A Thin Film Teflon Electret Technology for Microphone Applications

Abstract

A micromachining compatible Teflon electret technology has been developed. The electret material used is thin film spin-on Teflon. A pulsed electron gun, called the Back-Lighted Thyratron (BLT), is used for charge implantation. A charge compensation method is used to measure the charge density of the electret. The electret has a saturated charge density on the order of 10 4 C/m 2 A prototype silicon micromachined electret microphone has been fabricated and tested. An open circuit sensitivity of 0.3 mV/Pa has been achieved for a hybrid microphone package.