US5587620A — Tunable thin film acoustic resonators and method …

Claim 1

Independent Claim 220 words

A high-Q, acoustical resonator, comprising: a bottom electrode layer having an ordered structure, a thickness and an acoustical attenuation; a thin-film PZ layer comprising AlN deposited on said lower electrode layer with an ordered structure imparted thereon by said ordered structure of said lower electrode layer, said PZ layer having a top surface and a thickness; and a top electrode layer adjacent to said top surface of said PZ layer, the top electrode layer having a thickness and an acoustical attenuation, wherein: the top electrode layer, the PZ layer, and the bottom electrode layer collectively consitute an acoustic path having a Q, the top electrode layer and the bottom electrode layer each having a thickness relative to the thickness of the PZ layer such that the top electrode layer and the bottom electrode layer collectively constitute such a proportion of the acoustic path that the top electrode layer and the bottom electrode layer having a high acoustical attenuation causes the acoustic path to have a low Q, and both of said top electrode layer and said bottom electrode layer consist essentially of at least one metal chosen from the group consisting of Mo and W to minimize the acoustical attenuation of said top electrode layer and said bottom electrode layer, and thereby to maximize the Q of the acoustical resonator.

Claim 2

Dependent Claim 220 words

A high-Q, acoustical resonator, comprising: a bottom electrode layer having an ordered structure, a thickness and an acoustical attenuation; a thin-film PZ layer comprising AlN deposited on said lower electrode layer with an ordered structure imparted thereon by said ordered structure of said lower electrode layer, said PZ layer having a top surface and a thickness; and a top electrode layer adjacent to said top surface of said PZ layer, the top electrode layer having a thickness and an acoustical attenuation, wherein: the top electrode layer, the PZ layer, and the bottom electrode layer collectively consitute an acoustic path having a Q, the top electrode layer and the bottom electrode layer each having a thickness relative to the thickness of the PZ layer such that the top electrode layer and the bottom electrode layer collectively constitute such a proportion of the acoustic path that the top electrode layer and the bottom electrode layer having a high acoustical attenuation causes the acoustic path to have a low Q, and both of said top electrode layer and said bottom electrode layer consist essentially of at least one metal chosen from the group consisting of Mo and W to minimize the acoustical attenuation of said top electrode layer and said bottom electrode layer, and thereby to maximize the Q of the acoustical resonator.

Claim 3

Dependent Claim 38 words

The acoustical resonator of claim 1 further comprising a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer.

Claim 4

Dependent Claim 30 words

The acoustical resonator of claim 2 wherein the side of said Si 3 N 4 layer remote from said PZ layer comprises a region that is in contact with air.

Claim 5

Dependent Claim 100 words

The acoustical resonator of claim 1, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer, said middle electrode layer constituting part of said acoustic path and consisting essentially of at least one metal chosen from the group consisting of Mo and W; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Claim 6

Dependent Claim 136 words

An acoustical resonator, comprising: a thin-film PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer, said top electrode layer, said PZ layer, and said bottom electrode layer collectively constituting a structure having a resonant frequency, said resonant frequency depending on a temperature of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; and heating means for increasing said temperature of said PZ layer to a predetermined temperature whereat said resonant frequency is equal to a predetermined frequency, said heating means additionally indicating said temperature of said PZ layer.

Claim 7

Dependent Claim 136 words

An acoustical resonator, comprising: a thin-film PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer, said top electrode layer, said PZ layer, and said bottom electrode layer collectively constituting a structure having a resonant frequency, said resonant frequency depending on a temperature of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; and heating means for increasing said temperature of said PZ layer to a predetermined temperature whereat said resonant frequency is equal to a predetermined frequency, said heating means additionally indicating said temperature of said PZ layer.

Claim 8

Dependent Claim 73 words

The acoustical resonator of claim 5, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Claim 9

Dependent Claim 30 words

The acoustical resonator of claim 6 wherein the side of said Si 3 N 4 layer remote from said PZ layer comprises a region that is in contact with air.

Claim 10

Dependent Claim 109 words

An acoustical resonator, comprising: a thin-film PZ layer comprising AlN and having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer, said top electrode layer, said PZ layer, and said bottom electrode layer collectively constituting a structure having a resonant frequency, said resonant frequency depending on a temperature of said PZ layer; and heating means for increasing said temperature of said PZ layer to a predetermined temperature whereat said resonant frequency is equal to a predetermined frequency, said heating means additionally indicating said temperature of said PZ layer.

Claim 11

Dependent Claim 109 words

An acoustical resonator, comprising: a thin-film PZ layer comprising AlN and having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer, said top electrode layer, said PZ layer, and said bottom electrode layer collectively constituting a structure having a resonant frequency, said resonant frequency depending on a temperature of said PZ layer; and heating means for increasing said temperature of said PZ layer to a predetermined temperature whereat said resonant frequency is equal to a predetermined frequency, said heating means additionally indicating said temperature of said PZ layer.

