Bulk acoustic wave (baw) device having roughened bottom side
AssigneeTexas Instruments Incorporated
InventorsSTUART M. JACOBSEN, BRIAN GOODLIN
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Abstract
A bulk acoustic wave (BAW) resonator includes a substrate having a top side surface and a bottom side surface. A Bragg mirror is on the top side surface of the substrate. A bottom electrode layer is on the Bragg mirror, and a piezoelectric layer is on the bottom electrode layer. A top dielectric layer is on the piezoelectric layer, and a top electrode layer is on the top dielectric layer. The bottom side surface of the substrate has a surface roughness of at least 1 μm root mean square (RMS).
Claims19
A method of fabricating a bulk acoustic wave (BAW) resonator, comprising:
- providing a Bragg mirror on a top side surface of a substrate having a bottom side surface opposite said top side surface;
- forming a bottom electrode layer on said Bragg mirror;
- forming a piezoelectric layer on said bottom electrode layer;
- forming a top dielectric layer on said piezoelectric layer;
- forming a top electrode layer on said top dielectric layer, and
- roughening said bottom side surface to provide a final surface roughness of at least 1 μm root mean square (RMS), wherein said method excludes a polishing step(s) after said roughening.
A bulk acoustic wave (BAW) resonator, comprising:
- a substrate having a top side surface and a bottom side surface;
- a Bragg mirror on said top side surface of said substrate;
- a bottom electrode layer on said Bragg mirror;
- a piezoelectric layer on said bottom electrode layer;
- a top dielectric layer on said piezoelectric layer, and
- a top electrode layer on said top dielectric layer,
- wherein said bottom side surface has a surface roughness of at least 1 μm root mean square (RMS).
An oscillator, comprising:
- a bulk acoustic wave (BAW) resonator, comprising:
- a substrate having a top side surface and a bottom side surface;
- a Bragg mirror on said top side surface of said substrate;
- a bottom electrode layer on said Bragg mirror;
- a piezoelectric layer on said bottom electrode layer;
- a top dielectric layer on said piezoelectric layer, and
- a top electrode layer on said top dielectric layer,
- wherein said bottom side surface has a surface roughness of at least 1 μm root mean square (RMS), and
- an oscillator core coupled to said top electrode layer and to said bottom electrode layer to provide a signal input to said oscillator core.
Dependencies are inferred from the claim text.