Title :
New manufacturing method for capacitive ultrasonic transducers with monocrystalline membrane
Author :
Rev, P. ; Salhi, M. ; Giroud, S. ; Robert, P. ; Lagahe-Blanchard, C. ; CIatot, S. ; Ballandras, S.
Author_Institution :
CEA-LETI, Grenoble
Abstract :
A new method to manufacture Capacitive Micromachined Ultrasonic Transducers (eMUT) combining a wafer bonding and a sacrificial layer processes is introduced. Devices with monocrystalline silicon membranes over a polysilicon electrode have been manufactured. The process is highly reliable and shows an excellent homogeneity all over the 200 mm wafer. From impedance measurements in air of a monocell test device biased under 140 V, a resonance at 8.0 MHz and an electromechanical coupling coefficient of 45% have been found. Underwater pulse-echo experiments are presented demonstrating a large bandwidth of the device of about 130%.
Keywords :
capacitive sensors; elemental semiconductors; membranes; micromachining; microsensors; semiconductor device manufacture; silicon; ultrasonic transducers; wafer bonding; capacitive micromachined ultrasonic transducers; electromechanical coupling coefficient; frequency 8.0 MHz; manufacturing method; monocell test device; monocrystalline silicon membrane; polysilicon electrode; sacrificial layer processes; size 200 mm; underwater pulse-echo experiments; voltage 140 V; wafer bonding; Bandwidth; Biomembranes; Electrodes; Impedance measurement; Manufacturing processes; Resonance; Silicon; Testing; Ultrasonic transducers; Wafer bonding;
Conference_Titel :
Micro Electro Mechanical Systems, 2007. MEMS. IEEE 20th International Conference on
Conference_Location :
Hyogo
Print_ISBN :
978-1-4244-0950-1
DOI :
10.1109/MEMSYS.2007.4432987
