JP2000123778A - Ion implanting device and ion implanting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide a large ion current at a low cost by applying a positive high voltage changed intermittently to an ion generation section in steps, and directly implanting irradiation ions to a substrate section without mass-separating an extracted positive ion beam. SOLUTION: A high-voltage power supply 5 with a voltage control function is connected to a high-purity iron ion source 1, an extracting electrode 2 is set to the ground potential, and an ion current integrating device 6 for measuring the ion implantation ion dose quantity is connected to a Si substrate 3 and grounded. High-frequency power 200 W and spattering DC power 110 W are applied to the high-purity iron ion source 1 to generate Fe ions. The output voltage of the power supply 5 is kept at +100 kV for the first 20 min, at +80 kV for the next 20 min and at +50 kV for the last 35 min. An Fe ion beam 4 having the implantation energy of 100 keV, 80 keV and 50 keV respectively is ion-implanted to the Si substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus, an ion implantation method, and a method for manufacturing a semiconductor device.
Thermoelectric elements that convert thermal energy generated in automobile engines, steelworks, or garbage incineration plants into electrical energy, photoelectric elements that detect or generate light such as infrared light, and solar energy into electrical energy Related to a solar cell for conversion.

[0002]

2. Description of the Related Art Conventionally, as a thermoelectric element, a solar cell, an infrared light detecting element, or an infrared sensor, an element using β-FeSi ₂ crystal, which is a kind of metal silicide having semiconductor properties, has been developed in 1998 (Heisei 10). Proceedings of the 45th JSAP Spring Meeting, Spring 2015, No. 0, lecture number 28p-
ZR-5, page 14; Katsumat
a, HL Shen, N. Kobayashi, Y. Makita, M. Hasegaw
a, H. Shibata, S. Kimura, and A. Obara, Proceeding
s of the Ninth International Conference on Ion Bea
mModifucation of Materials, pp. 943-946 (JS
Edited by Williams, RG Eliman, MC Ridgway, 199
6 years, published by Elsevier) and Y. Maeda, T. Fujit
a, T. Akita, K. Umezawa, K. Miyake, Materials Rese
arch Society Symposium Proceedings, Volume 486, 3
29-334 (edited by A. Polman, S. Coffa, and R. Soref, 1998, published by Elsevier).

In these conventional examples, β-FeSi ₂
As a method for producing a crystal, such as a Freeman ion source,
Using a mass-separation type ion implanter equipped with an ion source of not necessarily high purity,
A multiple ion implantation method in which ions are implanted into an i-substrate a plurality of times is used.

[0004] For example, H. Katsumata, HL Shen, N. Kob
ayashi, Y. Makita, M. Hasegawa, H. Shibata, S. Kimur
a, and A. Obara, Proceedings of the Ninth Internati
onalConference on Ion Beam Modification of Materia
ls, pp. 943-946 (JSWilliams, RG Ellima
n, edited by MC Ridgway, 1996, published by Elsevier
In the first step, an implantation energy of 140 keV and an implantation dose of 1.42 × 10 ¹⁷ i
ons / cm ² , implantation energy of 80 keV and implantation dose of 6.67 × 10 ¹⁶ ions / cm ² in the second stage, implantation energy of 50 keV and implantation dose of 3.83 × 10 ¹⁶ ions / c in the third stage.
It is ion-implanted in m ^2.

Also in the other two reports, when the implantation energy is changed to 100, 50, and 30 keV and the total implantation dose is 1 × 10 ¹⁷ ions / cm ² , β-FeSi _{2 having} good performance is obtained. It is said that crystals are formed.

[0006]

However, in the above-described conventional multiple ion implantation method, since an ion implantation apparatus of a mass separation type is used, equipment such as an electromagnet for mass separation and its control power supply is required. The cost was high and it was difficult to obtain a large amount of ion current. Also,
Since the ion irradiation energy is changed a plurality of times, there is a problem that the process takes a lot of time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ion implantation apparatus and an ion implantation method which can obtain the same effects as those of the conventional multiple ion implantation method with a very simple structure, and to manufacture by this ion implantation method. To provide inexpensive thermoelectric generators, photoelectric devices, and solar cells.

