Evaporation source device

Abstract

To allow realization of an evaporation source device capable of yielding an evaporation material having high reactivity and ensuring reduction of defects in film composition.SOLUTION: An evaporation source device 100 includes: a source chamber 101 that is divided by a partition wall 131 into a material sublimation chamber 110, in which an evaporation material 105 is heated to produce material vapor, and a plasma reaction chamber 120, in which the material vapor is plasma-processed and delivered toward a deposition object; a heating unit 115 configured to heat the material sublimation chamber 110; a high-frequency circuit 125 for exciting plasma within the plasma reaction chamber 120; and gas piping 127 adapted to introduce a carrier gas into the plasma reaction chamber 120. The partition wall 131 is provided with an orifice 132, through which the material vapor is introduced into the plasma reaction chamber 120.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to evaporation source devices, and more particularly to evaporation source devices that can be used for vapor deposition of chalcogen elements. [Background technology]

[0002] In recent years, thin films containing chalcogen elements such as sulfur (S), selenium (Se), and tellurium (Te) have attracted attention as light-absorbing materials. For example, the use of copper-indium-selenium (CIS) or copper-indium-gallium-selenium (CIGS) as a light-absorbing layer is expected to lead to solar cells with high conversion and absorption efficiencies and resistance to degradation over time. Furthermore, tin sulfide (SnS) is expected to be a promising material for solar cells that does not contain rare metals or harmful elements.

[0003] CIGS thin films can be formed by selenization or multi-source evaporation. However, selenization requires the use of toxic hydrogen selenide. For this reason, multi-source evaporation, in which selenium is deposited together with other elements by sputtering, has attracted attention. However, because selenium has a relatively low reactivity, it is more likely to adhere to the inner walls of the chamber than to deposit on the surface of the substrate or the like. For this reason, evaporation source devices equipped with a chimney that guides selenium vapor from the evaporation source to the substrate have been investigated in order to efficiently deliver selenium vapor to the substrate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-270363 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if a chimney is installed, selenium tends to adhere to the inner wall of the chimney, making it difficult to stably deliver selenium to the substrate. Furthermore, selenium vapor has low reactivity and a high vapor pressure, so even if it reaches the substrate, it does not easily diffuse into the film and tends to re-evaporate, which can lead to defects in the film composition.

[0006] Chalcogen elements other than selenium have similar properties to selenium, and similar problems occur when depositing SnS, etc. Furthermore, similar problems can occur with other elements, not just chalcogen elements.

[0007] An object of the present disclosure is to realize an evaporation source device that can obtain a highly reactive evaporation material and is less likely to cause defects in the film composition. [Means for solving the problem]

[0008] One aspect of the evaporation source device disclosed herein comprises a source chamber partitioned by a partition wall into a material sublimation chamber that heats an evaporation material to generate material vapor, and a plasma reaction chamber that converts the material vapor into plasma and sends it toward a film formation target; a heating unit that heats the material sublimation chamber; a high-frequency circuit that generates plasma in the plasma reaction chamber; and a gas supply unit that supplies a carrier gas to the plasma reaction chamber, wherein the partition wall has an orifice through which the material vapor is supplied from the material sublimation chamber to the plasma reaction chamber.

[0009] One aspect of the evaporation source device has a source chamber partitioned by a partition wall into a material sublimation chamber that heats an evaporation material to generate material vapor and a plasma reaction chamber that activates the material vapor and sends it toward a film-forming target. The material vapor is supplied from the material sublimation chamber to the plasma reaction chamber through an orifice. This prevents the material vapor from solidifying before it is converted into plasma. The plasma-converted material vapor can be sent with directionality toward the film-forming target, allowing for the deposition of a high-quality thin film with few defects on the surface of the film-forming target.

[0010] In one aspect of the evaporation source device, the gas supply section can have a pipe that passes through the material sublimation chamber and reaches the plasma reaction chamber.

[0011] In one aspect of the evaporation source device, the source chamber can have a cover provided on the opposite side of the plasma reaction chamber from the partition wall and having an outlet.

[0012] In one embodiment of the evaporation source device, the evaporation material can contain a chalcogen element.

[0013] In one embodiment of the evaporation source device, the carrier gas can be an inert gas. [Effects of the Invention]

[0014] According to the evaporation source device of the present disclosure, a highly reactive evaporation material can be obtained, and a high-quality thin film can be formed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing an evaporation source device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] An evaporation source device 100 according to one embodiment can be installed in the chamber of a vacuum evaporation device as an evaporation source of the vacuum evaporation device. As shown in Fig. 1, the evaporation source device 100 includes a source chamber 101 having a material sublimation chamber 110 and a plasma reaction chamber 120 separated by a partition wall 131. The partition wall 131 is provided with an orifice 132 that connects the material sublimation chamber 110 and the plasma reaction chamber 120.