Claim 12

Dependent Claim 73 words

The acoustical resonator of claim 8, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Claim 13

Dependent Claim 92 words

An acoustical resonator, comprising: a PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; and heating means for heating said PZ layer, said heating means comprising a metallic trace in contact with said Si 3 N 4 layer.

Claim 14

Dependent Claim 92 words

An acoustical resonator, comprising: a PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; and heating means for heating said PZ layer, said heating means comprising a metallic trace in contact with said Si 3 N 4 layer.

Claim 15

Dependent Claim 12 words

The acoustical resonator of claim 10, wherein said PZ layer comprises AlN.

Claim 16

Dependent Claim 30 words

The acoustical resonator of claim 10, wherein the side of said Si 3 N 4 layer remote from said PZ layer comprises a region that is in contact with air.

Claim 17

Dependent Claim 24 words

The acoustical resonator of claim 10, wherein said heating means is additionally sandwiched between said PZ layer and said Si 3 N 4 layer.

Claim 18

Dependent Claim 21 words

The acoustical resonator of claim 10, wherein said bottom electrode and said heating means are parts of a common metallization layer.

Claim 19

Dependent Claim 73 words

The acoustical resonator of claim 10, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Claim 20

Dependent Claim 102 words

An acoustical resonator, comprising: a thin-film PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; and an evaporable tuning layer acoustically coupled to said PZ layer, part of said tuning layer being evaporated after fabrication of said acoustical resonator to provide a predetermined resonance frequency for said acoustical resonator, said tuning layer comprising a metallic layer and means for causing a current to pass through said metallic layer thereby causing a portion of said metallic layer to vaporize.

Claim 21

Dependent Claim 102 words

An acoustical resonator, comprising: a thin-film PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; and an evaporable tuning layer acoustically coupled to said PZ layer, part of said tuning layer being evaporated after fabrication of said acoustical resonator to provide a predetermined resonance frequency for said acoustical resonator, said tuning layer comprising a metallic layer and means for causing a current to pass through said metallic layer thereby causing a portion of said metallic layer to vaporize.

Claim 22

Dependent Claim 73 words

The acoustical resonator of claim 16, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Claim 23

Dependent Claim 103 words

An acoustical resonator, comprising: a PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; and a tuning layer in acoustical contact with said PZ layer, the thickness of said tuning layer being adjusted after fabrication of said acoustical resonator to provide a predetermined resonance frequency for said acoustical resonator.

Claim 24

Dependent Claim 103 words

An acoustical resonator, comprising: a PZ layer having top and bottom surfaces; a bottom electrode layer adjacent to said bottom surface of said PZ layer; a layer of Si 3 N 4 adjacent to said bottom electrode layer, said bottom electrode being sandwiched between said layer of Si 3 N 4 and said PZ layer; a top electrode layer adjacent to said top surface of said PZ layer; and a tuning layer in acoustical contact with said PZ layer, the thickness of said tuning layer being adjusted after fabrication of said acoustical resonator to provide a predetermined resonance frequency for said acoustical resonator.

Claim 25

Dependent Claim 30 words

The acoustical resonator of claim 18, wherein the side of said Si 3 N 4 layer remote from said PZ layer comprises a region that is in contact with air.

Claim 26

Dependent Claim 21 words

The acoustical resonator of claim 19 wherein said tuning layer comprises means for depositing a metallic layer on said acoustical resonator.

Claim 27

Dependent Claim 27 words

The acoustical resonator of claim 18, wherein said tuning layer is formed on the side of said Si 3 N 4 layer remote from said PZ layer.

Claim 28

Dependent Claim 36 words

The acoustical resonator of claim 21, wherein said tuning layer comprises a metallic layer and means for causing a current to pass through said metallic layer thereby causing a portion of said metallic layer to vaporize.

Claim 29

Dependent Claim 36 words

The acoustical resonator of claim 18, wherein said tuning layer comprises a metallic layer and means for causing a current to pass through said metallic layer thereby causing a portion of said metallic layer to vaporize.

Claim 30

Dependent Claim 26 words

The acoustical resonator of claim 18, wherein said tuning layer comprises means for depositing a metallic layer on said layer of Si 3 N 4 .

Claim 31

Dependent Claim 73 words

The acoustical resonator of claim 18, wherein: said PZ layer includes an upper PZ layer and a lower PZ layer, said lower PZ layer being deposited on said bottom electrode layer, said top electrode layer being deposited on said upper PZ layer; the acoustical resonator additionally comprises a middle electrode layer deposited on said lower PZ layer; and at least part of said upper PZ layer is deposited on said middle electrode layer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-12-24	2000-06-24	2000-12-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-12-24	2004-06-24	2004-12-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-12-24	2008-06-24	2008-12-24	$7700.00	Window Closed / Lapsed

Tunable thin film acoustic resonators and method for making the same

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