[0008]

An object of the present invention is to dispose at least a positive ion generating section, a positive ion extracting section, and an ion-implanted substrate section in a vacuum, and apply a time-varying positive high voltage to the ion generating section. A positive ion implantation apparatus characterized in that a positive ion beam is applied in a stepwise manner and the extracted positive ion beam is directly irradiated onto the substrate without mass separation, or a negative ion generating unit, a negative ion extracting unit, At least the ion-implanted substrate section is provided, and a mechanism is provided for applying a time-varying negative high voltage to the ion-generating section in a stepwise manner and directly irradiating the extracted negative ion beam to the substrate section without mass separation. This is achieved by a negative ion implantation apparatus characterized in that:

In the present invention, equipment such as an electromagnet for mass separation and its control power supply, which is indispensable in the conventional mass separation type ion implantation apparatus, is not required, so that the apparatus cost is low and a desired large current can be obtained. The ion beam can be easily obtained, and the implantation energy can be changed easily by controlling the high voltage applied to the ion source with a computer program, etc., at the desired timing in terms of time. An ion implantation apparatus capable of manufacturing a semiconductor element with good efficiency can be provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG.
This shows the basic configuration of the present invention, taking the case of producing an eSi ₂ crystal as an example.

A high-purity iron ion source 1 and an extraction electrode 2 are arranged in a vacuum device (not shown) evacuated to a vacuum pressure of 1 × 10 ⁻⁵ Pa. Si (10 mm) with a diameter of 300 mm and a thickness of 400 μm
0) The substrate 3 was arranged. As a high-purity iron ion source 1, K.
Miyake and K. Ohashi, Nuclear Instruments and Metho
ds in Physics Research B121, pp. 102-106 (1
997, published by Elsevier, Inc.), a high-frequency sputtering type iron ion source for generating high-purity iron ions by sputtering a high-purity iron target was used. As a type of the ion beam 4 generated from this high-purity ion source, 95% or more of Fe ions can be obtained, and the remaining amount is β-F
The Ar ions were not harmful for producing eSi ₂ crystals.

A high-voltage power supply 5 with a voltage control function was connected to the high-purity iron ion source 1. The extraction electrode 2 is set to the ground potential,
The i-substrate 3 was connected to an ion current accumulator 6 for measuring the ion implantation ion dose and was grounded.

The high-purity iron ion source 1 is supplied with a high-frequency power 20
0 W and DC power 110 W for sputtering are applied,
Fe ions were generated.

The output voltage of the high voltage power supply 5 with a voltage control function is
As shown in FIG. 2, initially at +100 kV for 20 minutes, then at +80 kV for another 20 minutes and finally at 3 kV.
Maintained at +50 kV for 5 minutes. As a result, the implantation energy on the Si substrate 3 is 100 keV and 80 keV, respectively.
An Fe ion beam 4 of keV and 50 keV was ion-implanted. The Fe ion current value at that time was 100 mA, respectively.
80 mA and 60 mA, and the size of the Fe ion beam 4 on the Si substrate 3 was 350 mm in diameter.

The Fe element distribution in the Si substrate 3 thus implanted with Fe ions was measured by Rutherford backscattering method, and a result as shown by a curve 7 in FIG. 3 was obtained. The vertical axis indicates the dose of the implanted ions, and the horizontal axis indicates the depth. Curves 8, 9, and 10 show the calculated estimated element distributions when the Fe ion beam 4 is ion-implanted alone at implantation energies of 100 keV, 80 keV, and 50 keV, respectively. According to the curve 7 in FIG. 3, the implantation energies of the present invention are 100 keV, 80 keV and 50 keV, respectively.
It can be seen that the element distribution is obtained by triple injection.

The sample in which the Fe ion beam 4 without mass separation is ion-implanted into the Si substrate 3 in this manner is subjected to a lamp annealing heat treatment apparatus for 8 minutes in an Ar atmosphere.
When the lamp was annealed at 00 ° C for 2 hours, the film thickness was 80n.
m polycrystalline β-FeSi ₂ layer was uniformly obtained on the upper portion of the Si substrate 3. The electric conductivity of the polycrystalline β-FeSi ₂ layer was p-type, and the hole mobility was 400 cm ² / Vs at room temperature.

