JPS58116739A - Controlling method for particle size of film polycrystal - Google Patents

Abstract

PURPOSE:To control the particle diameter of film polycrystal by applying ion injection technique to the acceleration of forming crystalline nuclei in an amorphous material. CONSTITUTION:Crystalline nuclei formation accelerating substance which is made of elements except the component elements of an amorphous material is ion implanted to many specific regions which are predetermined in film amorphous material. Then, it is first heated at the sufficiently low temperature lower than the crystal nuclei forming temperature TN of the amorphous material, thereby forming crystal nuclei only in the specific region. Thereafter, it is subjected to secondary heat treatment at the crystal growing temperature TC of the amorphous material, thereby growing the cyrstal with the nuclei as centers of the specific region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the particle size of a long crystalline film obtained by heat treatment of a film amorphous material. The feature of this method is that before the heat treatment step for crystallizing the amorphous material, ions of a substance effective for forming crystal nuclei are implanted in advance at the location where crystal nuclei are to be formed. Substances to which the method of the present invention can be applied include all crystalline solid substances such as inorganic substances other than organic substances (ionic bonding crystals, covalent bonding crystals), Hankinho, Jinkaede, etc.
The film thickness range to which the method of the present invention can be applied is approximately 0.0
It is 1 μm to 100 μm.

A first object of the present invention is to provide a method by which the size of each crystal grain of a long film crystal can be adjusted to a desired size.

A second object of the present invention is to make all crystal grains of a long film crystal material substantially the same size and approximately 0.01 μm to 10 μm.
Thick film and thin film polycrystalline materials such as magnetic materials, dielectric materials, piezoelectric materials, resistors, and conductive materials, which can be freely selected within the particle size range of 0 μm, are used as functional materials for various sensors, electronics, energy conversion, It has been put into practical use in some areas related to life science, and is expected to be used more widely in the future. It is known that the functions and properties of these materials strongly depend on the size of the crystal grains of the polycrystalline materials that constitute them.

However, a method for freely controlling the size of crystal grains has not yet been established.

Hitherto, for example, epitaxial growth with a substrate, heat treatment conditions, grain growth using additives, etc. have generally been carried out, but in this case grain size control has only been carried out on an average basis. That is, the shape of the particle size distribution of the entire sample is uniquely determined by the manufacturing method and cannot be changed freely. Of course, it was not possible to freely change the particle size depending on the location in the sample, and it was also not possible to make the particle size uniform throughout the sample with high precision.

By the way, ion implantation technology has been developed with the main purpose of controlling the impurity level of 111 degrees in semiconductors, and currently this technology is being applied to optical glass to create guiding waveguides and to control the easy axis direction of magnetization of magnetic bubble domains. , and its application to surface treatment of gold maple materials has been attempted.

The present invention consists of a long crystalline process by applying ion implantation techniques to promote crystal nucleation in amorphous bodies.

(1) Preparation of amorphous film.

(2) Ion implantation of a crystal nucleating substance.

(3) Heat treatment for crystallization.

First, regarding the production of an amorphous film in process (1), conventionally known methods can be applied to this process. Examples include synthesis methods from the gas phase such as sputtering deposition, vacuum evaporation, and chemical vapor deposition (CVD), and synthesis methods from the liquid phase such as ultra-quenching of a melt.

The next process (2) is a process in which a crystal nucleating substance is ion-implanted into the amorphous film having a thickness of 100 to 100 μm prepared by these conventional methods. Here, as the ion implantation technique, an ion implantation method that has been conventionally used for controlling impurities in semiconductors can be applied. Here, as the ions to be implanted, ions of a substance that promotes crystal nucleation during crystallization of the amorphous film are used. In other words, TN is the temperature at which the amorphous film itself forms crystal nuclei by heat treatment, and TN1 is the temperature at which the amorphous body in the region into which the crystal nucleation promoting substance is injected forms crystal nuclei by heat treatment. Then, an ion of a substance that creates the relationship T Nt (TN The size of the region, that is, the specific region into which ions are to be implanted, basically needs to be at least the minimum size at which the generated crystal nuclei can stably exist (although it varies depending on the material, it is usually said to be several dozen). Also, the size of the region to be ion-implanted is 10
If the number exceeds 0.00, the probability that a large number of crystal nuclei will occur in that region increases, crystal growth becomes complicated, and this is not preferable for particle size control. Usually, if the size is within several hundred, the number of crystal nuclei generated in that region is single or multiple. All grain sizes of the polycrystalline material can be made uniform. Note that in order to make the grain size of the entire polycrystalline body uniform, it is necessary to make the geometrical arrangement of specific regions into which ions are to be implanted uniform. That is, it is necessary that the distances between adjacent specific regions are all equal, and preferably that the arrangement of the specific regions has a six-fold symmetry axis perpendicular to the film surface. Of course, specific regions can also be scattered in the depth direction of the film, and in this case, it is necessary that the specific regions are arranged in a close-packed relationship. Under these conditions, by further changing the distance between adjacent specific regions, the grain size of the polycrystalline material finally obtained can be made approximately equal to the distance between adjacent specific regions. By controlling the geometrical arrangement of the region to be ion-implanted in this way, it is possible to uniformly and freely design the grain size of the film-length crystal finally obtained after heat treatment. I can do it. Another great feature of the present invention is that the size of crystal grains can be changed depending on the location in the film.

