Multi-axis MEMS rate sensor device
A MEMS rate sensor device. In an embodiment, the sensor device includes a MEMS rate sensor configured overlying a CMOS substrate. The MEMS rate sensor can include a driver set, with four driver elements, and a sensor set, with six sensing elements, configured for 3-axis rotational sensing. This sensor architecture allows low damping in driving masses and high damping in sensing masses, which is ideal for a MEMS rate sensor design. Low driver damping is beneficial to MEMS rate power consumption and performance, with low driving electrical potential to achieve high oscillation amplitude.
1. A MEMS device comprising:
a layer of silicon crystal material comprising:
a first axis driver proof mass portion;
a first x-axis driver fingers portion;
a first x-axis rotational sensor physical data portion;
a second x-axis driver proof mass portion;
a second x-axis driver fingers portions;
a second x-axis rotational sensor physical data portion;
a first y-axis driver proof mass portion;
a first y-axis driver fingers portion;
a first y-axis rotational sensor physical data portion;
a second y-axis driver proof mass portion;
a second y-axis driver fingers portion;
a second y-axis rotational sensor physical data portion;
a first z-axis rotational sensor physical data portion; and
a second z-axis rotational sensor physical data portion;
wherein:
the first and second x-axis driver proof mass portions and the first and second y-axis driver proof mass portion are coupled together with flexible beams;
the first and second z-axis rotational sensor physical data portions are separated and disposed to an outside and an opposite edge of the first and second y-axis driver proof mass portions; and
the first and second z-axis rotational sensor physical data portions are separated from the flexible beams;
wherein:
the first x-axis rotational sensor physical data portion is disposed inside and being completely surrounded by the first x-axis driver proof mass portion;
the second x-axis rotational sensor physical data portion is disposed inside and being completely surrounded by the second x-axis driver proof mass portion;
the first y-axis rotational sensor physical data portion is disposed inside and being completely surrounded by the first y-axis driver proof mass portion; and
the second y-axis rotational sensor physical data portion is disposed inside and being completely surrounded by the second y-axis driver proof mass portion.
2. The device of claim 1 further comprising:
a substrate coupled to the layer of silicon crystal material comprising:
an x-axis rotation electronic feedback portion configured to convert physical data from the x-axis rotation physical data portion into x-axis rotation electrical data;
a y-axis rotation electronic feedback portion configured to convert physical data from the y-axis rotation physical data portion into y-axis rotation electrical data; and
a z-axis rotation electronic feedback portion configured to convert physical data from the z-axis rotation physical data portion to z-axis rotation electrical data.
3. The device of claim 2 wherein the x-axis rotation electrical data comprises an x-axis rotation capacitance value.
4. The device of claim 2 wherein the x-axis rotation sensor physical data portion comprises a first capacitor plate.
5. The device of claim 4
wherein the x-axis rotation electronic data portion comprises a second capacitor plate; and
wherein the physical data comprises measurement of movement of the first capacitor plate relative to the second capacitor plate.
6. The device of claim 1 wherein the x-axis driver proof mass portion comprises a first x-axis proof mass and a second x-axis proof mass;
wherein the x-axis driver fingers portion comprises a first driver fingers and a second driver fingers; and
wherein the first driver fingers drives the first driver proof mass;
wherein the second driver fingers drives the second driver proof mass; and
wherein the first driver fingers and second driver fingers have a phase relation selected from a group consisting of: in-phase, 180 degrees out-of-phase.
7. The device of claim 1 wherein the y-axis driver proof mass portion comprises a first y-axis proof mass and a second y-axis proof mass;
wherein the y-axis driver fingers portion comprises a first y-axis driver fingers and a second y-axis driver fingers; and
wherein the first driver fingers drives the first y-axis proof mass;
wherein the second driver fingers drives the second y-axis proof mass; and
wherein the first y-axis driver fingers and second-axis driver fingers have a phase relation selected from a group consisting of: in-phase, 180 degrees out-of-phase.
8. The device of claim 1 , wherein the x-axis driver proof mass portion and the y-axis driver proof mass portion are coupled to each other with flexible beams.