Composite substrate and acoustic wave device
A composite substrate includes a support substrate made of Si, a high acoustic velocity material layer, a low acoustic velocity film, and a piezoelectric layer. In Euler angles (φ, θ, ψ) of the Si, φ and θ are within regions indicated by hatching with slant lines in FIG. 4 . An acoustic wave device includes an IDT electrode in contact with the piezoelectric layer of the composite substrate.
1 . A composite substrate, comprising:
a support substrate made of Si; and
a piezoelectric layer laminated on the support substrate; wherein
Euler angles of the Si are within any of ranges in Tables 1 to 3 below:
TABLE 1
φ
θ
−90° ≤ φ < −89°
−13° ≥ θ ≥ −16°, −73° ≥ θ ≥ −75°
−89° ≤ φ < −88°
−14° ≥ θ ≥ −15°, −72° ≥ θ ≥ −75°
−88° ≤ φ < −87°
−71° ≥ θ ≥ −75°
−87° ≤ φ < −86°
−70° ≥ θ ≥ −75°
−86° ≤ φ < −85°
−69° ≥ θ ≥ −80°
−85° ≤ φ < −84°
−69° ≥ θ ≥ −80°
−84° ≤ φ < −83°
−69° ≥ θ ≥ −79°
−83° ≤ φ < −82°
−19° ≥ θ ≥ −22°, −69° ≥ θ ≥ −74°, −76° ≥ θ ≥ −77°
−82° ≤ φ < −81°
−19° ≥ θ ≥ −22°, −68° ≥ θ ≥ −74°
−81° ≤ φ < −80°
−18° ≥ θ ≥ −22°, −68° ≥ θ ≥ −73°
−80° ≤ φ < −79°
−18° ≥ θ ≥ −22°, −67° ≥ θ ≥ −73°
−79° ≤ φ < −78°
−18° ≥ θ ≥ −22°, −67° ≥ θ ≥ −74°
−78° ≤ φ < −77°
−18° ≥ θ ≥ −22°, −66° ≥ θ ≥ −75°
−77° ≤ φ < −76°
−18° ≥ θ ≥ −22°, −65° ≥ θ ≥ −75°, −87° ≥ θ ≥ −88°
−76° ≤ φ < −75°
−18° ≥ θ ≥ −22°, −64° ≥ θ ≥ −75°, −84° ≥ θ ≥ −90°
−75° ≤ φ < −74°
−17° ≥ θ ≥ −21°, −63° ≥ θ ≥ −77°, −83° ≥ θ ≥ −90°
−74° ≤ φ < −73°
−17° ≥ θ ≥ −21°, −62° ≥ θ ≥ −78°, −81° ≥ θ ≥ −86°
−73° ≤ φ < −72°
−16° ≥ θ ≥ −21°, −61° ≥ θ ≥ −79°, −80° ≥ θ ≥ −87°
−72° ≤ φ < −71°
−15° ≥ θ ≥ −21°, −54° ≥ θ ≥ −59°, −60° ≥ θ ≥ −87°
−71° ≤ φ < −70°
−14° ≥ θ ≥ −30°, −52° ≥ θ ≥ −88°
−70° ≤ φ < −69°
−13° ≥ θ ≥ −30°, −39° ≥ θ ≥ −40°, −50° ≥ θ ≥ −88°
−69° ≤ φ < −68°
−13° ≥ θ ≥ −29°, −37° ≥ θ ≥ −40°, −50° ≥ θ ≥ −88°
−68° ≤ φ < −67°
−13° ≥ θ ≥ −29°, −36° ≥ θ ≥ −40°, −49° ≥ θ ≥ −77°,
−79° ≥ θ ≥ −88°
−67° ≤ φ < −66°
−13° ≥ θ ≥ −28°, −35° ≥ θ ≥ −40°, −49° ≥ θ ≥ −75°,
−81° ≥ θ ≥ −88°
−66° ≤ φ < −65°
−13° ≥ θ ≥ −28°, −33° ≥ θ ≥ −40°, −49° ≥ θ ≥ −73°,
