posted on 2022-02-04, 15:06authored byMartin Lee, Martin P. Robin, Ruben H. Guis, Ulderico Filippozzi, Dong Hoon Shin, Thierry C. van Thiel, Stijn P. Paardekooper, Johannes R. Renshof, Herre S. J. van der Zant, Andrea D. Caviglia, Gerard J. Verbiest, Peter G. Steeneken
Although 2D materials
hold great potential for next-generation
pressure sensors, recent studies revealed that gases permeate along
the membrane-surface interface, necessitating additional sealing procedures.
In this work, we demonstrate the use of free-standing complex oxides
as self-sealing membranes that allow the reference cavity beneath
to be sealed by a simple anneal. To test the hermeticity, we study
the gas permeation time constants in nanomechanical resonators made
from SrRuO3 and SrTiO3 membranes suspended over
SiO2/Si cavities which show an improvement up to 4 orders
of magnitude in the permeation time constant after annealing the devices.
Similar devices fabricated on Si3N4/Si do not
show such improvements, suggesting that the adhesion increase over
SiO2 is mediated by oxygen bonds that are formed at the
SiO2/complex oxide interface during the self-sealing anneal.
Picosecond ultrasonics measurements confirm the improvement in the
adhesion by 70% after annealing.