In the present invention, the ion beam is Fe
Triple ions were implanted using ions. Ir, Mn, Cr, Re, Mg, Ba, Ca,
These silicides can also be made using ions such as Os.

When negative ions are used as the type of ions to be implanted, negative ions can be implanted by applying a negative high voltage to the ion source in a stepwise manner.

[Embodiment 2] FIG. 4 is a view showing the configuration of an ion implanter in the case where a laser irradiation type high purity ion source is provided as an ion source in the present invention. The laser irradiation type high-purity ion source is a high-purity ion source placed in a vacuum device (not shown) evacuated to a vacuum pressure of 1 × 10 ⁻⁵ Pa.
(Purity: 99.999%) Passed through the transmission window from the atmosphere through the iron target 11 and collected at a wavelength of 248 nm and an energy of 3
A KrF excimer laser beam 12 having a frequency of 50 mJ
Irradiate in a pulse at 0 Hz to generate an iron plume 13,
The thing of the system which draws out high-purity iron ion beam 4 from there was used.

As in the first embodiment, a high-voltage power supply 5 with a voltage control function was connected to the high-purity iron target 11 in order to change the implantation energy of the implanted ions with time.
The extraction electrode 2 was connected to the ground potential, and the Si substrate 3 was connected to an ion current integrating device 6 for measuring the ion implantation ion dose, and was grounded. As substrate, size 30
A Si (100) substrate 3 having a thickness of 0 mm and a thickness of 400 μm was used.

In the above laser irradiation type high purity ion source,
Since introduction of Ar gas or the like is unnecessary, Fe ions having a high purity of 99.9% or more were obtained.

As in the first embodiment, the output voltage of the high-voltage power supply with voltage control function 5 is changed over time as shown in FIG.
A Fe ion beam 4 of 100 keV, 80 keV, and 50 keV was ion-implanted, and the same result as in Example 1 was obtained.

[Embodiment 3] FIGS. 5 and 6 show that a plurality of substrates 16 are arranged with respect to an ion beam 15 extracted from a high-purity ion generator 14, and the substrates 16 are rotated.
Alternatively, it illustrates the principle of an ion implantation apparatus characterized by performing mechanical scanning by translational motion.

In the case of FIG. 5, the ion beam for implantation 15 radially extracted from the high-purity ion generator 14 is
The three substrates 16 are arranged circumferentially and are rotated at a rotation speed of 10 revolutions per minute to make the implant ion dose distribution uniform. The rotation can be alternately performed to shorten the processing time.

In the case of FIG. 6, three substrates 16 are linearly arranged with respect to the implantation ion beam 15 extracted from the high-purity ion generator 14, and they are reciprocally translated at a rate of three times per minute. And ion implantation is performed to make the implant ion dose distribution uniform.

Embodiment 4 FIG. 7 shows an example of the structure of an infrared light sensor manufactured according to the present invention.

According to the first or second embodiment of the present invention, the Si substrate 3 is formed by the ion implantation apparatus and the ion implantation method of the present invention.
An Al electrode 18 having a thickness of 100 nm was patterned on the p-type β-FeSi ₂ layer 17 formed on the upper substrate by a sputtering method, and an InGa electrode 19 was formed on the back surface. Then, as shown in the figure, a DC bias power supply 20 having a voltage of 1.0 V is connected to an external resistor 21 having a resistance value of 50Ω.
A current was passed through the p-type β-FeSi ₂ layer 17.

When this p-type β-FeSi ₂ layer 17 is irradiated with a pulse of infrared light 22 having a wavelength of 1.06 μm from an Nd + YAG laser (at a frequency of 100 Hz) at room temperature, the current flowing through the external resistor 21 is reduced. When the measurement was performed, a change in which the circuit current increased upon irradiation with light was clearly observed in synchronization with the irradiation with infrared light. That is, it was confirmed that the electric resistance of the β-FeSi ₂ layer 17 was lowered by the photoconductive effect of the infrared light irradiation, and the β-FeSi ₂ layer 17 could be used as an infrared light sensor.