Furthermore, heat treatment for crystallization in process (3) is performed. TN is the crystal nucleation temperature of the crystalloids.

If the temperature at which the crystal nucleation rate in a specific region into which ions are implanted is the maximum is TNI, then as shown in Figure 1, the crystal growth temperature of the diaphragm crystalloid is 'r'cs. 1 heat treatment Ai is performed, and then the temperature is rapidly raised to the temperature Tc, held at the temperature of Tc, and a second heat treatment B is performed.Here, the temperature of the first heat treatment A, that is, T
It is desirable that the temperature of TNI is sufficiently lower than that of N, and that the temperature difference TN-TN is 50° C. or more. The purpose of the first heat treatment AP is to cause crystal nucleation to occur only in a specific region into which a crystal nucleating substance is ion-implanted, without causing crystal nucleation to occur in the entire crystalline substance. That is, by the first heat treatment A, crystal nuclei are formed only in a specific region of the crystalloid. Continuing, from a temperature well below TN (e.g. TNI)
The temperature is rapidly raised to c, in order to prevent the formation of crystal nuclei in the exfoliated crystalloids outside the specific region. For this reason, it is necessary to rapidly pass around the temperature TN.

The purpose of the second heat treatment B is to uniformly grow crystals centering on the crystal nuclei in each specific region generated in the first heat treatment A. The time required for the second heat treatment B to completely convert the entire film into a polycrystalline material is determined by the crystal growth rate determined by the substance and the designed particle size (distance between specific regions). If the second heat treatment B is stopped within the time required for complete crystallization, a film of a crystalline/amorphous mixture can be obtained, and the amount of amorphous between crystal grains can be reduced. Second
It can be arbitrarily adjusted by changing the treatment time of heat treatment B.

Examples of the method of the present invention will be described in detail below.

An example of a metal material is the magnetic Go-Zr alloy, an example of a semimetal material (covalently bonded crystal) is the semiconductor St, and an example of an oxide material (a crystal with strong ionic bonding) is the ferroelectric material B a Ti Os. We conducted experiments using each of them.

Example 1 A 0090%-2rl0% alloy was melted and ultra-quenched to produce an amorphous film with a thickness of 12 μm. The crystal nucleation temperature (TN) of this crystalloid is 470'C, and the crystal growth temperature (TO) is 650C. This amorphous film was fixed on a high melting point glass substrate, cut into a size of 11IIXII x 111I11, the surface of the film was masked using a mask method commonly used in the manufacture of semiconductor integrated circuits, and electron beam etching was performed as shown in Figure 2. Hole C with diameter 300 as shown
A geometrical arrangement was formed with equal distances of 16 μm. Thereafter, Cu ions were accelerated at a high voltage and ion implantation was performed. The amount of ion implantation was 10 atoms/cc. The maximum depth of the Cu ion concentration distribution in the depth direction was 2 μm from the film surface. In addition, the crystal nucleation temperature (TN, ) of the specific region into which Cu ions were implanted is Co9
The crystal nucleation temperature (TN) of the 0%-10% Zr amorphous material itself was 470'C, which was 360°C, about 100°C lower. In addition to Cu, Au is used as a crystal nucleating substance for the CO-based Kinho amorphous material.

Aq etc. were effective. The thus obtained product was heat-treated at a temperature of 650° C. for 1 hour, and then cooled to room temperature. As a result of observing the obtained film surface and the inside of the film after polishing, the particle size (diameter) was 16 μm.
It was a two-dimensional polycrystalline film consisting of uniform particles of m±1 μm.

