Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2000-01-12
2001-05-08
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S31300R
Reexamination Certificate
active
06229250
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a metallic thin-film applied to electrodes of various kinds of electronic parts and also relates to a method of manufacturing the metallic thin-film.
2. Description of the Related Art
As a result of the recent advances, the size of various types of electronic components such as capacitors, LSIs, coils, filters and oscillators have been reduced. This has made it necessary to provide thin-film electrodes for these components (such films are typically formed of aluminum or the like) which exhibit increased resistance to electric power. The crystallinity of such thin-films largely affects their resistance to electric power. When the thin-film material is polycrystalline or amorphous, atoms diffuse within grain boundaries under a high current density or a high stress which forms voids or hillocks in the thin-film. These voids or hillocks cause short circuits or disconnection. This phenomenon is referred to as electromigration or stressmigration.
To avoid this problem, it is necessary to create mono-crystalline structures which do not have the grain boundaries which serve as diffusion paths for the atoms. However, it is impossible to create such a mono-crystalline structure on a surface of an amorphous body, a polycrystalline body, or an orientation layer of a polycrystalline body by conventional film-forming methods.
SUMMARY OF THE INVENTION
The process of the present invention provides a metallic thin-film which is entirely or partially mono-crystalline in structure formed on the surface of a support body which has an amorphous or a polycrystalline structure, or which has a polycrystalline orientation layer, and a method for manufacturing such metallic thin-films.
In the preferred embodiment, the thin film electrode is arranged for use in a surface acoustic wave device which better withstands electric power than the prior art devices.
In accordance with the preferred embodiment, a metallic thin-film of the present invention has an entirely or partially mono-crystalline structure, and is formed on the surface of an amorphous body, a polycrystalline body, or an orientation layer of a polycrystalline body, under the influence of a radiated beam which assists the film formation onto the surface of the amorphous body, the polycrystalline body, or the orientation layer.
Preferably, at least one type of ion selected from the group consisting of argon, helium, neon, krypton, and xenon ions, or a mixture thereof is used for the irradiating ion beam. The metallic thin-film is preferably composed of aluminum, gold, silver, copper, platinum, titanium, chromium, nickel, tungsten, an alloy thereof, or an alloy essentially consisting of at least one of the above elements.
According to one aspect of the present invention, there is provided a thin film electrode for use in a surface acoustic wave device and a surface acoustic wave device comprising an amorphous layer formed on a piezoelectric substrate, and at least one of a single crystal layer and an oriented layer formed on the amorphous layer.
According to another aspect of the present invention, there is provided a method of forming a surface acoustic wave device having a thin film electrode formed thereon, the method comprising the steps of forming an amorphous layer on a surface of a piezoelectric substrate while irradiating the surface of the piezoelectric substrate with an ion beam, and thereafter forming at least one of a single crystal layer and an oriented layer on a surface of the amorphous layer with the assist ion beam.
REFERENCES:
patent: 3736045 (1973-05-01), Heidrich et al.
patent: 4655850 (1987-04-01), Kakimoto et al.
patent: 4684841 (1987-08-01), Este et al.
patent: 5440188 (1995-08-01), Krempl et al.
patent: 5446330 (1995-08-01), Eda et al.
patent: 5920143 (1999-07-01), Tarui et al.
patent: 0 200 304 (1986-12-01), None
Kobayashi Masato
Nakanishi Hidefumi
Sakurai Atsushi
Yoshino Yukio
Dougherty Thomas M.
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
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