MEMS component having AlN and Sc and method for manufacturing a MEMS component

#This patent application is a national phase filing under section 371 of PCT/EP2012/076723, filed Dec. 21, 2012, which is incorporated herein by reference in its entirety.

#The present invention refers to MEMS components, e.g., BAW components or piezoelectric switches, and to methods for manufacturing such components.

#The present trend towards miniaturization of mobile communication devices demands for smaller electric and electro-acoustic components. BAW (BAW=bulk acoustic wave) components can be used in RF filters, e.g., in duplexers in front-end modules of mobile communication devices. A duplexer usually comprises a TX (transmission) and an RX (reception) filter. The TX filter and the RX filter are band-pass filters with adjacent but different pass bands. An important factor determining the pass band of a BAW band-pass filter is the thickness of piezoelectric material arranged between two electrode layers of a resonator of the filter and the mass loading of a resonator.

#Examples of MEMS components and their manufacturing methods and the respective working principles are shown in the schematic figures.

#FIG. 1 shows a basic MEMS component with a piezoelectric layer PL1 between two electrode layers LE, UE;

#FIG. 2 shows a MEMS component with two BAW resonator stacks;

#FIG. 1 shows a MEMS component MC comprising a first piezoelectric layer PL1 between a lower electrode LE and an upper electrode UE. The first piezoelectric layer PL1 comprises the first piezoelectric material with AlN and Sc. This allows for a high-quality MEMS component with a structured first piezoelectric layer PL1, as methods for structuring Sc and AlN comprising piezoelectric material were found.

#FIG. 2 shows a MEMS component MC where a first BAW resonator BAWR1 is arranged next to a second BAW resonator BAWR2. Both resonators can be arranged on or above a carrier substrate CS. Both resonators comprise a lower electrode LE and an upper electrode UE. At least the first BAW resonator BAWR1 comprises a first piezoelectric material. Piezoelectric layers PL1, PL2 and the electrodes LE, UE establish a first lamination LS1 and a second lamination LS2 of the resonator, respectively, in which an acoustic wave is excited when an RF signal is applied to the respective electrodes. The piezoelectric layer PL2 of the second BAW resonator BAWR2 is thicker than the piezoelectiric layer PL1 of the first resonator BAWR1. Thus, both resonators have different resonance frequencies although they can be manufactured by means of easy-to-perform manufacturing steps one next to the other on or above a common carrier substrate CS.

#FIG. 3 shows main components of a BAW component BAWC where mainly the top electrode is omitted. Two resonator stacks are arranged on respective acoustic mirrors AM. The acoustic minors AM comprise a layer system with alternating high and low acoustic impedance. The acoustic minor AM confines acoustic energy and allows establishing a resonance mode of the respective resonator.