−83° ≥ θ ≥ −87°
−65° ≤ φ < −64°
−13° ≥ θ ≥ −28°, −32° ≥ θ ≥ −40°, −48° ≥ θ ≥ −64°,
−65° ≥ θ ≥ −72°
−64° ≤ φ < −63°
−17° ≥ θ ≥ −28°, −31° ≥ θ ≥ −40°, −46° ≥ θ ≥ −61°,
−66° ≥ θ ≥ −73°
−63° ≤ φ < −62°
−17° ≥ θ ≥ −40°, −44° ≥ θ ≥ −49°, −50° ≥ θ ≥ −59°,
−66° ≥ θ ≥ −73°
−62° ≤ φ < −61°
−18° ≥ θ ≥ −40°, −42° ≥ θ ≥ −49°, −51° ≥ θ ≥ −57°,
−67° ≥ θ ≥ −72°
−61° ≤ φ < −60°
−18° ≥ θ ≥ −49°, −52° ≥ θ ≥ −56°, −67° ≥ θ ≥ −72°
TABLE 2
φ
θ
−60° ≤ φ < −59°
−18° ≥ θ ≥ −48°, −52° ≥ θ ≥ −54°, −67° ≥ θ ≥ −73°
−59° ≤ φ < −58°
−18° ≥ θ ≥ −48°, −68° ≥ θ ≥ −73°
−58° ≤ φ < −57°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−57° ≤ φ < −56°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−56° ≤ φ < −55°
−20° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−55° ≤ φ < −54°
−20° ≥ θ ≥ −47°, −67° ≥ θ ≥ −73°
−54° ≤ φ < −53°
−20° ≥ θ ≥ −44°, −67° ≥ θ ≥ −73°
−53° ≤ φ < −52°
−20° ≥ θ ≥ −43°, −67° ≥ θ ≥ −73°
−52° ≤ φ < −51°
−19° ≥ θ ≥ −42°, −67° ≥ θ ≥ −72°
−51° ≤ φ < −50°
−19° ≥ θ ≥ −24°, −27° ≥ θ ≥ −41°, −68° ≥ θ ≥ −72°
−50° ≤ φ < −49°
−25° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−49° ≤ φ < −48°
−24° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−48° ≤ φ < −47°
−24° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−47° ≤ φ < −46°
−23° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−46° ≤ φ < −45°
−23° ≥ θ ≥ −39°, −68° ≥ θ ≥ −72°
−44° ≤ φ < −43°
−21° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−43° ≤ φ < −42°
−19° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−42° ≤ φ < −41°
−18° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−41° ≤ φ < −40°
−17° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−40° ≤ φ < −39°
−17° ≥ θ ≥ −23°, −24° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−39° ≤ φ < −38°
−17° ≥ θ ≥ −22°, −23° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−38° ≤ φ < −37°
−17° ≥ θ ≥ −21°, −22° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−37° ≤ φ < −36°
−19° ≥ θ ≥ −20°, −21° ≥ θ ≥ −45°, −67° ≥ θ ≥ −72°
−36° ≤ φ < −35°
−21° ≥ θ ≥ −47°, −68° ≥ θ ≥ −72°
−35° ≤ φ < −34°
