JPH05170469A - Production of quartz fiber - Google Patents

Abstract

PURPOSE:To work quartz glass fiber of nanometer size by irradiating it with electron beams in an electron microscope. CONSTITUTION:The fiber made by this method has a diameter of several nanometers and a length of several microns and is the thinnest of all the fiber that has been produced. In the production of this fiber, silicon fine particles 1 whose surface is oxidized (composite particles of silicon-oxide) are irradiated with convergent electron beams on their joined parts with each other. The joined part 2 of the particles is deformed and elongated by the irradiation, causing thin quartz fiber to be formed between the particles. Drawing of the fiber is easily controlled by changing the irradiation intensity of electron beams on the joined parts of the particles. The interesting application to optical fiber or semiconductor techniques or structural materials of the next generation is developed by the quartz fiber thus produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing quartz fibers having a diameter of several nanometers or less, which is applicable to optical fiber technology. These ultrafine fibers can also be applied to fine metal-ceramic composite materials and MOS (metal-oxide-semiconductor) devices.

[0002]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an ultrafine quartz transition having a diameter of several nanometers or less.

[0003]

[Means for Solving the Problems] Submicron-sized silicon particles are produced by a vapor deposition method for several hours.
Oxidizes in the atmosphere at 1000 ° C. The surface-oxidized silicon fine particles are composed of silicon nuclei and a uniform outer quartz layer having a thickness of several nanometers. Hereinafter, these are referred to as quartz fine particles for convenience (since the silicon nuclei are in a stable state during observation). The gray oxide powder is composed of many fine quartz particles that are connected by thin bridges (junctions) between them. According to FIG. 1 (a), the uniform irradiation of the particles 1 with an electron beam is performed by filling the joint portion 2 between the particles, thereby sintering the slowly bonded structure (sinteri).
ng) and coagulation. Sintering between any two particles is driven by the reduction in total surface energy and the transfer of material from the region of high vapor pressure (positive curvature) to the interface (negative curvature and therefore low vapor pressure). To be done.

This quartz fiber manufacturing technique is based on the fact that when an electron beam is focused on a joint, the energy (pressure) forms a joint having a higher energy than that of other portions, and the balance is reversed. .. As a result, according to FIG. 1B, the substance flows out from the joint portion to the convex portion on the surface, and the joint portion becomes thin and extends. Initially, the elongation of the bonded portion is dumbbell-shaped having separated particles (FIG. 2 (a)), but when the electron beam is irradiated for a sufficient time, the bonded portion of quartz deformed into long and thin fibrous is formed ( FIG. 2B). The elongation of the bonded portion can be controlled by defocusing the electron beam or lowering the strength. In addition, in FIG. 2B, the black portion visible on the particle is a gold cluster deposited on the surface following the flow and deformation of the joining portion. According to FIG. 3, the fibers thus obtained have a diameter of a few nanometers,
The length will be a few microns.

[0005]

EXAMPLES FIGS. 2 and 3 show electron microscope images of deformed joints and final fibers formed by irradiation for a sufficient time. The results were obtained using an AKASHI transmission electron microscope at 200 keV and a base pressure of 1.
Operated at 0 ^-6 torr and current density of -10 to 100a
It was obtained at mps / cm ² . The rate at which the bond deforms and draws the fiber depends on the actual current density used, but can be easily controlled by beam defocusing. The experimental results are UHV (Ultra H
high Vacuum: Ultra high vacuum (10 ^-10 torr)
r) Microscopically examined and found to be reproducible. The UHV microscope can produce fibers with a smooth surface, which is very useful for practical applications.
Fibers of any glass composition can also be produced by subjecting the quartz outer layer of oxidized silicon particles to a suitable alloying treatment and exposing the joints to irradiation.

The fibers obtained as described above become unstable under intense electron irradiation and break at the surface irregularities formed during irradiation sputter damage (PM Aj).
ayan and S.A. Iijima, Phil. Ma
g. lett. , In press). However, under normal defocused irradiation conditions, the fibers are very stable and can withstand the superposition of numerous quartz particles at their tip. The inventor believes that the strength of the fibers along the fiber axis is equally good, if not better than known quartz fibers. In fact, the surface of the fiber damaged (by sputtering) can be smoothed by exposing the fiber to the defocused electron beam for a sufficient time. Since it removes irregularities on the surface,
This enhances the mechanical strength many times. Thus, according to a typical sequence of forming a reinforced fiber, a focused electron beam is used to draw the fiber to the desired length and expose the fiber to defocused irradiation for a sufficient time to form a smooth surface. Finally, the fiber is finally cut at both ends using a focused electron beam. The strength of the fibers can be improved by coating the fibers with a second phase (coating the glass fibers with a material of different refractive index as an optical waveguide) and also improving the optical properties.

[0007]

The present specification discloses a technique for producing the smallest quartz (glass) fiber ever produced. The fibers produced according to the present invention provide important practical applications in the optical fiber industry where the use of smaller size fibers means higher performance and efficiency of the device. The inventor believes that this technique is useful in better fabrication of finer ceramic fiber structure materials and in oxide semiconductor devices.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the effect of electron beam irradiation on the deformation of the junction between quartz particles, where (a) uniform irradiation gives activation energy for diffusion of atomic species, and as a result, It shows that sintering reduces the total surface area and free energy. (B) Focused electron beam irradiation at the joint produces high energy and unstable joints, from the joint to the convex part of the assembly. It shows that the joint part is elastically deformed by the flow of the substance.

FIG. 2 (a) is a photograph of a TEM image of a deformed joint between two quartz fine particles upon irradiation with a focused electron beam, and FIG. It is a photograph which shows a substantially completely deformed joint between quartz particles.

FIG. 3 is a photograph showing an image of a quartz fiber produced according to the present invention.

[Explanation of symbols]

 1 particle 2 junction

Claims (1)

[Claims] 1. An ultrafine quartz fiber having a diameter of a few nanometers or less is formed by irradiating a focused electron beam to a bonded portion of silicon fine particles whose surfaces are oxidized to deform and extend quartz in the bonded portion. A method for producing a characteristic quartz fiber.