US 12,391,543 B1
Resonant elements and oscillators
Renata M. Berger, Palo Alto, CA (US); Ginel C. Hill, Sunnyvale, CA (US); Paul M. Hagelin, Saratoga, CA (US); Charles I. Grosjean, Los Gatos, CA (US); Aaron Partridge, Cupertino, CA (US); Joseph C. Doll, Mountain View, CA (US); and Markus Lutz, Mountain View, CA (US)
Assigned to SiTime Corporation, Santa Clara, CA (US)
Filed by SiTime Corporation, Santa Clara, CA (US)
Filed on Jan. 2, 2024, as Appl. No. 18/402,483.
Application 17/384,535 is a division of application No. 15/627,049, filed on Jun. 19, 2017, granted, now 11,807,518, issued on Nov. 7, 2023.
Application 15/627,049 is a division of application No. 13/759,013, filed on Feb. 4, 2013, granted, now 9,695,036, issued on Jul. 4, 2017.
Application 18/402,483 is a continuation of application No. 17/384,535, filed on Jul. 23, 2021, granted, now 11,897,757.
Claims priority of provisional application 61/617,230, filed on Mar. 29, 2012.
Claims priority of provisional application 61/594,357, filed on Feb. 2, 2012.
This patent is subject to a terminal disclaimer.
Int. Cl. B81B 3/00 (2006.01); H03H 9/02 (2006.01); H03H 9/24 (2006.01)
CPC B81B 3/0024 (2013.01) [H03H 9/02448 (2013.01); H03H 9/2457 (2013.01); H03H 9/2405 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A micromachined resonator comprising:
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;
at least one connecting structure that mechanically couples together the anchored ends of the beams;
at least one electrode to sense a frequency of resonant motion of the micromachined resonator; and
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.