Na_(0.5)K_(0.5)NbO_(3)/SiO_(2)/Si thin film varactor

摘要

Perfectly c-axis oriented micrometer thick Na_(0.5)K_(0.5)NbO_(3)(NKN) films have been prepared on a thermally grown ultrathin SiO_(2) template layer onto a Si(001) wafer by the pulsed laser deposition technique. A x-ray diffraction θ-2θ scan reveals multiple-cell structuring of single phase NKN film along the polar axis, while films grown onto amorphous ceramic (Corning) glass show a mixture of slightly c-axis oriented NKN and pyrochlore phases. This implies a small amount of SiO_(2) crystallites distributed in an amorphous matrix inherit Si(001) orientation and promotes highly oriented NKN film growth. NKN film dielectric permittivity ε′ was found to vary from 114.0 to 107.2 in the frequency range 1 kHz-I MHz, while the resistivity was on the order of 2.6×10~(10) Ω cm