Film bulk acoustic device with integrated tunable and trimmable device
A film bulk acoustic device having integrated trimmable device comprises a FBAR and a integrated tunable and trimmable device being integrated on a common substrate, at least a common electrode or piezoelectric layer. By trimming the integrated trimmable device or the FBAR and alter either the capacitance or inductance of the integrated trimmable device until the film bulk acoustic device having integrated trimmable device achieves the target resonance frequency. By taking advantage of the electrostatic force, the integrated tunable device is capable of providing tuning until the film bulk acoustic device having integrated tunable device achieves the target resonance frequency.
1. A film bulk acoustic device having integrated trimmable device, comprising:
a FBAR being provided on a common substrate and having an upper electrode, a lower electrode and a first piezoelectric layer between the upper electrode and the lower electrode, an equivalent circuit between the upper electrode and the lower electrode having an equivalent inductance; and
an integrated trimmable device, being provided on the common substrate beside the FBAR and having a electrode, the first end of the electrode being provided on the common substrate and connected with the FBAR and being extended to become a second end of the electrode, the shape of trimmable device being spiral or meander shape;
wherein the equivalent inductance of the equivalent circuit of at least one of integrated trimmable device and the FBAR is adjusted by trimming the inductance chosen from the group comprising the second end of the electrode and the upper electrode until the film bulk acoustic device having integrated trimmable device achieves the target resonance frequency.
2. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the electrode of integrated trimmable device is connected with the upper electrode of the FBAR.
3. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the electrode of integrated trimmable device is connected with the lower electrode of the FBAR.
4. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein a gap between the first end and the second is a second piezoelectric layer.
5. The film bulk acoustic device having integrated trimmable device of claim 4 , wherein the first and the second piezoelectric layer are a common piezoelectric layer.
6. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the gap between the first and second end is choosing from the group comprising a dielectric layer and a vacant layer.
7. The film bulk acoustic device having integrated trimmable device of claim 1 , further comprising the means for wafer-level trimming of the integrated trimmable device.
8. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein trimming comprises adding and removing means for altering the geometric shape choosing from the group comprising the second end of the electrode and the upper electrode.
9. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the inductance of the integrated trimmable device is measured across the first end of the electrode and the borderline between the electrode and the FBAR.
10. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the equivalent inductance of the equivalent circuit of the FBAR is measured across the upper and lower electrode.
11. The film bulk acoustic device having integrated trimmable device of claim 1 , wherein the FBAR may be fabricated by front-side etching as well as back-side etching.