−20° ≥ θ ≥ −48°, −67° ≥ θ ≥ −72°
−34° ≤ φ < −33°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −72°
−33° ≤ φ < −32°
−19° ≥ θ ≥ −30°, −34° ≥ θ ≥ −48°, −66° ≥ θ ≥ −72°
−32° ≤ φ < −31°
−18° ≥ θ ≥ −29°, −35° ≥ θ ≥ −48°, −65° ≥ θ ≥ −73°
−31° ≤ φ < −30°
−18° ≥ θ ≥ −29°, −37° ≥ θ ≥ −48°, −52° ≥ θ ≥ −56°,
−64° ≥ θ ≥ −73°
TABLE 3
φ
θ
−30° ≤ φ < −29°
−17° ≥ θ ≥ −29°, −39° ≥ θ ≥ −48°, −51° ≥ θ ≥ −56°,
−63° ≥ θ ≥ −73°
−29° ≤ φ < −28°
−16° ≥ θ ≥ −28°, −40° ≥ θ ≥ −47°, −51° ≥ θ ≥ −57°,
−61° ≥ θ ≥ −73°
−28° ≤ φ < −27°
−15° ≥ θ ≥ −28°, −41° ≥ θ ≥ −46°, −50° ≥ θ ≥ −73°
−27° ≤ φ < −26°
−14° ≥ θ ≥ −28°, −50° ≥ θ ≥ −73°
−26° ≤ φ < −25°
−13° ≥ θ ≥ −28°, −49° ≥ θ ≥ −73°, −84° ≥ θ ≥ −85°
−25° ≤ φ < −24°
−14° ≥ θ ≥ −27°, −49° ≥ θ ≥ −75°, −82° ≥ θ ≥ −85°
−24° ≤ φ < −23°
−14° ≥ θ ≥ −27°, −49° ≥ θ ≥ −62°, −63° ≥ θ ≥ −79°,
−81° ≥ θ ≥ −86°
−23° ≤ φ < −22°
−14° ≥ θ ≥ −26°, −50° ≥ θ ≥ −61°, −63° ≥ θ ≥ −87°
−22° ≤ φ < −21°
−14° ≥ θ ≥ −29°, −50° ≥ θ ≥ −60°, −63° ≥ θ ≥ −87°
−21° ≤ φ < −20°
−14° ≥ θ ≥ −30°, −51° ≥ θ ≥ −58°, −63° ≥ θ ≥ −88°
−20° ≤ φ < −19°
−14° ≥ θ ≥ −25°, −52° ≥ θ ≥ −56°, −64° ≥ θ ≥ −88°
−19° ≤ φ < −18°
−14° ≥ θ ≥ −24°, −64° ≥ θ ≥ −79°, −80° ≥ θ ≥ −88°
−18° ≤ φ < −17°
−14° ≥ θ ≥ −23°, −64° ≥ θ ≥ −78°, −82° ≥ θ ≥ −89°
−17° ≤ φ < −16°
−14° ≥ θ ≥ −22°, −64° ≥ θ ≥ −77°, −85° ≥ θ ≥ −90°
−16° ≤ φ < −15°
−14° ≥ θ ≥ −22°, −64° ≥ θ ≥ −76°, −87° ≥ θ ≥ −90°
−15° ≤ φ < −14°
−16° ≥ θ ≥ −22°, −64° ≥ θ ≥ −75°, −89° ≥ θ ≥ −90°
−14° ≤ φ < −13°
−17° ≥ θ ≥ −22°, −67° ≥ θ ≥ −75°
−13° ≤ φ < −12°
−18° ≥ θ ≥ −22°, −68° ≥ θ ≥ −75°
−12° ≤ φ < −11°
−18° ≥ θ ≥ −25°, −68° ≥ θ ≥ −75°
−11° ≤ φ < −10°
−18° ≥ θ ≥ −25°, −68° ≥ θ ≥ −74°
−10° ≤ φ < −9°
−18° ≥ θ ≥ −25°, −67° ≥ θ ≥ −73°
−9° ≤ φ < −8°
−17° ≥ θ ≥ −25°, −67° ≥ θ ≥ −72°
−8° ≤ φ < −7°
−18° ≥ θ ≥ −20°, −66° ≥ θ ≥ −71°, −74° ≥ θ ≥ −75°
−7° ≤ φ < −6°
−68° ≥ θ ≥ −70°, −73° ≥ θ ≥ −75°
−6° ≤ φ < −5°
−72° ≥ θ ≥ −80°
−5° ≤ φ < −4°
−73° ≥ θ ≥ −80°
−4° ≤ φ < −3°
−74° ≥ θ ≥ −79°
−3° ≤ φ < −2°
−73° ≥ θ ≥ −78°
−2° ≤ φ < −1°
−14° ≥ θ ≥ −16°, −73° ≥ θ ≥ −77°
−1° ≤ φ < 0°
−14° ≥ θ ≥ −16°, −73° ≥ θ ≥ −76°.
