JPH11195397A - Low energy heavy ion three-dimensional radiation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify device constitution, and implant ions three-dimensionally to a material of a solid phase at a room temperature. SOLUTION: An ion material 1 is placed in a microwave chamber 5, and it is vaporzed by a laser beam 2 to generate gas plasma 3. The plasma 3 is diffused around an ion target material 4, plasma density and pulse width are adjusted to prevent arc discharge induced between the material 4 and the plasma 3, a DC pulse high voltage is applied between the plasma 3 at a negative potential and the target material 4, and heavy ions are implanted to the whole material surface. Appication of the laser beam 2 and the DC pulse high voltage is repeated and overlapped to increase ion implantation dosage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial application] Ion implantation is widely used in the semiconductor industry, and directly modifies the surface of other materials, for example, mechanical properties such as corrosion resistance and wear resistance, and electrical and thermal properties such as heat transfer and insulation. Modification of properties, improvement of chemical properties such as adsorption and surface activity, improvement of optical properties such as reflection and polarization, interfacial treatment of composite materials, non-thermal equilibrium impurity implantation, pretreatment of thin film coating, spattering and etching, etc. It has begun to be used in a wide range of fields.

[0002]

2. Description of the Related Art It has become practically feasible to convert a gas-phase substance into a high-current ion beam at room temperature such as hydrogen by diverting nuclear fusion technology. However, many ion beam raw materials required for material development are solid at room temperature. Therefore, in a general heavy ion implantation method, (a) a source material is vaporized in an oven or by sputtering, and then a source plasma is generated by (b) arc discharge or the like. After that, (c) the beam is generated and accelerated by the electrostatic field, (d) target ions in the beam are discriminated from the discharge sustain gas ions using an electromagnetic field, and (e) the process of injecting ions into the sample Have been. But,
Although the beam current value depends on the ion species, it is as small as several μA to several mA, and the beam cross-sectional area is small. Therefore, an effective irradiation dose of 10 ¹⁶ cm ⁻³ is effective for material surface modification using ion implantation.
In order to carry out over the entire material surface, a long irradiation time such as several tens of hours was required. In addition, due to the relationship between added value and cost, industrial use of ion beams outside the semiconductor industry is extremely limited compared to electron beams, despite the various physicochemical properties of ions.

[0003]

In the conventional heavy ion beam implantation method, three-dimensional irradiation requires operations such as moving and rotating a control object. Therefore, (a) the beam formation and the ion species discrimination process of the conventional ion implantation apparatus are omitted to simplify the apparatus configuration. Furthermore, (2) a new type of low-energy heavy ion implantation with a simple structure and high efficiency, in which ion implantation can be performed three-dimensionally on the surface of the ion implantation material, omitting the beam scanning and the process of moving the irradiation object. The task was law development.

[0004]

In order to solve the above-mentioned problem (a), the generation of implanted ions is vaporized by laser light without using a discharge assisting gas such as an inert gas for generating a source plasma of an ion beam source. And ECR discharge. In order to solve the problem (b), the ion implantation target material is placed in a plasma containing the implanted ions without forming the implanted ions into a beam, and a short period of time such that an arc discharge is not induced between the plasma and the target material. It is characterized in that a pulse voltage having a width is applied to implant ions three-dimensionally on the material surface.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION When a heavy ion source material (1) placed in a MW chamber (5) of FIG. 1 is vaporized by a laser beam (2), MW (microwave) previously introduced into the MW chamber is obtained.
And an electromagnetic coil (8 to 15) installed outside of the same room and a strong magnetic field, an ECR discharge is generated and M
W plasma (3) is generated. By applying a high-voltage direct-current short pulse to the ion target material (4) using the seed plasma as an anode while the plasma does not disappear, the source ions are three-dimensionally spatially pulsed onto the ion target material. It can be implanted with an energy of about 10 keV or less. The applied voltage is several tens of kV or less, and the application time width is set short enough not to cause an arc discharge between the plasma and the material. The irradiation of the laser beam and the high voltage application process are repeatedly superimposed to increase the ion implantation dose. The potential of the seed plasma with respect to the ion implantation target is determined by the potential of the plasma electrode (7) provided inside the ion implantation chamber or inside the chamber so as to face the target material (4). Therefore, ion implantation for the target is performed in a three-dimensional space.

[0006]

Embodiment 1 FIG. 1 shows an embodiment in which a plurality of MW chambers are provided, and heavy ion plasma generated therefrom is diffused and collected in a large-capacity ion implantation chamber to be used as seed plasma for ion implantation of a large material. Indicated.

[0007]

Embodiment 2 The MW chamber and the ion implantation chamber are integrated.

[0008]

Embodiment 3 A seed plasma is generated using a vacuum arc.

[0009]

Embodiment 4 Vaporization of an ionized raw material is performed using an electric oven.

[0010]

According to the conventional ion implanter, the implantation energy is too high, around 200 keV, and the ion concentration distribution becomes unsuitable for surface modification. In the implantation method of the present invention, since the implantation energy is limited to several tens keV or less, there is an effect that accumulation of the implantation dose on the outermost surface is quick. In this method, the space charge density of the seed plasma is low,
Since the energy distribution of implanted ions is wide, the non-uniformity of the implanted ions in the depth direction due to the remarkable increase in ion density near the range as in the conventional ion implantation method is reduced, and the This has the effect of equalizing in the direction. Even when a conventional ion implanter apparatus is used for surface modification of other materials, the ion species is limited, and even if the effect is exhibited, it is often overlooked. As a result, despite the many physical properties of ion species, there have been few examples of using an ion implanter for material research using ion implantation.
However, if the device of the present invention spreads as a simple, inexpensive, and highly efficient device, the basics of ion beam application and the pioneering of application fields have already been opened, so the expansion of ion beam application fields and industrial application The effect of the present invention on progress is great.

[Brief description of the drawings]

FIG. 1 (Example 1) Two MW chambers are provided in an ion implantation chamber, and heavy ion plasma generated therein is diffused and collected in a large-volume ion implantation chamber to be used as seed plasma to perform ion implantation of a large-sized material. An example of such a case is shown (see FIG. 1 of the attached sheet).

[Explanation of symbols] Ionized material Laser beam MW heavy ion plasma Target material MW (microwave) room
Ion implantation chamber Plasma electrode ▲ 15 ▼ Electromagnetic coil ▲ 16 ▼ Cusp magnetic field ▲ 17 ▼ Vacuum pump ▲ 1
8 ▼ Plasma probe ▲ 19 ▼ High speed shutter

Claims (1)

[Claims] The ionized raw material (1) placed in the MW chamber (5) provided in a part of the vacuum vessel is vaporized by the laser beam (2),
After the generation of the plasma (3), a direct current high voltage short-circuit between the plasma in the ion implantation chamber (6) and the ion target material (4), where the plasma is positive and the ion target material is negative. A heavy ion implantation method in which heavy ions are three-dimensionally implanted into the surface of an ion target material by applying a pulse.
(See Fig. 1)