TY - JOUR
T1 - Capacitive microphone with low-stress polysilicon membrane and high-stress polysilicon backplate
AU - Torkkeli, Altti
AU - Rusanen, Outi
AU - Saarilahti, Jaakko
AU - Seppä, Heikki
AU - Sipola, Hannu
AU - Hietanen, Jarmo
PY - 2000/8/25
Y1 - 2000/8/25
N2 - A capacitive single-chip silicon microphone with very low-stress polysilicon membrane was fabricated. A mechanism for stress-releasing due to the high stress of the perforated membrane was introduced. With the achieved stress level of 2 MPa, a microphone with the membrane area of 1 mm2 can be optimally designed, although the measured components did not show the optimal resolution due to excessive acoustic resistance. With a membrane area of 1 mm2, the acoustical sensitivity was 4 mV/Pa (at 1 kHz) and the noise equivalent sound level was 33.5 dB (A), which are adequate values for many applications. The packaged components were tested with a thermal cycle between -40 °C and +60 °C, and due to low packaging-related stresses, no buckling of the membranes was observed.
AB - A capacitive single-chip silicon microphone with very low-stress polysilicon membrane was fabricated. A mechanism for stress-releasing due to the high stress of the perforated membrane was introduced. With the achieved stress level of 2 MPa, a microphone with the membrane area of 1 mm2 can be optimally designed, although the measured components did not show the optimal resolution due to excessive acoustic resistance. With a membrane area of 1 mm2, the acoustical sensitivity was 4 mV/Pa (at 1 kHz) and the noise equivalent sound level was 33.5 dB (A), which are adequate values for many applications. The packaged components were tested with a thermal cycle between -40 °C and +60 °C, and due to low packaging-related stresses, no buckling of the membranes was observed.
KW - capacitive
KW - microphone
KW - polysilicon
KW - stress
UR - http://www.scopus.com/inward/record.url?scp=0034245591&partnerID=8YFLogxK
U2 - 10.1016/S0924-4247(00)00336-8
DO - 10.1016/S0924-4247(00)00336-8
M3 - Article
AN - SCOPUS:0034245591
VL - 85
SP - 116
EP - 123
JO - Sensors and Actuators A: Physical
JF - Sensors and Actuators A: Physical
SN - 0924-4247
IS - 1
ER -