least one connecting structure that mechanically couples together the anchored ends of the beams;
• and
• a second die having electronic circuitry that is structured so as to, during operation of the integrated circuit package, excite the micromachined resonator to vibrating motion and to generate, from a signal provided by the at least one electrode, a timing signal;
• wherein
• the micromachined resonator has a first axis,
• the swinging end of the first beam and the swinging end of the second beam are arranged symmetrically about the first axis, and are configured to simultaneously deflect under the application of electrical stimuli, in a common direction along a second axis perpendicular to the first axis,
• the swinging end of the third beam and the swinging end of the fourth beam are also arranged symmetrically about the first axis, and are also configured to simultaneously deflect under the application of the electrical stimuli, in a common direction along the second axis,
• the swinging end of the first beam and the swinging end of the third beam are configured to simultaneously deflect under the application of the electrical stimuli in opposite directions along the second axis,
• the swinging end of the second beam and the swinging end of the fourth beam are configured to simultaneously deflect under the application of the electrical stimuli in opposite directions along the second axis,
• the at least one layer of crystal silicon has a silicon crystal axis,
• the micromachined resonator is oriented, relative to the silicon crystal axis, such that a first two of the first beam, the second beam, the third beam and the fourth beam are oriented at respective, reciprocal angles about the silicon crystal axis and such that a second two of the first beam, the second beam, the third beam and the fourth beam are oriented at respective, reciprocal angles about the silicon crystal axis,
• the first two and the second two are oriented at one or more angles relative to each other, such that a contribution of a temperature coefficient of frequency (TCF) of the micromachined resonator from the first two is substantially negated by a contribution to the TCF from the second two, and
• the sensed frequency of resonant motion is dependent on motion of the four beams.

An oscillator integrated circuit device comprising:

• a first die, having a micromachined resonator and at least one electrode to sense a frequency of resonant motion of the micromachined resonator, wherein the micromachined resonator comprises first, second, third and fourth beams, each of the beams comprising at least one layer of crystal silicon having an impurity dopant having concentration which is greater than or equal to 1019 cm−3, each of the beams an anchored end and a swinging end, and at least one connecting structure that mechanically couples together the anchored ends of the beams;
• a second die having electronic circuitry that is structured so as to, during operation of the integrated circuit package, excite the micromachined resonator to vibrating motion and to generate, from a signal provided by the at least one electrode, a timing signal;
• an encapsulant that in combination with one or more structures, insulates the first die from an ambient environment external to the oscillator integrated circuit device;
• and
• one or more electrical contacts on an exterior surface of the oscillator integrated circuit device, the one or more electrical contacts to provide the timing signal as an output of the oscillator integrated circuit device;
• wherein
• the micromachined resonator has a first axis,
• the swinging end of the first beam and the swinging end of the second beam are arranged symmetrically about the first axis, and are configured to simultaneously deflect under the application of electrical stimuli, in a common direction along a second axis perpendicular to the first axis,
• the swinging end of the third beam and the swinging end of the fourth beam are also arranged symmetrically about the first axis, and are also configured to simultaneously deflect under the application of the electrical stimuli, in a common direction along the second axis,
• the swinging end of the first beam and the swinging end of the third beam are configured to simultaneously deflect under the application of the electrical stimuli in opposite directions along the second axis,
• the swinging end of the second beam and the swinging end of the fourth beam are configured to simultaneously deflect under the application of the electrical stimuli in opposite directions along the second axis,
• the at least one laver of crystal silicon has a silicon crystal axis,
• the micromachined resonator is oriented, relative to the silicon crystal axis, such that a first two of the first beam, the second beam, the third beam and the fourth beam are oriented at respective, reciprocal angles about the silicon crystal axis and such that a second two of the first beam, the second beam, the third beam and the fourth beam are oriented at respective, reciprocal angles about the silicon crystal axis,
• the first two and the second two are oriented at one or more angles relative to each other, such that a contribution of a temperature coefficient of frequency (TCF) of the micromachined resonator from the first two is substantially negated by a contribution to the TCF from the second two, and
• the sensed frequency of resonant motion is dependent on motion of the four beams.