Annealing Effect of High Dielectric Material for Low Voltage Electrowetting on Dielectric (EWOD)

Abstract

In this paper, the high dielectric constants for Ta 2 O 5 (~18.8) and Nb 2 O 5 (~25.5) were deposited by a RF reactive magnetron sputtering and respectively annealed at 700 °C and 400 °C O 2 ambiance for 30 min in a conventional furnace. The purpose of this study is to optimize the annealing condition (various temperatures at N 2 or O 2 ambiance) of the high-dielectric-constant Ta 2 O 5 and Nb 2 O 5 films deposited by RF reactive magnetron sputtering to enhance the dielectric constant of those films to further lower the operating voltage. Based on the results, an electrowetting optical deflector (EOD) filled with the water (1% sodium dodecyl sulfate (SDS)) and dodecane was fabricated and tested, and the contact angle of the inclined liquid surface on the left and right sidewall can be varied about 70° at 9 V operating voltage. This study provides a practical way to fabricate a high dielectric constant layer for low voltage electrowetting on dielectric (EWOD) application.