The lower electrode 102 is formed over an upper portion of the substrate 101, and is separated by a predetermined distance from the upper portion of the substrate 101. For example, the lower electrode 102 may be made of molybdenum (Mo), ruthenium (Ru), tungsten (W), and/or other conductive materials known to one of ordinary skill in the art. The lower electrode 102 may be used as an input electrode to inject an electrical signal, such as a radio frequency (RF) signal, into the piezoelectric layer 104, and/or as an output electrode to output an electrical signal from the piezoelectric layer 104. For example, if the lower electrode 102 is an input electrode, the upper electrode 105 is an output electrode. If the lower electrode 102 is an output electrode, the upper electrode 105 is an input electrode.

A cavity 103 is formed between the lower electrode 102 and the substrate 101. Therefore, the lower electrode 102 is separated from the substrate 101 by as much as the cavity 103.

The upper electrode 105 is formed on an upper portion of the piezoelectric layer 104. For example, the upper electrode 105 may be formed by vapor depositing Mo, Ru, W, and/or other conductive materials known to one of ordinary skill in the art, on the upper portion of the piezoelectric layer 104. The upper electrode 105 may be used as an input electrode to inject an electrical signal, such as an RF signal, into the piezoelectric layer 104, and/or as an output electrode to output an electrical signal from the piezoelectric layer 104.