Embodiment 5 FIG. 8 is a view showing an example of the structure of a solar cell manufactured according to the present invention.

In the same manner as in Example 4, the p-type β-
An Al electrode 18 was patterned on the FeSi ₂ layer 17 to form a Schottky junction between the Al film electrode 18 and the p-type β-FeSi ₂ layer electrode 17. InGa electrode 1 on the back
9 was formed, and the metal electrode 23 and the wiring 24 which were in ohmic contact with each other were taken out from the Al film electrode 18, respectively, taken out as a solar cell, and an external measurement circuit 25 was connected.

When the Schottky junction type solar cell having the above structure was irradiated with sunlight 26 (100 mW / cm ² ) in clear weather from above and measured by the external measuring circuit 25, the open-circuit voltage was 0.85V. The short-circuit current was 14.0 mA / cm ² , and the conversion efficiency as a solar cell was 6.8%.

[0032]

As described above, according to the present invention,
It is not necessary to use expensive mass separation electromagnets and its control power source as in the conventional method, and the generated ions are directly implanted into the substrate, so that a large amount of ion current can be easily obtained, and inexpensive. An ion implanter can be provided.

Since the amount and depth of implanted ions can be freely controlled by a high-voltage time program applied to the ion generator, multiple ion implantation can be easily performed.

As a result, a metal silicide material having a semiconductor property that requires multiple ion implantation to produce a high-quality crystal is produced, and a solar cell, a photoelectric device, and a thermoelectric power generation element using them are inexpensive. There is an effect that it becomes possible to provide.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention, taking a case of producing a β-FeSi ₂ crystal as an example.

FIG. 2 is a diagram showing a temporal change of a high voltage applied to an ion generation unit.

FIG. 3. Si measured by Rutherford backscattering method.
FIG. 3 is a diagram showing a Fe element distribution in which triple Fe ions are implanted into a substrate.

FIG. 4 is a diagram illustrating a basic configuration of an ion implantation apparatus including a laser irradiation type high-purity ion source as an ion generation unit.

FIG. 5 shows a plurality of substrates arranged for an ion beam;
It is a figure showing the principle of an ion implantation device characterized by performing mechanical scanning by rotational movement to those substrates.

FIG. 6 shows a plurality of substrates arranged for an ion beam;
FIG. 4 is a diagram showing the principle of an ion implantation apparatus characterized by performing mechanical scanning on these substrates by translational motion.

FIG. 7 is a diagram showing an example of a structure of an infrared light sensor manufactured according to the present invention.

FIG. 8 is a diagram showing an example of the structure of a solar cell manufactured according to the present invention.

[Explanation of symbols]

1. High-purity iron ion source, 2. Extraction electrode, 3. Si
(100) substrate, 4 ... iron ion beam, 5 ... high voltage power supply with voltage control function, 6 ... ion current integrating device, 7 ... Fe element distribution in Si substrate into which multiple Fe ions were implanted, 8 ... 100
Calculated estimated Fe element distribution in Si substrate when Fe ion beam was implanted alone at keV, calculated estimated Fe element distribution in Si substrate when Fe ion beam was implanted alone at 9 ... 80 keV, solely at 10 ... 50 keV Estimated Fe element distribution in Si substrate when Fe ion beam is implanted, 11: high-purity (purity 99.999%) iron target, 12: KrF excimer laser beam, 13: iron plume, 14: high-purity ion generator , 15 ... Ion beam for implantation, 16 ... Substrate, 1
7 ... p-type β-FeSi ₂ layer, 18 ... Al electrode, 19 ... I
nGa electrode, 20: DC bias power supply, 21: external resistance, 22: Nd + YAG laser light having a wavelength of 1.06 μm,
23 ... metal electrode, 24 ... wiring, 25 ... external measurement circuit, 2
6 ... sunlight.

