Long-term stability of a hermetically packaged MEMS disk oscillator

A low phase noise oscillator referenced to a wineglass disk MEMS resonator, hermetically vacuum packaged in a purpose-built packaging system, and measured in a double-oven, has provided a first long-term measurement of a MEMS disk oscillator over 10 months. After an initial burn-in period, the frequency can be seen to stabilize to within the short-term measurement variation of 300 ppb over a period of months, a significant improvement from previous studies on other MEMS resonator types, where frequency fluctuations were between 3.1 ppm and 1.2 ppm over similar time scales. Including burn-in, the total observed aging of 10 ppm is now on par with many consumer-grade quartz oscillators designed for timing applications and sufficient for target wireless sensor network applications.