PECVD SILICON-NITRIDE DIAPHRAGMS FOR CONDENSER MICROPHONES

[摘要] The application of plasma-enhanced chemical vapour deposited (PECVD) silicon nitride as a diaphragm material for condenser microphones has been investigated. By means of adjusting the SiH4/NH3 gas-flow composition, silicon-rich silicon nitride films have been obtained with a relatively low tensile stress. Aluminum can be etched selectively with respect to the silicon nitride films. Using aluminum as a sacrificial layer, 300 x 300-mu-m silicon nitride diaphragms have been made. Admittance measurements on silicon nitride capacitances have shown that the insulating properties are sufficiently good for application as a microphone diaphragm.

[发布日期] 1991-05-01