2 . The composite substrate according to claim 1 , wherein
an acoustic velocity of a longitudinal wave propagating through the Si is less than or equal to about 9150 m/sec; and
in the Euler angles (φ, θ, ψ) of the Si, φ is other than about 0° or θ is other than about 0°.
3 . The composite substrate according to claim 2 , wherein the acoustic velocity of the longitudinal wave propagating through the Si is less than or equal to about 9080 m/sec.
4 . An acoustic wave device, comprising:
the composite substrate according to claim 1 ; and
an IDT electrode in contact with the piezoelectric layer of the composite substrate.
5 . The acoustic wave device according to claim 4 , wherein the IDT electrode is on a surface of the piezoelectric layer on an opposite side to the support substrate.
6 . The acoustic wave device according to claim 4 , wherein in the Euler angles (φ, θ, ψ) of the Si, φ is in a range from about −25° to about −15°, and θ is in a range from about −22° to about −14°.
7 . The acoustic wave device according to claim 4 , wherein
an acoustic velocity of the longitudinal wave propagating through the Si is less than or equal to about 9150 m/sec; and
in the Euler angles (φ, θ, ψ) of the Si, φ is other than about 0° or θ is other than about 0°.
8 . The acoustic wave device according to claim 7 , wherein the acoustic velocity of the longitudinal wave propagating through the Si is less than or equal to about 9080 m/sec.
9 . A composite substrate, comprising:
a support substrate made of Si;
a piezoelectric layer made of lithium tantalate laminated on the support substrate;
a high acoustic velocity film between the support substrate and the piezoelectric layer, in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity film is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer; and
a low acoustic velocity film between the high acoustic velocity film and the piezoelectric layer, in which an acoustic velocity of a bulk wave propagating through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer; wherein
Euler angles of the Si are within any of ranges in Tables 4 to 6 below:
TABLE 4
φ
θ
−90° ≤ φ < −89°
−13° ≥ θ ≥ −16°, −73° ≥ θ ≥ −75°
−89° ≤ φ < −88°
−14° ≥ θ ≥ −15°, −72° ≥ θ ≥ −75°
−88° ≤ φ < −87°
−71° ≥ θ ≥ −75°
−87° ≤ φ < −86°
−70° ≥ θ ≥ −75°
−86° ≤ φ < −85°
−69° ≥ θ ≥ −80°
−85° ≤ φ < −84°
−69° ≥ θ ≥ −80°
−84° ≤ φ < −83°
−69° ≥ θ ≥ −79°
−83° ≤ φ < −82°
−19° ≥ θ ≥ −22°, −69° ≥ θ ≥ −74°, −76° ≥ θ ≥ −77°
−82° ≤ φ < −81°
−19° ≥ θ ≥ −22°, −68° ≥ θ ≥ −74°
