The invention provides a cavity type
bulk acoustic wave resonator without preparing a sacrificial layer and a preparation method of the cavity type
bulk acoustic wave resonator. The method comprises the following steps that a piezoelectric
single crystal wafer which is subjected to
ion implantation and provided with a bottom
electrode is taken, a cavity is formed in the side, provided with the bottom
electrode, of the piezoelectric
single crystal wafer, then a substrate is taken, and the substrate and the side, provided with the cavity, of the piezoelectric
single crystal wafer are bonded; andheat treatment is carried out on the bonded
intermediate product to strip the film of the piezoelectric single
crystal wafer, and then a top
electrode is produced on one stripped side of the piezoelectric single
crystal wafer to obtain the cavity type
bulk acoustic wave resonator. According to the preparation method of the cavity type bulk acoustic resonator without the need of preparing the sacrificial layer, the sacrificial layer does not need to be grown,
etching and
trepanning are not carried out on the thin film, the
mechanical strength of the device is improved, and damage to the thin film is not likely to be generated; the cavity structure is formed before film formation, the rate of finished products is high, residues left by
etching after film formation do not exist, and the influence of incomplete release on the device does not need to be considered.