Claims (15)

[Claims] At least a positive ion generating section, a positive ion extracting section, and an ion-implanted substrate section are arranged in a vacuum, and a time-varying positive high voltage is applied to the ion generating section in a stepwise manner. A positive ion implantation apparatus characterized in that a positive ion beam is directly ion-irradiated into a substrate without mass separation. 2. At least a positive ion generating section, a positive ion extracting section, and an ion-implanted substrate section are arranged in a vacuum, and a positive time-varying positive voltage is applied stepwise to the ion generating section and extracted. A positive ion implantation apparatus comprising a plurality of mechanisms for directly irradiating a substrate portion with ion irradiation without mass separation of a positive ion beam. 3. At least a negative ion generator, a negative ion extractor, and a substrate to be ion-implanted are placed in a vacuum, and a time-varying negative high voltage is applied to the ion generator in a stepwise manner. A negative ion implantation apparatus characterized in that a negative ion beam is directly irradiated and ion-implanted into a substrate portion without mass separation. 4. At least a negative ion generator, a negative ion extractor, and a substrate to be ion-implanted are placed in a vacuum, and a negative high voltage that changes with time is applied to the ion generator in a stepwise manner to extract the ions. A negative ion implanter comprising a plurality of mechanisms for directly irradiating a substrate portion with irradiation ions without mass separation of a negative ion beam. 5. At least a positive ion generating section, a positive ion extracting section, and an ion-implanted substrate section are arranged in a vacuum, and a time-varying positive high voltage is applied stepwise to the ion generating section to extract. A mechanism for directly irradiating a positive ion beam onto a substrate without mass separation, and at least a negative ion generator, a negative ion extractor, and a substrate to be ion-implanted in a vacuum, and time-sequentially providing the ion generator. A positive / negative composite ion implantation apparatus characterized in that it comprises both a mechanism for applying a negative high voltage that changes stepwise and irradiating the extracted negative ion beam directly to the substrate without mass separation. 6. The ion according to claim 1, further comprising a sputter-type high-purity ion source of a type in which a high-purity metal is sputtered and ionized as an ion generator. Infusion device. 7. A laser irradiation type high purity ion source according to claim 1, wherein the high purity metal is irradiated with a laser beam to ionize the metal. An ion implantation apparatus characterized by the above-mentioned. 8. The positive or negative positive or negative voltage according to claim 1, wherein different positive or negative high voltages are applied to the ion generating section while being temporally controlled stepwise and applied to the ion generating section. A multiple ion implantation apparatus characterized by performing multiple ion implantation equivalent to an ion implantation dose distribution assumed in advance by directly irradiating ion implantation into a substrate portion without mass separation of an ion beam. 9. The method according to claim 1, wherein a plurality of substrates are arranged for the extracted positive or negative ion beam, and the substrates are mechanically rotated or translated. An ion implantation apparatus for performing scanning. 10. The method of claim 1, 2, 3, 4, 5, 6, or 7.
An ion implantation method using the ion implantation apparatus of 7, 8, or 9, and irradiating the substrate with the extracted positive or negative ion beam without mass separation. 11. An ion implantation method according to claim 10, wherein Fe, Ir, Mn, Cr, Re, Mg, Ba, C
a. A method for producing a silicide compound of these metals having semiconductor properties, which comprises irradiating an ion beam of a or an Os metal onto a Si substrate without mass separation and performing multiple ion implantation. 12. The semiconductor device according to claim 11, wherein said ion implantation method comprises Fe, Ir,
Silicide compounds of Mn, Cr, Re, Mg, Ba, Ca, or Os metal. 13. Fe, Ir, Mn, Cr, Re, M having semiconductor properties produced by the method of claim 12.
A thermoelectric power generation element containing a silicide compound of g, Ba, Ca or Os metal as one of the constituent elements. 14. The semiconductor material of Fe, Ir, Mn, Cr, Re, M having a semiconductor property prepared by the method of claim 12.
An optoelectronic device in which a silicide compound of g, Ba, Ca or Os metal is one of the constituent elements. 15. A semiconductor device having Fe, Ir, Mn, Cr, Re, M
A solar cell comprising a silicide compound of g, Ba, Ca or Os metal as one of the constituent elements.