−81° ≤ φ < −80°
−18° ≥ θ ≥ −22°, −68° ≥ θ ≥ −73°
−80° ≤ φ < −79°
−18° ≥ θ ≥ −22°, −67° ≥ θ ≥ −73°
−79° ≤ φ < −78°
−18° ≥ θ ≥ −22°, −67° ≥ θ ≥ −74°
−78° ≤ φ < −77°
−18° ≥ θ ≥ −22°, −66° ≥ θ ≥ −75°
−77° ≤ φ < −76°
−18° ≥ θ ≥ −22°, −65° ≥ θ ≥ −75°, −87° ≥ θ ≥ −88°
−76° ≤ φ < −75°
−18° ≥ θ ≥ −22°, −64° ≥ θ ≥ −75°, −84° ≥ θ ≥ −90°
−75° ≤ φ < −74°
−17° ≥ θ ≥ −21°, −63° ≥ θ ≥ −77°, −83° ≥ θ ≥ −90°
−74° ≤ φ < −73°
−17° ≥ θ ≥ −21°, −62° ≥ θ ≥ −78°, −81° ≥ θ ≥ −86°
−73° ≤ φ < −72°
−16° ≥ θ ≥ −21°, −61° ≥ θ ≥ −79°, −80° ≥ θ ≥ −87°
−72° ≤ φ < −71°
−15° ≥ θ ≥ −21°, −54° ≥ θ ≥ −59°, −60° ≥ θ ≥ −87°
−71° ≤ φ < −70°
−14° ≥ θ ≥ −30°, −52° ≥ θ ≥ −88°
−70° ≤ φ < −69°
−13° ≥ θ ≥ −30°, −39° ≥ θ ≥ −40°, −50° ≥ θ ≥ −88°
−69° ≤ φ < −68°
−13° ≥ θ ≥ −29°, −37° ≥ θ ≥ −40°, −50° ≥ θ ≥ −88°
−68° ≤ φ < −67°
−13° ≥ θ ≥ −29°, −36° ≥ θ ≥ −40°, −49° ≥ θ ≥ −77°,
−79° ≥ θ ≥ −88°
−67° ≤ φ < −66°
−13° ≥ θ ≥ −28°, −35° ≥ θ ≥ −40°, −49° ≥ θ ≥ −75°,
−81° ≥ θ ≥ −88°
−66° ≤ φ < −65°
−13° ≥ θ ≥ −28°, −33° ≥ θ ≥ −40°, −49° ≥ θ ≥ −73°,
−83° ≥ θ ≥ −87°
−65° ≤ φ < −64°
−13° ≥ θ ≥ −28°, −32° ≥ θ ≥ −40°, −48° ≥ θ ≥ −64°,
−65° ≥ θ ≥ −72°
−64° ≤ φ < −63°
−17° ≥ θ ≥ −28°, −31° ≥ θ ≥ −40°, −46° ≥ θ ≥ −61°,
−66° ≥ θ ≥ −73°
−63° ≤ φ < −62°
−17° ≥ θ ≥ −40°, −44° ≥ θ ≥ −49°, −50° ≥ θ ≥ −59°,
−66° ≥ θ ≥ −73°
−62° ≤ φ < −61°
−18° ≥ θ ≥ −40°, −42° ≥ θ ≥ −49°, −51° ≥ θ ≥ −57°,
−67° ≥ θ ≥ −72°
−61° ≤ φ < −60°
−18° ≥ θ ≥ −49°, −52° ≥ θ ≥ −56°, −67° ≥ θ ≥ −72°
TABLE 5
φ
θ
−60° ≤ φ < −59°
−18° ≥ θ ≥ −48°, −52° ≥ θ ≥ −54°, −67° ≥ θ ≥ −73°
−59° ≤ φ < −58°
−18° ≥ θ ≥ −48°, −68° ≥ θ ≥ −73°
−58° ≤ φ < −57°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−57° ≤ φ < −56°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−56° ≤ φ < −55°
−20° ≥ θ ≥ −48°, −67° ≥ θ ≥ −73°
−55° ≤ φ < −54°
−20° ≥ θ ≥ −47°, −67° ≥ θ ≥ −73°
−54° ≤ φ < −53°
−20° ≥ θ ≥ −44°, −67° ≥ θ ≥ −73°
−53° ≤ φ < −52°
−20° ≥ θ ≥ −43°, −67° ≥ θ ≥ −73°
−52° ≤ φ < −51°
−19° ≥ θ ≥ −42°, −67° ≥ θ ≥ −72°
−51° ≤ φ < −50°
−19° ≥ θ ≥ −24°, −27° ≥ θ ≥ −41°, −68° ≥ θ ≥ −72°
−50° ≤ φ < −49°
−25° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−49° ≤ φ < −48°
−24° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−48° ≤ φ < −47°
−24° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−47° ≤ φ < −46°
−23° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−46° ≤ φ < −45°
−23° ≥ θ ≥ −39°, −68° ≥ θ ≥ −72°
−45° ≤ φ < −44°
−22° ≥ θ ≥ −39°, −68° ≥ θ ≥ −72°
−44° ≤ φ < −43°
−21° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−43° ≤ φ < −42°