Example 2 Commercially available amorphous silicon film (thickness: 10 μm), 1 M
A sample '#+ with a size of 1 mm was cut out and used as a sample of a crystalloid. The crystal nucleation temperature (TN) due to annealing of this St amorphous material was about goo°C, and the crystal growth temperature (TO) was about SOO°C. This crystalloid sample was masked in the same manner as in Example 1, and a hole with a diameter of 300 mm was made using the electron beam resist method to define a specific region into which ions were to be implanted. The geometrical arrangement of the specific regions was the same as that in FIG. 2, but the distance between the specific regions (300 etched holes in diameter) was 10 μm. In the sample obtained in this way, B
Ions were implanted. The implantation amount was 10 atoVcc, and the position showing the maximum concentration in the depth direction was 2 μm from the surface. The implantation distance in the depth direction is determined by the accelerating voltage, but with improved performance of experimental equipment in the future, it will be possible to implant ions to a depth of 10 μm or more.

The crystal nucleation temperature due to annealing in the specific region into which B ions are implanted is extremely low, 50°C. In addition to B, P (approximately 160'C
) + As (330℃), etc. The thus obtained amorphous Sf after B atom implantation t-first 60
C. for 10 hours, then rapidly heated to 800.degree. C. (126.degree. C./second), and heat-treated at a temperature of soo.degree. C. for 1 hour. As a result of observing the surface and interior of the obtained film sample using an electron microscope, it was found to be a two-dimensional polycrystalline film consisting of uniform particles with a grain size of 1 opm to 1 μnt.

Example 3 B a T i Oa was sputter-deposited on an alumina substrate at room temperature to produce an amorphous B a T iOs film having a film thickness of O.S μm. The crystal nucleation temperature (TN) due to annealing of this amorphous material was about sso°C, and the crystal growth temperature (TQ) was about 850°C. This amorphous film is o,
s, x o, s, the surface thereof was masked in the same manner as in Example 1, and holes with a diameter of 100 mm were made using the electron beam resist method to define specific regions for ion implantation. In addition,
The geometrical arrangement of the specific areas was the same as in FIG. 2, but the spacing between the specific areas (etched holes with a diameter of 100) was 1 μm. Eight ions were implanted into the sample thus obtained. The injection volume was 10 ” at am/cc and p1
The position showing the maximum concentration in the depth direction is 0.36 μm from the surface
It was there. The crystal nucleation temperature by annealing of the specific region into which As ions were implanted was 470-C. A8
The amorphous BaTi0a after pouring was first heated and held at 470°C for 3 hours, and then rapidly heated (66°C) from that temperature to 850°C.
°C/sec), heated and maintained at a temperature of 860 °C for 10 minutes, and then cooled to room temperature. As a result of observing the surface and inside of the obtained membrane sample with an electron microscope, the particle size was 0.06 to 1 μm.
It was a two-dimensional polycrystalline film consisting of uniform particles of μm.

As described above, according to the method of the present invention, a long crystal body in which individual crystal grains have uniform sizes can be easily produced with extremely good reproducibility.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a heating schedule for implementing the method according to the present invention, and FIG. 2 is a diagram showing an example of the arrangement of regions into which crystal nucleation substances are to be ion-implanted. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure double opening No. 2r11 00'-0O000 o o Oo Oo.

Claims (1)

[Scope of Claims] 0) After ion-implanting a crystal nucleation promoting substance consisting of a constituent element other than the constituent elements of the amorphous body into a large number of predetermined specific regions in the film amorphous body, the above-mentioned A first heat treatment is performed at a temperature sufficiently lower than the crystal nucleation source 1 (TN) of the amorphous body to first generate crystal nuclei only in the specific region, and then the crystal growth temperature (TN) of the amorphous body is A method for controlling the grain size of a film strip crystal, characterized by performing a second heat treatment at Tc) to grow crystals centered on the crystal nuclei in the specific region. (2) A method for controlling the particle size of a film strip crystalline material according to claim 1, characterized in that the entire region of the film amorphous material is crystallized in the second heat treatment. 2. In the heat treatment, first, rapid heating is performed in a temperature range from a temperature sufficiently lower than the crystal nucleation temperature (T1) of the amorphous body to the crystal growth temperature (TC) of the amorphous body, and then the above-mentioned Crystal growth temperature (Tc) K of amorphous material
(4) The size of a predetermined number of specific regions in the film amorphous body is 10
The geometrical arrangement of the specific areas according to claim 1, characterized in that the distances between the center points of the specific areas that are close to each other are all equal, and 2. The method for controlling the grain size of a membrane strip crystal according to claim 1, wherein the center point has a six-fold axis of symmetry perpendicular to the membrane surface. (6) In the first heat treatment, the temperature is sufficiently lower than the crystal nucleation temperature (TN) of the amorphous material, at which temperature the crystal nucleation rate within the specific region after ion implantation becomes maximum. 2. The method of controlling the grain size of a long crystalline material according to claim 1, wherein the temperature (TN.) is controlled.