Paul W Stokes

US Patent:

20220416761, Dec 29, 2022

Filed:

Aug 24, 2022

Appl. No.:

17/821906

Inventors:

- Greensboro NC, US
Paul Stokes - Orlando FL, US
Robert Aigner - Ocoee FL, US

International Classification:

H03H 9/13
H01L 41/047
H03H 9/02
H03H 9/17
H01L 41/053
H03H 9/54

Abstract:

Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

US Patent:

20230074357, Mar 9, 2023

Filed:

Nov 10, 2022

Appl. No.:

17/984879

Inventors:

- Greensboro NC, US
Mohammad J. Modarres-Zadeh - Longwood FL, US
Andreas Tag - Altamonte Springs FL, US
Paul Stokes - Orlando FL, US
Robert Aigner - Ocoee FL, US
Gernot Fattinger - Sorrento FL, US

International Classification:

H03H 9/13
H03H 9/17
H03H 9/54
H03H 9/02

Abstract:

Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

US Patent:

20200228089, Jul 16, 2020

Filed:

Jul 30, 2019

Appl. No.:

16/525858

Inventors:

- Greensboro NC, US
Paul Stokes - Orlando FL, US
Robert Aigner - Ocoee FL, US

International Classification:

H03H 9/13
H01L 41/047
H03H 9/02
H01L 41/053
H03H 9/54
H03H 9/17

Abstract:

Bulk acoustic wave (BAW) resonators, and particularly top electrodes with step arrangements for BAW resonators are disclosed. Top electrodes on piezoelectric layers are disclosed that include a border (BO) region with a dual-step arrangement where an inner step and an outer step are formed with increasing heights toward peripheral edges of the top electrode. Dielectric spacer layers may be provided between the outer steps and the piezoelectric layer. Passivation layers are disclosed that extend over the top electrode either to peripheral edges of the piezoelectric layer or that are inset from peripheral edges of the piezoelectric layer. Piezoelectric layers may be arranged with reduced thickness portions in areas that are uncovered by top electrodes. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing weakened BO modes that are shifted farther away from passbands of such BAW resonators.

US Patent:

20170263844, Sep 14, 2017

Filed:

Sep 29, 2016

Appl. No.:

15/279897

Inventors:

- Greensboro NC, US
Paul Stokes - Orlando FL, US
Robert Aigner - Ocoee FL, US

International Classification:

H01L 41/047
H01L 41/29
H03H 9/17

Abstract:

Bulk Acoustic Wave (BAW) resonators with a Border (BO) ring and an inner ring are provided. One BAW resonator includes a bottom electrode, a piezoelectric layer over the bottom electrode, and a top electrode over the piezoelectric layer in which an active region is formed where the top electrode and the bottom electrode overlap. The top electrode includes a BO ring extending about a periphery of the active region and an inner ring inside of and spaced apart from the BO ring. The BO ring is a mass loading of a first portion of the top electrode and the inner ring is a mass unloading of a second portion of the top electrode. Various methods include fabricating a BAW resonator with a top electrode including a mass loading BO ring and a mass unloading inner ring spaced apart from the mass loading BO ring.

US Patent:

20170264267, Sep 14, 2017

Filed:

Sep 29, 2016

Appl. No.:

15/279579

Inventors:

- Greensboro NC, US
Paul Stokes - Orlando FL, US

International Classification:

H03H 9/58
H03H 3/02
H03H 9/13
H03H 9/54
H03H 9/17

Abstract:

A Bulk Acoustic Wave (BAW) resonator with an electrically isolated Border (BO) ring is provided. One BAW resonator includes a bottom electrode and a piezoelectric layer over the bottom electrode and having a top surface with a first portion and second portion about the first portion. The BAW resonator also includes a top electrode over the first portion of the piezoelectric layer and a BO ring including a non-conductive portion that is over the second portion of the piezoelectric layer and adjacent to the piezoelectric layer. The BAW resonator may be a Solidly Mounted BAW (SMR-BAW) resonator or a Film BAW Resonator (FBAR). A radio frequency filter including a ladder configuration with the above BAW resonator as a series BAW resonator and methods for fabricating the above BAW resonator are also provided.

US Patent:

20170170801, Jun 15, 2017

Filed:

Dec 12, 2016

Appl. No.:

15/375846

Inventors:

- Greensboro NC, US
Paul Stokes - Orlando FL, US
Ralph Rothemund - Apopka FL, US
Gernot Fattinger - Sorrento FL, US

International Classification:

H03H 9/02
H03H 3/02
B06B 1/06
H03H 9/17

Abstract:

Bulk Acoustic Wave (BAW) resonators that include a modified outside stack portion and methods for fabricating such BAW resonators are provided. One BAW resonator includes a reflector, a bottom electrode, a piezoelectric layer, and a top electrode. An active region is formed where the top electrode overlaps the bottom electrode and an outside region surrounds the active region. The piezoelectric layer includes a top surface adjacent to the top electrode and a bottom surface adjacent to the bottom electrode. The piezoelectric layer further includes an outside piezoelectric portion in the outside region with a bottom surface in the outside region that is an extension of the bottom surface of the piezoelectric layer, and the outside piezoelectric portion includes an angled sidewall that resides in the outside region and extends from the top surface of the piezoelectric layer to the bottom surface of the outside piezoelectric portion in the outside region.

US Patent:

20170054430, Feb 23, 2017

Filed:

Oct 7, 2015

Appl. No.:

14/877324

Inventors:

- Greensboro NC, US
Alireza Tajic - Winter Springs FL, US
Fabien Dumont - Wekiva Springs FL, US
Paul Stokes - Orlando FL, US
Frida Stromqvist Vetelino - Orlando FL, US

International Classification:

H03H 9/54
H03H 9/17
H03H 3/007

Abstract:

Embodiments of a Bulk Acoustic Wave (BAW) resonator having a high quality factor (Q) and methods of fabrication thereof are disclosed. In some embodiments, a BAW resonator includes a piezoelectric layer, a first electrode on a first surface of the piezoelectric layer, and a second multi-layer electrode on a second surface of the piezoelectric layer opposite the first electrode on the first surface of the piezoelectric layer. In addition, the BAW resonator includes a Border (BO) ring positioned within the second multi-layer electrode around a periphery of an active region of the BAW resonator. The BO ring is either at a position within the second multi-layer electrode between two adjacent layers of the second multi-layer electrode or at a position within the second multi-layer electrode that is adjacent to the piezoelectric layer. In this manner, the quality factor (Q) of the BAW resonator is improved.