SILICON MICROFABRICATED HORNS FOR POWER ULTRASONICS

As part of a study of silicon surgical tools, silicon ultrasonic hems for impedance transformation have been made using bulk micromachining. The ultrasonic amplification of silicon stepped, linear, exponential, and catenoidal half-wavelength horns actuated by piezoelectric lead-z irconate-titanate (PZT) plates is measured and found to agree well wit h predictions from a numerical model. With the catenoidal horn, a maxi mum ultrasonic velocity of 14.2 m s(-1) is obtained with a displacemen t of 35 mu m measured at 64.5 kHz at 150 V-pp drive. By way of compari son, in cataract surgery a particle velocity of only 11.9 m s(-1) is u sed.