A semiconductor device structure is disclosed that includes a wide-bandgap semiconductor portion selected from the group consisting of silicon carbide and the Group III nitrides. An interconnect structure is made to the semiconductor portion, and the interconnect structure includes at least two diffusion barrier layers alternating with two respective high electrical conductivity layers. The diffusion barrier layers have a coefficient of thermal expansion different from and lower than the coefficient of thermal expansion of the high electrical conductivity layers. The difference in the respective coefficients of thermal expansions are large enough to constrain the expansion of the high conductivity layers but less than a difference that would create a strain between adjacent layers that would exceed the bond strength between the layers.