Multiphysics simulation of a Scanning Microwave Microscope:
A joint electromagnetic and thermal analysis
Tamara Monti
National Center for Industrial Microwave Processing (NCIMP) -
University Of Nottingham
Scanning Microwave Microscopy (SMM) is considered as one of the
most promising
techniques for characterizing samples down to the nanoscale and
for quantitative
determination of dielectric properties.
The microscope works through near-field interaction of
microwaves with the sample under
analysis; the rapid decay of the field at the end of a sharp
emitter ensures that the interaction
is extremely localized and the resolution of the microscope is
exceptionally high (nanometric
scale). Usually the energy transferred to samples is negligible
so that the SMM is usually
considered as a non-destructive technique.
In this work, a COMSOL multiphysics simulation of a Scanning
Tunneling Microscope
(STM)-aided SMM is presented. In particular, the joint
electromagnetic and heating transfer
simulations are performed. The different thermal behavior of two
typical samples (HOPG and
CuO) is shown, after a 5 minutes exposure to the microwave
radiation.
The results demonstrate that the maximum thermal gradient on the
samples under study is
below 2 degrees, even with an input power of 1W (6 order of
magnitude higher than the
typical power in use), making the technique suitable for
non-destructive analyses.
Furthermore, the multiphysics model can be efficiently applied
to the understanding of
etching phenomena occurred during SMM applications on
non-conventional samples, already
reported in past works.