[0017] The material sublimation chamber 110 is the portion from the base end of the source chamber 101 to the partition wall 131. The material sublimation chamber 110 can be heated by a heating unit, and can sublimate the deposition material 105 contained therein to generate material vapor. In this embodiment, the heating unit is a heater 115 disposed around the material sublimation chamber 110. The heater 115 is driven by a driving unit and heats the material sublimation chamber 110 to a predetermined temperature. The heater 115 and the material sublimation chamber 110 are housed in a heat-insulating container 141 so that the temperature of the material sublimation chamber 110 can be efficiently maintained at the predetermined temperature.

[0018] The plasma reaction chamber 120 is the portion of the source chamber 101 from the partition wall 131 to the lid 135 at the tip. The plasma reaction chamber 120 is provided with a high-frequency circuit and a gas supply unit, and is capable of generating plasma inside. In this embodiment, the high-frequency circuit has a high-frequency coil 125 disposed outside the plasma reaction chamber 120. High-frequency power is supplied to the high-frequency coil 125 by a control unit. The gas supply unit has a gas pipe 127 and a gas inlet 153 that supply a carrier gas into the plasma reaction chamber 120. A gas cylinder or the like is connected to the gas inlet 153 via a valve and a flow rate control unit.

[0019] The material vapor generated in the material sublimation chamber 110 moves through the orifice 132 to the plasma reaction chamber 120. The material vapor is mixed with a carrier gas in the plasma reaction chamber 120 and converted into plasma. The material vapor, which has been converted into plasma and is now in a highly activated state, is sent out from the outlet 136 provided in the lid 135 and supplied to the surface of the substrate on which a film is to be formed.

[0020] When the material sublimation chamber and the plasma reaction chamber are separate and connected by a connecting pipe, the connecting pipe needs to be heated to prevent the material vapor from solidifying and clogging the connecting pipe. If a valve is provided in the connecting pipe to control the supply amount of material vapor, clogging is likely to occur at the valve even when the pipe is heated.

[0021] In the evaporation source device 100 of this embodiment, a single source chamber 101 is separated into a material sublimation chamber 110 and a plasma reaction chamber 120 by a partition wall 131. Because the material sublimation chamber 110 and the plasma reaction chamber reach high temperatures, the partition wall 131 between them is also efficiently heated to a sufficiently high temperature. Therefore, there is almost no risk of the material vapor solidifying and depositing on the surface of the partition wall 131, and even if the material sublimation chamber 110 and the plasma reaction chamber 120 are connected by a small-diameter orifice 132, there is very little risk of clogging. By supplying the material vapor from the material sublimation chamber 110 to the plasma reaction chamber 120 through the small-diameter orifice 132, the supply amount of the material vapor can be appropriately controlled without installing a valve. The supply amount of the material vapor can also be changed by adjusting the temperature of the material heating chamber.

[0022] The temperature of the plasma reaction chamber 120 is maintained at a high temperature by heat radiation from the material sublimation chamber 110 and heat generated by plasma generation. Furthermore, the material vapor, which has been converted into plasma together with the carrier gas and is in a state of highly active radicals and ions, is less likely to solidify, so solidification of the material vapor hardly occurs within the plasma reaction chamber 120. Furthermore, the plasma-converted material vapor is discharged from the outlet 136 together with the carrier gas, improving its directivity toward the substrate and increasing the amount of material vapor that reaches the substrate. Furthermore, the plasma-converted material vapor is highly reactive, so the proportion that contributes to film formation on the substrate surface also increases. Therefore, even in the case of chalcogen elements such as selenium and sulfur, defects are less likely to occur in the film composition, allowing for the deposition of high-quality thin films.

[0023] The gas supply unit that supplies the carrier gas can have various configurations for supplying the gas into the plasma reaction chamber 120. For example, in this embodiment, a gas pipe 127 that passes through the outside of the source chamber 101 is provided to supply the carrier gas from the side of the plasma reaction chamber 120, but the gas pipe can also be housed inside the source chamber 101. By passing the gas pipe inside the source chamber 101, the device can be made more compact.

[0024] The carrier gas is not particularly limited, but is preferably an inert gas that does not affect the material vapor. Among them, argon is preferred because it is easy to handle and can be easily converted into plasma.

[0025] In the evaporation source device 100 of this embodiment, the evaporation material 105 is not particularly limited. However, chalcogen elements such as sulfur (S), selenium (Se), and tellurium (Te) offer significant advantages, including improved substrate accessibility, improved reactivity on the substrate surface, reduced consumption, and reduced deposition within the chamber, which were not possible with conventional evaporation source devices. By supplying chalcogen elements using the evaporation source device 100 of this embodiment, high-quality CIGS films, SnS films, ZnS, CuS, and WS2 films with minimal compositional defects can be efficiently formed. Multiple evaporation source devices can be used to supply multiple types of material vapor during film formation. Furthermore, the deposition method can be combined with various physical vapor deposition or chemical vapor deposition techniques, such as sputtering, pulsed laser deposition (PLD), resistance heating, and electron beam evaporation. Furthermore, the deposition of chalcogen elements on the chamber inner surface can be significantly reduced, simplifying chamber maintenance.