−19° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−42° ≤ φ < −41°
−18° ≥ θ ≥ −40°, −68° ≥ θ ≥ −72°
−41° ≤ φ < −40°
−17° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−40° ≤ φ < −39°
−17° ≥ θ ≥ −23°, −24° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−39° ≤ φ < −38°
−17° ≥ θ ≥ −22°, −23° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−38° ≤ φ < −37°
−17° ≥ θ ≥ −21°, −22° ≥ θ ≥ −41°, −67° ≥ θ ≥ −72°
−37° ≤ φ < −36°
−19° ≥ θ ≥ −20°, −21° ≥ θ ≥ −45°, −67° ≥ θ ≥ −72°
−36° ≤ φ < −35°
−21° ≥ θ ≥ −47°, −68° ≥ θ ≥ −72°
−35° ≤ φ < −34°
−20° ≥ θ ≥ −48°, −67° ≥ θ ≥ −72°
−34° ≤ φ < −33°
−19° ≥ θ ≥ −48°, −67° ≥ θ ≥ −72°
−33° ≤ φ < −32°
−19° ≥ θ ≥ −30°, −34° ≥ θ ≥ −48°, −66° ≥ θ ≥ −72°
−32° ≤ φ < −31°
−18° ≥ θ ≥ −29°, −35° ≥ θ ≥ −48°, −65° ≥ θ ≥ −73°
−31° ≤ φ < −30°
−18° ≥ θ ≥ −29°, −37° ≥ θ ≥ −48°,
−52° ≥ θ ≥ −56°, −64° ≥ θ ≥ −73°
TABLE 6
φ
θ
−30° ≤ φ < −29°
−17° ≥ θ ≥ −29°, −39° ≥ θ ≥ −48°, −51° ≥ θ ≥ −56°,
−63° ≥ θ ≥ −73°
−29° ≤ φ < −28°
−16° ≥ θ ≥ −28°, −40° ≥ θ ≥ −47°, −51° ≥ θ ≥ −57°,
−61° ≥ θ ≥ −73°
−28° ≤ φ < −27°
−15° ≥ θ ≥ −28°, −41° ≥ θ ≥ −46°, −50° ≥ θ ≥ −73°
−27° ≤ φ < −26°
−14° ≥ θ ≥ −28°, −50° ≥ θ ≥ −73°
−26° ≤ φ < −25°
−13° ≥ θ ≥ −28°, −49° ≥ θ ≥ −73°, −84° ≥ θ ≥ −85°
−25° ≤ φ < −24°
−14° ≥ θ ≥ −27°, −49° ≥ θ ≥ −75°, −82° ≥ θ ≥ −85°
−24° ≤ φ < −23°
−14° ≥ θ ≥ −27°, −49° ≥ θ ≥ −62°, −63° ≥ θ ≥ −79°,
−81° ≥ θ ≥ −86°
−23° ≤ φ < −22°
−14° ≥ θ ≥ −26°, −50° ≥ θ ≥ −61°, −63° ≥ θ ≥ −87°
−22° ≤ φ < −21°
−14° ≥ θ ≥ −29°, −50° ≥ θ ≥ −60°, −63° ≥ θ ≥ −87°
−21° ≤ φ < −20°
−14° ≥ θ ≥ −30°, −51° ≥ θ ≥ −58°, −63° ≥ θ ≥ −88°
−20° ≤ φ < −19°
−14° ≥ θ ≥ −25°, −52° ≥ θ ≥ −56°, −64° ≥ θ ≥ −88°
−19° ≤ φ < −18°
−14° ≥ θ ≥ −24°, −64° ≥ θ ≥ −79°, −80° ≥ θ ≥ −88°
−18° ≤ φ < −17°
−14° ≥ θ ≥ −23°, −64° ≥ θ ≥ −78°, −82° ≥ θ ≥ −89°
−17° ≤ φ < −16°
−14° ≥ θ ≥ −22°, −64° ≥ θ ≥ −77°, −85° ≥ θ ≥ −90°
−16° ≤ φ < −15°
−14° ≥ θ ≥ −22°, −64° ≥ θ ≥ −76°, −87° ≥ θ ≥ −90°
−15° ≤ φ < −14°
−16° ≥ θ ≥ −22°, −64° ≥ θ ≥ −75°, −89° ≥ θ ≥ −90°
−14° ≤ φ < −13°
−17° ≥ θ ≥ −22°, −67° ≥ θ ≥ −75°
−13° ≤ φ < −12°
−18° ≥ θ ≥ −22°, −68° ≥ θ ≥ −75°
−12° ≤ φ < −11°
−18° ≥ θ ≥ −25°, −68° ≥ θ ≥ −75°
−11° ≤ φ < −10°
−18° ≥ θ ≥ −25°, −68° ≥ θ ≥ −74°
−10° ≤ φ < −9°
−18° ≥ θ ≥ −25°, −67° ≥ θ ≥ −73°
−9° ≤ φ < −8°
−17° ≥ θ ≥ −25°, −67° ≥ θ ≥ −72°
−8° ≤ φ < −7°
−18° ≥ θ ≥ −20°, −66° ≥ θ ≥ −71°, −74° ≥ θ ≥ −75°
−7° ≤ φ < −6°
−68° ≥ θ ≥ −70°, −73° ≥ θ ≥ −75°
−6° ≤ φ < −5°
−72° ≥ θ ≥ −80°
−5° ≤ φ < −4°
−73° ≥ θ ≥ −80°
−4° ≤ φ < −3°
−74° ≥ θ ≥ −79°
−3° ≤ φ < −2°
−73° ≥ θ ≥ −78°
−2° ≤ φ < −1°
−14° ≥ θ ≥ −16°, −73° ≥ θ ≥ −77°
−1° ≤ φ < 0°
