The present invention provides a composite structure having a supporting
substrate between a piezoelectric substrate and a compensation layer. The
materials used to form the piezoelectric substrate and the compensation
layer in isolation, have higher thermal coefficients of expansion (TCE)
relative to the TCE of the materials forming the supporting substrate.
Once the composite structure is created, the piezoelectric substrate and
compensation layer tend to expand and contract in a similar manner as
temperature changes. The expansion and contraction forces applied to the
supporting substrate by the piezoelectric substrate due to temperature
changes are substantially countered by similar opposing forces applied by
the compensation layer, resulting in the opposing forces substantially
counteracting one another. Due to the counteraction, the composite
structure resists bending or warping, reducing expansion and contraction
and increasing stress of the piezoelectric substrate, and thus reducing
the effective TCE and TCF of the piezoelectric substrate.