Structural and dielectric properties of epitaxial Ba1-xSrxTiO3/Bi4Ti3O12/ZrO2 heterostructures grown on silicon

We report on the dielectric properties of an epitaxial heterostructure comp rised of Ba1-xSrxTiO3, Bi4Ti3O12, and (ZrO2)(0.91)(Y2O3)(0.09) grown on sil icon substrates for potential use in microwave devices. Careful x-ray analy sis indicates crystallographic alignment of all layers and transmission ele ctron microscopy and Auger analysis reveals high quality epitaxy with minim al interdiffusion. The viability of using such heterostructures in actual m icrowave devices was assessed by incorporating the films in a coupled micro stripline phase shifter design. The phase shifter devices, operating in the Ku band, had losses of less than 4 dB with a maximum phase shift of nearly 40 degrees at 40 V. We compare this performance with a (Ba, Sr)TIO3/MgO ph ase shifter. These results presented represent significant progress towards integrating ferroelectric films with conventional silicon technology. (C) 2000 American Institute of Physics. [S0003-6951(00)03336-2].