Electronic device and electronic apparatus

Abstract

Performance of an electronic device is highly improved by epitaxially growing a perovskite-type oxide thin film on an inorganic amorphous layer or an organic solid layer in a desired direction; and furthermore, a high performance electronic device is provided by incorporating the electronic device into an integrated circuit, wherein oxide thin layers are formed on the inorganic amorphous layer or the organic solid layer, and the perovskite-type oxide thin film is grown epitaxially on the oxide layer, the oxide thin layers being able to be at least one of strontium oxide, magnesium oxide, cerium oxide, zirconium oxide, yttrium stabilized zirconium oxide, and strontium titanate; and as the perovskite-type oxide thin film, the perovskite-type oxide thin film being a piezoelectric or ferroelectric material, for example, is used.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional patent application of U.S. Ser. No. 10 / 108,180 filed Mar. 27, 2002, claiming priority to JPSN 2001-093924 filed Mar. 28, 2001, JPSN 2002-076695 filed Mar. 19, 2002 and JPSN 2002-085812 filed Mar. 26, 2002, all of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an electronic device, especially, a ferroelectric device, a surface acoustic device, and a piezoelectric device, based on a perovskite-type oxide thin film grown epitaxially on an oxide thin layer on an inorganic amorphous layer or an organic solid layer, and an electronic apparatus comprising the electronic device. [0004] 2. Description of the Related Art [0005] Conventionally, when a perovskite-type oxide thin film is grown epitaxially, a single crystal substrate or a crystallized buffer layer is chosen by considering lattice matching with a perovskite...

AI Technical Summary

Benefits of technology

[0017] Silicon oxide (described as SiO2 hereafter), aluminum nitride (described as AlN hereafter), glass, amorphous silicon or the like can be used for the inorganic amorphous layer. Among these, the use of SiO2 is preferable because, in many cases, an electronic device of the present invention is formed on a silicon substrate, on which SiO2 is easily formed, or it is often already formed thereon.

[0019] It is preferable that the oxide thin layer comprise at least one of strontium oxide (described as “SrO” hereafter), magnesium oxide (described as “MgO” hereafter), cerium oxide (described as “CeO2” hereafter), zirconium oxide (described as “ZrO2” hereafter), yttrium stabilized zirconium oxide (described as “YSZ” hereafter), barium oxide (described as “BaO” hereafter), and calcium oxide (described as “CaO” hereafter). These oxide materials permit a high quality perovskite-type oxide thin film to be formed thereon.

[0024] According to the present invention, by including a suitable inorganic amorphous layer or an organic solid layer, as well as an oxide thin layer formed on the inorganic amorphous layer or the organic solid layer, and furthermore, by including a perovskite-type oxide thin film grown epitaxially on the oxide thin layer, and by using a suitable substrate including an inorganic amorphous layer or an organic layer, it is possible to provide an electronic device having a perovskite-type oxide thin film grown epitaxially in a desired direction on the inorganic amorphous layer or the organic solid layer. Furthermore, a high performance electronic device such as a surface acoustic device, a ferroelectric memory device, or a piezoelectric device can be provided by further incorporating such a device into an integrated circuit. Further, according to the present invention, a high performance electronic apparatus comprising any of the above electronic devices is provided.

Problems solved by technology

In an oriented film, packing density is lower than that in an epitaxial film, in-plane orientation is not as uniform, and crystallization is not as fully controlled.

Even though oxide ceramics such as SrTiO3 are normally used as a single crystal substrate, the cost of oxide ceramic substrates is generally high, and fabrication of large substrates of 3 inches or more in diameter is difficult depending on the types.

Even though a technology to grow a perovskite-type oxide thin film epitaxially on a silicon substrate is highly valuable in terms of cost and other factors, the technology alone cannot accomplish the desired integration with semiconductor devices.

Also, when a piezoelectric device such as an actuator is fabricated, a perovskite-type oxide thin film must be formed on a thermally oxidized film of a silicon oxide as well, so that a technology to form a perovskite-type oxide thin film on a silicon substrate alone is not sufficient.

There are examples of forming perovskite-type oxide thin films on a crystallized film of platinum or the like formed on an amorphous silicon oxide film; however, even though oriented films can be obtained in such cases, epitaxial films cannot be obtained.

As described in Japanese Unexamined Patent Application, First Publication No. 9-100125, there is an example of forming KNbO3 on an amorphous substrate; however, what is obtained is an oriented film, and obtaining an epitaxial film is still difficult.

It is difficult, furthermore, to grow a crystal in a desired orientation direction.

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