−14° ≥ θ ≥ −16°, −73° ≥ θ ≥ −76°.
10 . The composite substrate according to claim 9 , wherein
an acoustic velocity of a longitudinal wave propagating through the Si is less than or equal to about 9150 m/sec; and
in the Euler angles (φ, θ, ψ) of the Si, φ is other than about 0° or θ is other than about 0°.
11 . The composite substrate according to claim 10 , wherein the acoustic velocity of the longitudinal wave propagating through the Si is less than or equal to about 9080 m/sec.
12 . An acoustic wave device, comprising:
the composite substrate according to claim 1 ; and
an IDT electrode in contact with the piezoelectric layer of the composite substrate.
13 . The acoustic wave device according to claim 12 , wherein the IDT electrode is on a surface of the piezoelectric layer on an opposite side to the support substrate.
14 . The acoustic wave device according to claim 12 , wherein in the Euler angles (φ, θ, ψ) of the Si, φ is in a range from about −25° to about −15°, and θ is in a range from about −22° to about −14°.
15 . The acoustic wave device according to claim 12 , wherein
an acoustic velocity of a longitudinal wave propagating through the Si is less than or equal to about 9150 m/sec; and
in the Euler angles (φ, θ, ψ) of the Si, φ is other than about 0° or θ is other than about 0°.
16 . The acoustic wave device according to claim 15 , wherein the acoustic velocity of the longitudinal wave propagating through the Si is less than or equal to about 9080 m/sec.
17 . A composite substrate, comprising:
a support substrate made of Si;
a piezoelectric layer made of lithium tantalate laminated on the support substrate;
a high acoustic velocity film between the support substrate and the piezoelectric layer, in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity film is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer; and
a low acoustic velocity film between the high acoustic velocity film and the piezoelectric layer, in which an acoustic velocity of a bulk wave propagating through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer; wherein
in Euler angles (φ, θ, ψ) of the Si, φ is in a range from about −25° to about −15°, and θ is in a range from about −22° to about −14°.
18 . A composite substrate, comprising:
a support substrate made of Si; and
a piezoelectric layer laminated on the support substrate; wherein
in the Euler angles (φ, θ, ψ) of the Si, φ is in a range from about −25° to about −15°, and θ is in a range from about −22° to about −14°.