JPS6283462A - Method for producing oriented metal thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 2.X The present invention relates to a method for manufacturing an oriented metal thin film that is applied as an electrode for various thin film devices.

BACKGROUND OF THE INVENTION Epitaxial films and alignment films are attracting attention due to their material properties in thin film elements applied to optoelectronic devices such as pyroelectric infrared sensors, piezoelectric devices, and optical modulators.

When using the above thin film as a device, it is necessary to form a metal thin film as an electrode between the thin film and the substrate, especially in order to utilize the physical properties of the thin film in the thickness direction.

For example, a thin film element C11 that utilizes pyroelectricity generated in the direction of the orientation axis by providing electrodes perpendicular to the orientation axis of a (001) oriented lead titanate film has a dielectric constant that is higher than that of a non-oriented one. The figure of merit of the pyroelectric material (pyroelectric coefficient/permittivity) increases. As a result, a highly sensitive infrared detector is provided.

However, since the metal film produced as a stain electrode by vacuum evaporation or sputtering is amorphous or polycrystalline, the thin film grown on the soil is not oriented and becomes polycrystalline. Its electrical characteristics will also deteriorate. To solve this problem, Japanese Patent Application No. 58-16506 proposes a method of manufacturing an oriented metal thin film by sputtering in an argon gas atmosphere containing oxygen.

Problems to be Solved by the Invention In a thin film device in which a metal R film is formed as an electrode between the thin film and a substrate in order to utilize properties in the thickness direction of an epitaxial or oriented thin film, the crystals of the thin film are The property and orientation strongly depend on the metal thin film. It is difficult to fabricate an epitaxial, oriented thin film on a polycrystalline metal thin film, and the properties of the thin film are significantly degraded.

Means to Solve the Problems In the process of producing a metal thin film by sputtering, the first step is to form the metal thin film in an argon gas atmosphere containing oxygen, and the second step is to form the desired film thickness in an argon gas atmosphere only. It is characterized by consisting of a second process.

A thin metal film is formed on the surface of the metal in an argon gas atmosphere containing 6 or more oxygen in the working volume percentage, and then formed to the desired film thickness in an argon gas atmosphere. Compared to the method of forming in an argon gas atmosphere containing oxygen from beginning to end,
A metal thin film with increased X-ray diffraction intensity in the 0) direction and lower electrical resistance was obtained.

This is attributed to the gradual decrease in the influence of oxygen ions, oxygen molecules, and molecules. 4. Thin film formation speed has also improved.

A metal thin film was produced on the pleated magnesium oxide substrate in Example (100) by high frequency magnetron sputtering.

The temperature of the substrate was set to eoo'c. As the initial atmospheric gas, argon gas mixed with oxygen was used.

The total pressure was 0.5 Pa, and the thin film formation at this time6'\-・ The speed was 30-40 people/min (first process).

After a predetermined period of time, the mixing of oxygen was stopped, and sputtering was performed in an atmosphere of only argon gas to obtain an oriented metal thin film with a desired thickness (second step).
The crystals were identified and their orientation determined by line diffraction and electron diffraction.

Figures 1a and 1b show the X-ray diffraction patterns of gold and platinum.

In the case of platinum, FIG. 2 shows how the X-ray diffraction intensity changes when the time tl of the first process of forming a thin film in an oxygen-containing argon gas atmosphere is changed. tl
is between 2 and 5 minutes, and when the thickness of the metal thin film formed in the first step is between 6 OA and 150 Å, the X-ray diffraction intensity shows a peak, and the X-ray diffraction intensity shows a peak in the argon gas atmosphere containing oxygen from beginning to end. It is clear that the diffraction intensity has increased compared to the case where it is formed (marked in the figure). Further, the thin film formation rate in the second process of sputtering in an atmosphere of argon gas only was approximately 70 persons/min, which was approximately twice the formation rate in the first process. Therefore, the total sputtering time was also reduced by almost half. It should be noted that all the film thicknesses of the platinum 61/-7 thin film are based on data of approximately 1,000 mm.

FIG. 3 shows changes in the diffraction intensity of platinum when the oxygen mixing ratio was changed in the first step. As is clear from the figure, the diffraction intensity increases at a mixing ratio of 6 or more.

In the electron beam diffraction images of (100) oriented gold and platinum thin films, each diffraction point was separated and appeared in the form of spots, confirming epitaxial growth on magnesium oxide.

1. When formed in an argon gas atmosphere containing oxygen throughout, the electrical resistance sometimes showed large values, but the one made according to the present invention stably shows a value close to that of pulp, and even an extremely thin film can function as an electrode. This was confirmed.

As described above, according to the manufacturing method of the present invention, a metal thin film with <100> orientation, crystallinity, and low electrical resistance can be produced stably and with good reproducibility. The thin film formation speed has also improved.

[Brief explanation of drawings]

Figures 1a and b are characteristic diagrams showing the X-ray diffraction patterns of gold and platinum thin films produced by the manufacturing method of the present invention, respectively, and Figure 2 is a platinum thin film diffraction pattern when the time of the first process: tl is changed. FIG. 3 is a characteristic diagram showing changes in the diffraction intensity of a platinum thin film when the mixing ratio of oxygen in argon is changed. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Zhi1°) (bnZo(')

Claims (3)

[Claims] (1) In the process of producing a metal thin film by sputtering, the first process involves forming the metal thin film in an argon gas atmosphere containing 5% or more oxygen by volume, and the second process forming the metal thin film in an atmosphere containing only argon gas. 1. A method for producing an oriented metal thin film, characterized in that: (2) The thickness of the metal thin film formed in the first process is 3
2. The method for producing an oriented metal thin film according to claim 1, wherein the metal thin film has a thickness of 0 to 300 Å and is made of gold or platinum. (3) A method for producing an oriented metal thin film according to claim 2, wherein the metal thin film of gold or platinum is oriented in the <100> direction on the {100} plane of semi-crystalline magnesium oxide. .