Vacuum deposition method

Abstract

To provide a vacuum deposition method capable of laminating multiple vapor-deposited films with a predetermined quality in a short time.SOLUTION: A vacuum deposition method of laminating multiple vapor-deposited films on a substrate surface includes the steps of: arranging, in a vacuum deposition apparatus, a substrate, a vapor deposition metal of a vapor deposition material to be vapor-deposited on the substrate surface, and a vacuum degree accelerating metal for accelerating a vacuum degree in the vacuum deposition apparatus, and evacuating an inside of the vacuum deposition apparatus to a predetermined vacuum degree; forming a vapor-deposited film of a first layer by vapor-depositing the vapor deposition metal to the substrate surface; vaporizing the vacuum degree accelerating metal by heating in vacuum; evacuating the inside of the vacuum deposition apparatus to the predetermined vacuum degree again; and forming a vapor-deposited film of a second layer on a surface of the vapor-deposited film of the first layer by vacuum depositing the vacuum deposition metal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vacuum deposition method. [Background technology]

[0002] One of the methods for measuring the impurity levels of a semiconductor substrate is the DLTS method (Deep Level Transient Spectroscopy). In the DLTS method, a Schottky electrode is formed on the surface of the substrate and an Ohmic electrode is formed on the back surface to form a Schottky barrier diode, and the deep levels in the depletion layer are evaluated. When evaluating the electrical characteristics of a semiconductor substrate, a Schottky electrode is formed on the surface of the substrate and an Ohmic electrode is formed on the back surface, as in the DLTS method, and a voltage is applied to evaluate the dielectric breakdown voltage, forward characteristics, etc. The metal electrodes used in this evaluation method are formed using a vacuum deposition device.

[0003] It is known that in order to form a good Schottky junction, it is preferable that the difference in work function between the substrate and the metal electrode is large, and it is widely known that, for example, aluminum, Au, Pt, etc. are used for N-type silicon single crystal. Also, a high vacuum is necessary to form a high-quality evaporated film using a vacuum evaporation device. Patent Document 1 describes how, when a vacuum container is made from aluminum or an aluminum alloy, it is possible to easily achieve a deposition rate of 1×10 by baking at a relatively low temperature (about 120°C) for several hours. -5 It is described that an ultra-high vacuum of less than 1 Pa can be obtained, and that when deposition is performed under this pressure by electron beam heating, a defect-free thin film with excellent crystallinity can be obtained.

[0004] In addition, a method of improving the degree of vacuum by combining multiple vacuum pumps is widely known. For example, a turbo molecular pump and an ion pump can be combined to achieve a vacuum of 1×10 -10 It is possible to achieve ultra-high vacuum of Pa.

[0005] Patent Document 2 describes that by heating a heating substance during evacuation to raise the temperature inside the vacuum container, unnecessary gases already adhering to the inner wall of the vacuum container can be released and exhausted, and a more desirable vacuum state can be created when the deposition substance is heated for deposition.

[0006] Patent Document 3 describes that in a vacuum deposition method, when the deposition material is evaporated, the pressure inside the device drops.

[0007] Patent Document 4 describes that the evaporation material supplied to a vacuum evaporation apparatus can be preliminarily subjected to acid washing and / or additionally subjected to vacuum heating or atmospheric heating to release moisture contained in the evaporation material, thereby reducing the amount of gas released from the vacuum evaporation material.

[0008] Patent document 5 describes a method for forming a high-quality film by isolating the surface to be deposited from a vacuum atmosphere, evacuating the vapor deposition material while evaporating the vapor deposition material, turning the vacuum atmosphere into a high vacuum state, and then exposing the surface to be deposited to the vacuum atmosphere from which the vapor deposition material is evaporating. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 7-138739 [Patent Document 2] JP 2009-041071 A [Patent Document 3] Japanese Patent Application Publication No. 04-099266 [Patent Document 4] JP 2000-087221 A [Patent Document 5] Japanese Patent Application Publication No. 08-120442 Summary of the Invention [Problem to be solved by the invention]

[0010] It is known that in order to form a good Schottky junction, it is preferable that the work function difference between the substrate and the metal electrode is large. For example, as a Schottky electrode for an N-type silicon single crystal, it is preferable to use Pt because of the magnitude of the work function and the stability of the metal film. However, Pt has a high melting point, and it takes a very long time to form a thick film even by electron beam heating, which is not practical. It is also preferable to use Au, but when Au is evaporated onto a silicon (Si) substrate, Si and Au diffuse into each other and deteriorate over time, so it is not stable over the long term. Therefore, we investigated a method to form a Schottky electrode that combines multiple metals in a short time and with good quality.

[0011] By first depositing a thin layer of Pt and then forming another Schottky electrode (e.g., Au or aluminum), it was found that the work function is estimated to be smaller than that of a single layer of Pt, but the deposition time and the cost of deposition materials (also called deposition source) can be significantly reduced and a good Schottky electrode can be obtained. However, when forming a multi-layer deposition film, there was a problem that the degree of vacuum was significantly deteriorated due to outgassing during the deposition process of the first layer. Therefore, it was necessary to wait a long time until the degree of vacuum improved before depositing the second layer.

