Fall 2010 IAB
September 15 to 17
Near-Zero Temperature Coefficient of Frequency for AlN Lamb Wave Resonators.
In this research, the temperature compensation of aluminum nitride (AlN) Lamb wave resonators using edge-type reflectors is experimentally demonstrated. By adding a compensating silicon dioxide (SiO2) layer with an appropriate thickness, the Lamb wave resonator can achieve a zero first-order temperature coefficient of frequency (TCF). Using a composite membrane consisting of 1 μm AlN and 0.83 μm SiO2, a Lamb wave resonator operating at 711 MHz exhibits a first-order TCF of -0.3 ppb/°C and a second-order TCF of -22.3 ppb/°C2. The temperature-dependent frequency variation is less than 250 parts per million (ppm) over a wide temperature range from -55°C to 125°C. This temperature-compensated AlN Lamb wave resonator is promising for future applications to thermally stable oscillators, filters, and sensors.