BAW RESONATOR WITH IMPROVED CRYSTALLINE QUALITY, RF FILTER, MULTIPLEXER AND METHOD OF MANUFACTURING

摘要

An improved BAW resonator is provided. The resonator has a compensation layer (CL) between the bottom electrode (BE) and the piezoelectric layer (PL) to compensate lattice mismatch. The compensation layer (CL) may comprise GaN, InN, InGaN and the piezoelectric layer (PL) epitaxial AIN or AIScN. The compensation layer may have several sublayers (SL1,...SL6) with stepwise or continuously varying composition and content of gallium and indium. A further layer for compensating lattice mismatch may be present between piezoelectric (PL) layer and top electrode (TE).