| Title |
Piezoelectric Microspeakers Fabricated with High Quality AlN Thin Film |
| Authors |
이승환(Yi, Seung-Hwan) ; 정경식(Jung, Kyung-Sick) ; 김동기(Kim, Dong-Kee) ; 신광재(Shin, Gwang-Jae) |
| Keywords |
Piezoelectric Microspeaker ; AlN Film ; Sound Pressure Level ; Residual Stress |
| Abstract |
This paper reports the piezoelectric microspeakers that are audible in open air with high quality piezoelectric AlN thin film deposited onto Mo/Ti electrode. This successful achievement, compared to the previous results, is followed by manipulating two material properties: the one is to use a compressively stressed silicon nitride film as a supporting diaphragm (even tensile stressed, around +20 MPa) and the another is to use high quality AlN thin film with compressive residual stress (less than -100 MPa). With these materials, the Sound Pressure Level (SPL) of the fabricated micro speakers shows more than 60 dB from 100 Hz to 15 kHz and the highest SPL is about 100 dB at 9.3 kHz with 20 Vpeak-to-peak sinusoidal input and with 10 mm distances from the fabricated micro speakers to the reference microphone (B&K Type 2669 & 4192L). |