Extraordinary Permittivity Characterization Using 4H-SiC Substrate-Integrated-Waveguide Resonators

Currently, lacking suitable test structures, little data exist for the permittivity of hexagonal materials such as GaN and SiC at millimeter-wave frequencies, especially for the extraordinary permittivity ε
||
as opposed to the ordinary permittivity ε
⊥
. This paper demonstrates for the first time that it is possible to characterize ε
||
of c-axis 4H SiC using on-wafer measurements of substrate-integrated-waveguide resonators. In fact, measurements on eleven resonators yield a relative ε
||
of 10.27 ± 0.03 and a loss tangent tanδ<0.02 over the D band (110-170 GHz). The on-wafer measurements of resonators and other devices fabricated on the same SiC substrate can allow material property to be closely correlated with device performance. The present approach can be extended to materials of other types and orientations.