1. MICROMACHINED PIEZOELECTRIC MICROSPEAKERS FABRICATED WITH HIGH QUALITY ALN THIN FILM
- Author
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Seunghwan Yi, Dongki Kim, Kyongwon Seo, Soonchul Ur, JongSeon Park, and Hyongjung Kim
- Subjects
Materials science ,business.industry ,Diaphragm (acoustics) ,Condensed Matter Physics ,Floating electrode ,Signal ,Piezoelectricity ,Electronic, Optical and Magnetic Materials ,Quality (physics) ,Control and Systems Engineering ,Materials Chemistry ,Ceramics and Composites ,Optoelectronics ,Electrical and Electronic Engineering ,Thin film ,business ,Sound pressure ,Voltage - Abstract
This paper describes the micromachined piezoelectric microspeakers that can produce the audible signal with 20 V peak-to-peak input voltages. The diaphragm size is 4 × 4 mm2 and the thickness of diaphragm is around 1 micron meter except partially etched piezoelectric area. The maximum sound output pressure of the microspeaker is even higher than ever before with a small diaphragm in high frequency range around 10 kHz. This successful result bases upon using high quality AlN thin film. The deposited AlN thin film shows c-axis oriented columnar structure and very fine grains. The highest SPL (Sound Pressure Level) measured from 300 Hz to 12 kHz shows about 100 dB around 10 kHz in case of circular type microspeaker and about 76 dB in case of cross type, respectively.
- Published
- 2007
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