TY - JOUR
T1 - Development of an electret microphone in silicon
AU - Sprenkels, A.J.
AU - Groothengel, R.A.
AU - Verloop, A.J.
AU - Bergveld, P.
PY - 1989
Y1 - 1989
N2 - We describe a subminiature electret microphone, which has been realized in silicon using wafer processing techniques. The microphone consists of a rigid backplate fabricated in silicon and a 2.5 μm thick metallized Mylar foil (PETP) acting as the diaphragm. Between the diaphragm and the backplate a 20 μm thick air cavity and a 1.1 μm thick charged SiO2 layer are present. The SiO2 layer is used as the electret and generates an electric field in the air gap. The electret has been changed to 300 V using a corona-charging set-up. The time constant of the charge decay amounts to more than 100 years at ambient laboratory conditions.
The microphone cartridge, which measures 3 × 3 × 0.3 mm, shows an open-circuit sensitivity of about 2.5 mV/μbar at 1 kHz.
AB - We describe a subminiature electret microphone, which has been realized in silicon using wafer processing techniques. The microphone consists of a rigid backplate fabricated in silicon and a 2.5 μm thick metallized Mylar foil (PETP) acting as the diaphragm. Between the diaphragm and the backplate a 20 μm thick air cavity and a 1.1 μm thick charged SiO2 layer are present. The SiO2 layer is used as the electret and generates an electric field in the air gap. The electret has been changed to 300 V using a corona-charging set-up. The time constant of the charge decay amounts to more than 100 years at ambient laboratory conditions.
The microphone cartridge, which measures 3 × 3 × 0.3 mm, shows an open-circuit sensitivity of about 2.5 mV/μbar at 1 kHz.
U2 - 10.1016/0250-6874(89)80038-1
DO - 10.1016/0250-6874(89)80038-1
M3 - Article
VL - 17
SP - 509
EP - 512
JO - Sensors and actuators
JF - Sensors and actuators
SN - 0250-6874
IS - 3-4
ER -