Integration of microwave phase shifter with BST varactor onto TiO2/Si wafer

Abstract

A BST ferroelectric thin-film microwave phase shifter with interdigital capacitors on TiO2/Si substrate is presented. The interdigital capacitors have 230 mu m signal width, 100 pm signal to ground gap, and 10 mu m finger gap. The device, with phase shifts of 142 degrees and FoM of 107.3 degrees/dB applied voltage of 50 V at 16 GHz, has been realised. The TiO2 buffer layer grown by ALD enables successful integration of BST-based microwave tunable devices with Si wafer.