CN-111095794-B - Surface acoustic wave device

Abstract

A surface acoustic wave (surface acoustic wave, SAW) device includes a piezoelectric layer, a high acoustic speed layer coupled to the piezoelectric layer, and at least one transducer. The SAW device may include multiple graphene layers in at least one electrode of the transducer and multiple graphene layers in a conductive layer coupled to the piezoelectric layer.

Inventors

• CHEN ZHUOHUI

Assignees

• 华为技术有限公司

Dates

Publication Date

20260505

Application Date

20180921

Priority Date

20170922

Claims (4)

1. 1. A surface acoustic wave (surface acoustic wave, SAW) device, comprising: A piezoelectric layer; a high acoustic velocity layer coupled to the piezoelectric layer on a first surface of the piezoelectric layer, and At least one transducer between the piezoelectric layer and the high acoustic velocity layer, wherein the at least one transducer comprises an electrode using a first multi-layer graphene layer, the electrode having a thickness of substantially 0λ comprising graphene of 3-5 atomic layers of the first multi-layer graphene layer, the at least one transducer for propagating a surface acoustic wave having an operating wavelength (λ) along the piezoelectric layer; The SAW device further includes a conductive layer coupled to a second surface of the piezoelectric layer, the second surface of the piezoelectric layer opposite the first surface of the piezoelectric layer, the conductive layer being a metal layer coupled to a second multi-layer graphene layer, the second multi-layer graphene layer being coupled on top of the metal layer, the metal layer having a thickness of 0.01λ, the second multi-layer graphene layer comprising graphene of 3-5 atomic layers.
2. 2. The SAW device of claim 1, wherein said at least one transducer is embedded in said piezoelectric layer.
3. 3. The SAW device of claim 1, wherein said at least one transducer is embedded in said high acoustic velocity layer.
4. 4. A surface acoustic wave (surface acoustic wave, SAW) device, comprising: A piezoelectric layer; a high acoustic velocity layer coupled to the piezoelectric layer on a first surface of the piezoelectric layer; the piezoelectric layer and the high acoustic velocity layer being coupled to each other by a conductive layer, and At least one transducer coupled to a second surface of the piezoelectric layer opposite the first surface of the piezoelectric layer, wherein the at least one transducer comprises an electrode comprising a first multi-layer graphene layer coupled to a first metal layer, the first multi-layer graphene layer being coupled on top of the first metal layer, the first multi-layer graphene layer having a thickness of substantially 0λ, the thickness of substantially 0λ comprising graphene having 3-5 atomic layers of the first multi-layer graphene layer, the first metal layer having a thickness of 0.08λ, the at least one transducer being configured to propagate surface acoustic waves having an operating wavelength (λ) along the piezoelectric layer; the conductive layer is a second multi-layer graphene layer comprising 3-5 atomic layers of graphene.

Description

Surface acoustic wave device Technical Field The present application relates to a surface acoustic wave (surface acoustic wave, SAW) device. In various examples, the present application relates to any or all of SAW filters, resonators, and diplexers with improved electromechanical coupling and higher power durability. Background In communication systems (terminal and base station infrastructure), surface acoustic wave (surface acoustic wave, SAW) filters and resonators are widely used. For next generation 5G New Radio (NR) wireless communications, there is a growing need for at least one of higher operating frequencies, lower insertion loss, higher transmit power, and greater channel bandwidth. New piezoelectric materials or structures are needed to support the ever-increasing demand for higher frequencies and greater channel bandwidths. SAW filters generally require a high electromechanical coupling coefficient. As the transmit power increases, the durability of the SAW device decreases. Thus, improving durability may help to increase operating frequency and transmit power. Scandium-doped aluminum nitride (Scandium-doped aluminum nitride, scAlN) films are of great interest because of their good piezoelectricity, high thermal conductivity, and relatively high acoustic velocity. Bridge et al describe this structure in the context of a "high Q surface acoustic wave resonator in the 2-3GHz range using ScAlN-single crystal diamond structure". (conference: 2012IEEE International ultrasound Association (International Ultrasonics Symposium, IUS)). Similarly, zhang Qiaozhen et al also describe another such structure in "surface acoustic wave propagation characteristics of ScAlN/diamond structure with buried electrode" one. (2014, p.271-274, 2014). These structures have been discussed but are not sufficient to solve the specific problems described herein. Disclosure of Invention In various examples described herein, multiple graphene layers are added to SAW devices to achieve high efficiency electromechanical coupling coefficients, high operating frequencies, and high power durability. In some aspects, a surface acoustic wave (surface acoustic wave, SAW) device is described. The SAW device includes a piezoelectric layer, a high acoustic speed layer coupled to the piezoelectric layer on a first surface of the piezoelectric layer, and at least one transducer between the piezoelectric layer and the high acoustic speed layer. The at least one transducer includes a first multi-layer graphene layer. The at least one transducer is configured to propagate a surface acoustic wave having an operating wavelength (λ) along the piezoelectric layer. In any of the above aspects/embodiments, the first multi-layer graphene layer may comprise 2-10 atomic layers of graphene. In any of the above aspects/embodiments, the first multi-layer graphene layer may comprise 3-5 atomic layers of graphene. In any of the above aspects/embodiments, the SAW device may include a conductive layer coupled to a second surface of the piezoelectric layer opposite the first surface of the piezoelectric layer. In any of the above aspects/embodiments, the conductive layer may be a second multi-layer graphene layer coupled with a metal layer. In any of the above aspects/embodiments, the second multi-layer graphene layer may comprise 3-10 atomic layers of graphene. In any of the above aspects/embodiments, the conductive layer may be a second multi-layer graphene layer. In any of the above aspects/embodiments, the second multi-layer graphene layer may comprise 3-10 atomic layers of graphene. In any of the above aspects/embodiments, the transducer may comprise the first multi-layer graphene layer coupled with a metal layer. In any of the above aspects/embodiments, the first multi-layer graphene layer may comprise 3-10 atomic layers of graphene. In any of the above aspects/embodiments, the at least one transducer may be embedded in the piezoelectric layer. In any of the above aspects/embodiments, the at least one transducer may be embedded in the high acoustic velocity layer. In some aspects, a surface acoustic wave (surface acoustic wave, SAW) device is described. The SAW device includes a piezoelectric layer and a high acoustic velocity layer coupled to the piezoelectric layer on a first surface of the piezoelectric layer. The piezoelectric layer and the high acoustic velocity layer are coupled to each other by a conductive layer. The SAW device further includes at least one transducer coupled to a second surface of the piezoelectric layer opposite the first surface of the piezoelectric layer. The at least one transducer includes a first multi-layer graphene layer coupled with a metal layer. The at least one transducer is configured to propagate a surface acoustic wave having an operating wavelength (λ) along the piezoelectric layer. In any of the above aspects/embodiments, the conductive layer may be a second multi-layer graphene layer. In any of the above asp