[0026] The heating unit can have various configurations that can heat the material sublimation chamber 110 to a temperature suitable for the deposition material. When the deposition material is selenium or sulfur, it is preferable that the material sublimation chamber 110 can be heated to about 500°C.

[0027] The size of the source chamber 101 can be appropriately selected depending on the required supply capacity of material vapor. In this embodiment, the inner diameter is approximately 40 mm and the length is approximately 200 mm. In this embodiment, the source chamber 101 has an inner cylinder inserted into the tip end of the outer cylinder, with the base end of the outer cylinder serving as the material sublimation chamber 110 and the inner cylinder serving as the plasma reaction chamber 120. This configuration allows for easy cleaning and the replenishment or replacement of the deposition material 105 by removing the inner cylinder. The materials for the inner and outer cylinders can be selected depending on the deposition material and can be made of, for example, quartz or a corrosion-resistant metal. The portion of the inner cylinder exposed to plasma is preferably made of a material with excellent heat resistance and plasma resistance, such as quartz or pyrolytic boron nitride (PBN). The outer cylinder can be made of the same material as the inner cylinder, or a different material. The partition wall 131 can be integrated with the inner cylinder or can be separate.

[0028] The source chamber 101 is not limited to this configuration and can have other configurations. For example, the material sublimation chamber 110 and the plasma reaction chamber 120 can be formed separately, and the two components can be connected later to form the source chamber 101. In this way, the material sublimation chamber 110 and the plasma reaction chamber 120 can be easily formed from different materials. Furthermore, if the material sublimation chamber 110 and the plasma reaction chamber 120 are separable, the evaporation material 105 can be easily replenished or replaced.

[0029] In this embodiment, the outlet 136 is provided at the center of the lid 135. This increases the directivity of the plasma-converted material vapor and improves the stability of plasma generation. However, the position and number of the outlets 136 can be changed as needed. Also, the lid 135 can be omitted, and the front end of the plasma reaction chamber 120 can be open.

[0030] In this embodiment, a rotary shutter 138 is provided on the extension line of the outlet 136. This physically blocks the supply of plasma-converted material vapor to the substrate. The shutter 138 may be provided as needed.

[0031] In this embodiment, a housing 104 is provided to house the source chamber 101. The housing 104 is cylindrical and has an opening 137 at its tip. By housing the source chamber 101 in the housing 104, the evaporation source device 100 can be easily installed as a single unit in various vacuum chambers. In addition, a base 143 of the housing 104 is provided with a connector 151 for supplying power to the heater 115, a connector 152 for supplying high-frequency power to the high-frequency coil 125, a gas inlet 153 for supplying gas to the gas pipe 127, a shutter driver 154 for driving the shutter 138, and the like. [Industrial Applicability]

[0032] The evaporation source device of the present disclosure provides a highly reactive evaporation material capable of forming a high-quality thin film, and is useful in the production of various semiconductor material films, etc. [Explanation of symbols]

[0033] 100 Evaporation source device 101 Source Chamber 104 Housing 105 Evaporation materials 110 Material sublimation chamber 115 Heater 120 Plasma Reaction Chamber 125 High Frequency Coil 127 Gas Pipe 131 Bulkhead 132 Orifice 135 Lid 136 Outlet 137 Opening 138 Shutter 141 Heat-shielding container 143 Base 151 Connector 152 Connector 153 Gas inlet 154 Shutter drive unit

Claims

1. a source chamber partitioned by a partition wall into a material sublimation chamber for heating a deposition material to generate material vapor, and a plasma reaction chamber for converting the material vapor into plasma and sending it toward a film formation target; a heating unit that heats the material sublimation chamber; a high frequency circuit for generating plasma in the plasma reaction chamber; a gas supply unit that supplies a carrier gas to the plasma reaction chamber; the partition has an orifice; The material vapor is supplied from the material sublimation chamber to the plasma reaction chamber through the orifice.

2. 2. The evaporation source device according to claim 1, wherein the gas supply unit has a pipe that passes through the material sublimation chamber and reaches the plasma reaction chamber.

3. 2. The evaporation source device according to claim 1, wherein the source chamber is provided on the opposite side of the plasma reaction chamber from the partition wall, and has a cover having an outlet.

4. The evaporation source device according to claim 1 , wherein the evaporation material includes a chalcogen element.

5. The evaporation source device according to claim 1 , wherein the carrier gas is an inert gas.

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