Highly transparent PZT capacitors on glass obtained by layer transfer process

Abstract

Transparent ITO/PZT/ITO capacitors were fabricated on 200 mm glass substrate. The PZT films of 1 µm and 2 µm thickness were first grown on platinized Si wafer by sol-gel method, and then transferred onto glass substrate together with ITO electrodes following an innovative process. The obtained PZT based stacks on glass show an average transmission of about 70 % in the visible range. PZT films keep their preferred (100) orientation after transfer process. The capacitors exhibit ferroelectric, dielectric and piezoelectric properties comparable to standard non-transparent PZT films with metal electrodes. Transverse piezoelectric coefficient e31,f as high as 16 C/m² was measured for both PZT film thicknesses. This proof of concept opens the way to the fabrication of transparent piezoelectric actuators on glass for high performances haptic devices, as well as for other emerging applications like self-cleaning or functionalization of smart windows.

Active optical phased array integrated within a micro-cantilever

“…The TPMs are electrically connected to probe contacts on the fixed part of the chip via tungsten vias and a single layer of aluminum tracks. Following the completion of the photonic wafer fabrication, a PZT layer, prepared separately (so as not to exceed the thermal budget of the photonics technology) using a sol-gel technique on a 200 mm silicon wafer, is transferred to the photonic circuit using Au/Au wafer-to-wafer bonding 35 , 36 . The donor substrate is removed and the PZT layer is patterned 36 , 37 before the creation of electrical tracks and surface contact pads in order to apply a vertical electric field (in y ).…”

“…Following the completion of the photonic wafer fabrication, a PZT layer, prepared separately (so as not to exceed the thermal budget of the photonics technology) using a sol-gel technique on a 200 mm silicon wafer, is transferred to the photonic circuit using Au/Au wafer-to-wafer bonding 35 , 36 . The donor substrate is removed and the PZT layer is patterned 36 , 37 before the creation of electrical tracks and surface contact pads in order to apply a vertical electric field (in y ). Finally the cantilever was created by selectively etching the SiO 2 around and beneath the desired cantilever shape (more details in the methods section).…”

Piezoelectric Layer Transfer Process for MEMS

“…The technological process that allows transferring of piezoelectric PZT film stacks from silicon substrate to any other substrate is depicted in Figure 1 [1]. High quality PZT film is first grown on platinized Si wafer.…”

Active optical phased array integrated within a micro-cantilever

“…The TPMs are electrically connected to probe contacts on the fixed part of the chip via tungsten vias and a single layer of aluminium tracks. Following the completion of the photonic wafer fabrication, a PZT layer, prepared using a sol-gel technique on a 200mm silicon wafer, is transferred to the photonic circuit using Au/Au wafer-to-wafer bonding [32,33]. The donor substrate is removed and the PZT layer is patterned [33,34] before electrical tracks and surface contact pads were created in order to apply a vertical electric field (in y).…”

“…Following the completion of the photonic wafer fabrication, a PZT layer, prepared using a sol-gel technique on a 200mm silicon wafer, is transferred to the photonic circuit using Au/Au wafer-to-wafer bonding [32,33]. The donor substrate is removed and the PZT layer is patterned [33,34] before electrical tracks and surface contact pads were created in order to apply a vertical electric field (in y). Finally the cantilever was created by selectively etching the SiO2 around and beneath the desired cantilever shape (more details in the methods section).…”