1. A filter device, comprising:
two or more surface acoustic wave resonators, including at least a first shunt resonator, formed on a surface of a substrate; and
a ground conductor formed on the surface of the substrate, the ground conductor extending from the first shunt resonator to a ground pad, at least a portion of an edge of the ground conductor shaped as a plurality of serrations.
2. The filter device of claim 1, wherein the plurality of serrations are configured to scatter incident surface acoustic waves to reduce acoustic coupling between at least some of the two or more surface acoustic wave resonators.
3. The filter device of claim 1, wherein one or more of the plurality of serrations are triangular.
4. A filter device formed on a surface of a substrate, comprising:
a plurality of surface acoustic wave series resonators;
a plurality of surface acoustic wave shunt resonators;
an input pad, an output pad, and one or more ground pads;
a plurality of signal conductors that interconnect the input pad, the output pad, the plurality of surface acoustic wave series resonators and a first end of each of plurality of surface acoustic wave shunt resonators; and
one or more ground conductors that respectively connect each of the one or more ground pads with a second end of at least one of the plurality of surface acoustic wave shunt resonators, wherein
at least a portion of an edge of at least one of the one or more ground conductors is shaped as a plurality of serrations, and
the one or more ground conductors, in aggregate, cover more than 50% of a useable area of the substrate not occupied by the series resonators, the shunt resonators, and the signal conductors.
5. The filter device of claim 4, wherein:
the one or more ground pads is a plurality of ground pads; and
the one or more ground conductor is a plurality of ground conductors, each ground conductor connecting a corresponding one of the plurality of ground pads to a second end of one or more of the plurality of surface acoustic wave shunt resonators.
6. The filter device of claim 5, wherein at least a portion of respective edges of two or more of the plurality of ground conductors are shaped as a plurality of serrations.
7. The filter device of claim 5, wherein at least a portion of respective edges of every one of the plurality of ground conductors are shaped as a plurality of serrations.
8. The filter device of claim 5, wherein each of the plurality of ground pads is electrically isolated from all other ground pads from the plurality of ground pads.
9. (canceled)
10. The filter device of claim 4, wherein the one or more ground conductors, in aggregate, cover at least 70% of the useable area of the substrate not occupied by the series resonators, the shunt resonators, and the signal conductors.
11. A duplexer device formed on a surface of a substrate, comprising:
an input pad, an antenna pad, an output pad, and at least one ground pad;
a transmit filter coupled between the input pad and the antenna pad, the transmit filter comprising:
a plurality of transmit surface acoustic wave shunt resonators;
one or more transmit ground pads; and
one or more transmit ground conductors respectively connecting each of the transmit ground pads to one or more of the plurality of transmit surface acoustic wave shunt resonators, at least a portion of edges of the transmit ground conductors shaped as a plurality of serrations; and
a receive filter coupled between the antenna pad and the output pad, the receive filter comprising:
a plurality of receive surface acoustic wave shunt resonators;
one or more receive ground pads; and
one or more receive ground conductors respectively connecting each of the receive ground pads to one or more of the plurality of receive surface acoustic wave shunt resonators, at least a portion of edges of the receive ground conductors shaped as a plurality of serrations, wherein
the one or more receive ground conductors and the one or more transmit ground conductors, in aggregate, cover more than 50% of a useable area of the substrate not occupied by the series resonators, the shunt resonators, and the signal conductors.
12. The duplexer device of claim 11, wherein
one end of each of the plurality of transmit surface acoustic wave shunt resonators is connected to one of the one or more transmit ground pads, and
one end of each of the plurality of receive surface acoustic wave shunt resonators is connected to one of the one or more receive ground pads.
13. The duplexer device of claim 11, wherein
the receive ground pads and receive ground conductor are electrically isolated from the transmit ground pads and the transmit ground conductors.
14. The filter device of claim 11, wherein the one or more receive ground conductors and the one or more transmit ground conductors, in aggregate, cover at least 70% of the useable area of the substrate not occupied by the series resonators, the shunt resonators, and the signal conductors.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for manufacturing a cubic silicon carbide single crystal thin film, the method comprising:
forming a sacrificial layer on a surface of a substrate;
forming a cubic semiconductor layer on a surface of the sacrificial layer, the cubic semiconductor layer having at least a surface of cubic crystal structure;
forming a cubic silicon carbide single crystal layer on the surface of the cubic semiconductor layer;
etching away the sacrificial layer to release a multilayer structure formed of the cubic semiconductor layer and the cubic silicon carbide single crystal layer from the substrate.
2. The method according to claim 1, wherein the substrate is a first substrate, the method further comprising bonding the multilayer structure to a second substrate with an exposed surface of the cubic semiconductor layer in contact with the second substrate.
3. The method according to claim 2, wherein the sacrificial layer is a ZnO single crystal layer;
the first substrate is a substrate selected from the group consisting of an SiC substrate, a sapphire substrate layer, an AlxGa1-xN (1\u2267\xd7\u22670) substrate, an InxGa1-xN (1\u2267\xd7\u22670) layer, and an AlxIn1-xN (1\u2267\xd7\u22670) layer; and
the cubic semiconductor layer is a nitride layer selected from the group consisting of an AlxGa1-xN (1\u2267\xd7\u22670) layer, an InxGa1-xN (1\u2267\xd7\u22670) layer, and an AlxIn1-xN (1\u2267\xd7\u22670) layer.
4. The method according to claim 2, wherein the sacrificial layer is an AlxGa1-xAs (1\u2267\xd7\u22670.6) layer, the first substrate is a GaAs substrate, and the cubic semiconductor layer is an AlxGa1-xAs (0.6 >\xd7\u22670) layer.
5. The method according to claim 1, wherein the sacrificial layer is a ZnO single crystal layer;
the substrate is a substrate selected from the group consisting of an SiC substrate, a sapphire substrate, an AlxGa1-xN (1\u2267\xd7\u22670) substrate, an InxGa1-xN (1\u2267\xd7\u22670) substrate, and an AlxIn1-xN (1\u2267\xd7\u22670) substrate; and
the cubic semiconductor layer is a nitride layer selected from the group consisting of an AlxGa1-xN (1\u2267\xd7\u22670) layer, an InxGa1-xN (1\u2267\xd7\u22670) layer, and an AlxIn1-xN (1\u2267\xd7\u22670) layer.
6. The method according to claim 1, wherein the sacrificial layer is an AlxGa1-xAs (1\u2267\xd7\u22670) layer, the substrate is a GaAs substrate, and the cubic semiconductor layer is an AlxGa1-xAs (1>\xd7\u22670) layer.
7. A semiconductor apparatus comprising:
a cubic silicon carbide single crystal thin film of a multilayer structure including an AlxGa1-xAs (0.6>\xd7\u22670) layer and a cubic silicon carbide single crystal layer; and
a substrate on which a metal layer is formed;
wherein the multilayer structure is bonded to a surface of the metal layer with the AlxGa1-xAs (0.6 >\xd7\u22670) in direct contact with the metal layer.
8. The semiconductor apparatus according to claim 7, wherein the contact resistance between the AlxGa1-xAs (0.6>\xd7\u22670) layer and the metal layer is lower than the resistance of the AlxGa1-xAs (0.6>\xd7\u22670) between two opposing principal surfaces of the AlxGa1-xAs (0.6>\xd7\u22670).