On-Chip Hotplate for Temperature Control of Cmos Saw Resonators

TL;DR

This paper introduces an integrated on-chip hotplate using polysilicon resistors to stabilize CMOS SAW resonator temperature, significantly reducing temperature coefficient of frequency for improved device stability.

Contribution

The work presents a novel on-chip hotplate design employing polysilicon resistors for temperature control of CMOS SAW resonators, validated through modeling, simulation, and experimental measurements.

Findings

Temperature coefficient of frequency reduced from -97.2 ppm/°C to -23.19 ppm/°C at 56°C

Effective temperature stabilization achieved with integrated polysilicon resistors

Validated through PDE modeling, finite element simulations, and thermal imaging

Abstract

Due to the sensitivity of the piezoelectric layer in surface acoustic wave (SAW) resonators to temperature, a method of achieving device stability as a function of temperature is required. This work presents the design, modeling and characterization of integrated dual-serpentine polysilicon resistors as a method for temperature control of CMOS SAW resonators. The design employs the oven control temperature stabilization scheme where the device's temperature is elevated to higher than Tmax to maintain constant device temperature. The efficiency of the polysilicon resistor as a heating element was verified through a 1-D partial differential equation model, 3-D CoventorWare finite element simulations and measurements using Compix thermal camera. To verify that the on-chip hotplate is effective as a temperature control method, both DC and RF measurements of the heater together with the resonator were conducted. Experimental results have indicated that the TCF of the CMOS SAW resonator of -97.2 ppm/deg C has been reduced to -23.19 ppm/deg C when heated to 56 deg C.