Thermal Effects Of Ovenized Clocks On Episeal Encapsulated Inertial Measurement Units

In this paper, we demonstrate the thermal effects of micro-ovenized clocks embedded in the device layer of a vacuum sealed MEMS inertial measurement unit. We demonstrate a novel in-plane suspension and heater that provides improved thermal isolation within a mm-scale chip, compared to in-cap heaters. We show the interaction of three resonators within a single die: an ovenized tuning fork, a resonant accelerometer, and a disk resonating gyroscope. We demonstrate that a device layer micro-oven, which operates at a tenth of the power of an encapsulation cap-layer micro-oven, has very small effects on the frequency of the other resonators in the die, thus proving good thermal isolation in our structures. We show that the in-plane heater isolation provides more than a 15X reduction of frequency deviation of adjacent sensors.