Layer structures for RF filters fabricated using rare earth oxides and epitaxial aluminum nitride

Patent metadata

Field	Value
Publication number	US-10566944-B2
Application number	US-201816126840-A
Country	US
Kind code	B2
Filing date	Sep 10, 2018
Priority date	Nov 13, 2015
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

Layer structures for RF filters can be fabricated using rare earth oxides and epitaxial aluminum nitride, and methods for growing the layer structures. A layer structure can include an epitaxial crystalline rare earth oxide (REO) layer over a substrate, a first epitaxial electrode layer over the crystalline REO layer, and an epitaxial piezoelectric layer over the first epitaxial electrode layer. The layer structure can further include a second electrode layer over the epitaxial piezoelectric layer. The first electrode layer can include an epitaxial metal. The epitaxial metal can be single-crystal. The first electrode layer can include one or more of a rare earth pnictide, and a rare earth silicide (RESi).

First claim

What is claimed is:

1. A layered structure, comprising:
a substrate;
a crystalline rare earth oxide (REO) layer over the substrate;
an electrode layer grown directly over the crystalline REO layer;
a buffer region over the electrode layer, wherein the buffer region comprises a piezoelectric layer and a rare earth containing layer over the piezoelectric layer; and
one or more device layers over the buffer region.

2. The layered structure of claim 1 , wherein the one or more device layers comprise another electrode layer.

3. The layered structure of claim 1 , wherein the buffer region comprises one or more repetitions of a III-N or rare earth III-N layer.

4. The layered structure of claim 1 , wherein the one or more device layers comprise one or more III-N or RE-III-N layers.

5. The layered structure of claim 1 , wherein a thickness of the crystalline REO layer is chosen to compensate for resonance frequency drift of the one or more device layers.

6. The layered structure of claim 1 , wherein the one or more device layers comprise a second piezoelectric layer.

7. The layered structure of claim 6 , wherein the one or more device layers further comprise another crystalline REO layer over the second piezoelectric layer.

8. The layered structure of claim 6 , wherein the one or more device layers further comprise a porous silicon layer over the second piezoelectric layer.

9. The layered structure of claim 1 , further comprising:
a buffer layer over the one or more device layers, wherein the buffer layer comprises one or more of a III-N layer and a rare earth-III-N layer.

10. The layered structure of claim 1 , wherein the piezoelectric layer comprises an aluminum scandium nitride.

Assignees

• Iqe Plc

Inventors

• Pelzel Rodney
• Dargis Rytis
• Clark Andrew
• Williams Howard
• Chin Patrick
• Lebby Michael

Classifications

• H03H3/08

  for the manufacture of resonators or networks using surface acoustic waves · CPC title

• H03H2001/0064

  comprising semiconductor material · CPC title

• H03H2003/025

  the resonators or networks comprising an acoustic mirror · CPC title

• H03H3/02

  for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) · CPC title

• H03H2001/0085

  Multilayer, e.g. LTCC, HTCC, green sheets · CPC title