# US 2018/0323767 A1 · Film bulk acoustic resonator (fbar) devices for high frequency rf filters

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- Number: US 2018/0323767 A1
- Document ID: US20180323767A1
- Status: Published application
- Kind: A1
- Application number: 15/773,016
- Filed: 2015-12-04
- Published: 2018-11-08
- Earliest claimed: 2015-12-04
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: HAN WUI THEN; SANSAPTAK DASGUPTA; MARKO RADOSAVLJEVIC
- Web page: https://patentgrep.com/patent/US20180323767A1

## CPC

- H03H 9/173: {Air-gaps}
- H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence)
- H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles}
- H03H 9/13: for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145)
- H03H 9/174: {Membranes}
- H03H 9/562: {comprising a ceramic piezoelectric layer}
- H03H 2003/021: {the resonators or networks being of the air-gap type}
- H03H 2003/023: {the resonators or networks being of the membrane type}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

Techniques are disclosed for forming high frequency film bulk acoustic resonator (FBAR) devices using epitaxially grown piezoelectric films. In some cases, the piezoelectric layer of the FBAR may be an epitaxial III-V layer such as an aluminum nitride (AlN) or other group III material-nitride (III-N) compound film grown as a part of a III-V material stack, although any other suitable piezoelectric materials can be used. Use of an epitaxial piezoelectric layer in an FBAR device provides numerous benefits, such as being able to achieve films that are thinner and higher quality compared to sputtered films, for example. The higher quality piezoelectric film results in higher piezoelectric coupling coefficients, which leads to higher Q-factor of RF filters including such FBAR devices. Therefore, the FBAR devices can be included in RF filters to enable filtering high frequencies of greater than 3 GHz, which can be used for 5G wireless standards, for example.

## Claims

### Claim 1

An integrated circuit including at least one resonator device, the integrated circuit comprising:
a bottom electrode including one or more metals;
a bottom cavity below the bottom electrode;
a top electrode above the bottom electrode, the top electrode including one or more metals;
a top cavity above the top electrode; and
layer including semiconductor material, the layer between the bottom electrode and the top electrode, the layer having a maximum thickness of less than 1 micron and crystallinity characterized by an X-ray rocking curve full width at half maximum (FWHM) of less than 1.5 degrees.

### Claim 2 (depends on 1)

The integrated circuit of claim 1, wherein the layer includes nitrogen and at least one of aluminum, gallium, or indium.

### Claim 3 (depends on 1)

The integrated circuit of claim 1, wherein the layer includes aluminum and nitrogen.

### Claim 4 (depends on 1)

The integrated circuit of claim 1, wherein the layer has a maximum thickness of less than 500 nanometers.

### Claim 5 (depends on 1)

The integrated circuit of claim 1, wherein the layer crystallinity is characterized by an X-ray rocking curve FWHM of less than 1 degree.

### Claim 6 (depends on 1)

The integrated circuit of claim 1, further comprising an additional layer between the bottom electrode and the layer, the additional layer including gallium and nitrogen.

### Claim 7 (depends on 1)

The integrated circuit of claim 1, further comprising an additional layer between the bottom electrode and the layer, the additional layer including aluminum and nitrogen.

### Claim 8 (depends on 1)

The integrated circuit of claim 1, wherein the bottom cavity is between the bottom electrode and a bulk silicon substrate.

### Claim 9 (depends on 1)

The integrated circuit of claim 1, wherein the layer has a maximum thickness of less than 200 nanometers and an X-ray rocking curve FWHM of less than 0.5 degrees.

### Claim 10 (depends on 1)

The integrated circuit of claim 1, wherein the bottom electrode or the top electrode, or both the bottom and top electrodes, includes a multilayer structure including a dielectric layer between two metal layers.

### Claim 11 (depends on 1)

The integrated circuit of claim 1, further comprising a first interconnect in direct contact with the top electrode, and a second interconnect that extends through the layer.

### Claim 12 (depends on 11)

The integrated circuit of claim 11, wherein the second interconnect is not in direct contact with the bottom electrode.

### Claim 13 (depends on 11)

The integrated circuit of claim 11, wherein the second interconnect is in direct contact with the bottom electrode.

### Claim 14 (depends on 1)

The integrated circuit of claim 1, further comprising a radio frequency (RF) filter that includes the at least one resonator device.

### Claim 15 (depends on 14)

The integrated circuit of claim 14, wherein the RF filter is configured to filter frequencies of greater than 3 GHz.

### Claim 16 (depends on 1)

A computing system comprising the integrated circuit of claim 1.

### Claim 17

An integrated circuit including at least one film bulk acoustic resonator (FBAR) device, the integrated circuit comprising:
a substrate;
a bottom electrode above the substrate;
a cavity between the substrate and the bottom electrode;
a first layer above the bottom electrode, the first layer including gallium and nitrogen;
a second layer above the first layer, the second layer including nitrogen and at least one of aluminum, gallium, or indium; and
a top electrode above the second layer.

### Claim 18 (depends on 17)

The integrated circuit of claim 17, wherein the at least one of aluminum, gallium, or indium included in the second layer is aluminum.

### Claim 19 (depends on 17)

The integrated circuit of claim 17, wherein the second layer has a maximum thickness of less than 1 micron and crystallinity characterized by an X-ray rocking curve full width at half maximum (FWHM) of less than 1.5 degrees.

### Claim 20 (depends on 17)

The integrated circuit of claim 17, the second layer is directly on the first layer, and the top electrode is directly on the second layer.

### Claim at position 21

21-25. (canceled)