[0012] The above-mentioned Patent Documents 1 and 2 do not disclose a method for removing gas (outgas) that is released into the deposition chamber during the deposition process of the first layer and reduces the degree of vacuum. Patent Document 3 describes controlling the heating of aluminum, which is the deposition material, based on information on pressure changes, and does not describe using a deposition material other than aluminum to form multiple deposition films to form Schottky junctions. The method of Patent Document 4 has problems caused by pretreatment, such as an increase in the number of processing steps for the evaporation material and oxidation of the deposition material due to the reaction of the chemical solution with the deposition material. Patent Document 5 does not disclose a method for improving the degree of vacuum that has deteriorated during the deposition process of the laminated film. In addition, the deposition material must be continuously blown off until the degree of vacuum is improved, which is a problem in that a larger amount of deposition material is required than is necessary for deposition.

[0013] Furthermore, when a plurality of vacuum pumps are combined, the ion pumps need to be baked in advance, which poses the problem that they are not suitable for quickly removing gases newly generated during the deposition process.

[0014] The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and has an object to provide a vacuum deposition method capable of laminating a plurality of deposited films of predetermined quality in a short period of time. [Means for solving the problem]

[0015] The present invention has been made to solve the above-mentioned problems, and provides a vacuum deposition method for stacking a plurality of deposition films on a substrate surface, the method including the steps of: arranging a substrate, a deposition metal for deposition material to be deposited on the substrate surface, and a vacuum promotion metal for promoting the degree of vacuum in the vacuum deposition apparatus within a vacuum deposition apparatus; evacuating the inside of the vacuum deposition apparatus to a predetermined degree of vacuum; vacuum-depositing the deposition metal on the substrate surface to form a first layer of deposition film; vacuum-heating the vacuum promotion metal to evaporate it; again evacuating the inside of the vacuum deposition apparatus until a predetermined degree of vacuum is reached; and vacuum-depositing the deposition metal on the surface of the first layer of deposition film to form a second layer of deposition film.

[0016] In this vacuum deposition method, first, the substrate is evacuated to a predetermined vacuum level before the first layer of deposition film is formed on the substrate surface, so that the first layer of deposition film can be of a predetermined quality. Next, during the process of forming the first layer of deposition film, gases emitted (outgassing) from the deposition material, moisture, etc. float in the vacuum deposition apparatus and adhere to the wall of the vacuum deposition apparatus, causing the vacuum level in the vacuum deposition apparatus to deteriorate. However, when the vacuum level promoting metal is evaporated in the next process by vacuum heating, the evaporated vacuum level promoting metal can react with the gases emitted from the deposition material remaining in the vacuum deposition apparatus, moisture, etc., and can be removed, so that the vacuum level can be improved in a short time. Therefore, by evacuating in the next process, the vacuum deposition apparatus can be reliably brought to a predetermined vacuum level, and the time required for evacuating to reach the predetermined vacuum level can be shortened. Furthermore, the second layer of deposition film is formed at a predetermined vacuum level in the next process, so that the second layer of deposition film can be of a predetermined quality. As described above, two layers of deposition films of a predetermined quality can be laminated in a short time.

[0017] Furthermore, after the step of forming the second layer of vapor deposition film, it is preferable to repeat at least once the steps of vacuum heating the vacuum promoting metal to evaporate it, drawing a vacuum inside the vacuum vapor deposition apparatus until a predetermined vacuum level is reached, and vacuum-depositing the vapor deposition metal onto the surface of the vapor deposition film of the previous layer to form a vapor deposition film of the next layer.

[0018] Such a vacuum deposition method makes it possible to laminate three or more layers of deposited films of a desired quality in a short period of time.

[0019] In addition, to form the second and subsequent layers of evaporated films, the cycle can be repeated in which a vacuum-promoting metal that promotes the vacuum level is evaporated by vacuum heating before forming the evaporated film, the inside of the vacuum evaporation apparatus is evacuated to a specified vacuum level, and the next evaporated film is then formed by vacuum evaporation.

[0020] In addition, in the process of evaporating the vacuum-promoting metal by vacuum heating, it is preferable to separate a space having the substrate from a space having the vacuum-promoting metal so that the vacuum-promoting metal is not deposited on the surface of the substrate.

[0021] By separating the space containing the substrate from the space containing the vacuum-promoting metal in this manner, when the vacuum-promoting metal evaporates, the vapor of the vacuum-promoting metal diffuses only into the space containing the vacuum-promoting metal, promoting the degree of vacuum, while the vapor of the vacuum-promoting metal does not diffuse into the space containing the substrate, preventing the vacuum-promoting metal from being deposited on the surface of the substrate.

[0022] It is also preferable that a plurality of different deposition metals are used, and the junction structure between the substrate and a plurality of deposition films stacked on the surface of the substrate is a Schottky junction formed by combining thin films of the plurality of different deposition metals.

[0023] If the junction structure between the substrate and a plurality of evaporated films stacked on the substrate surface in this way is a Schottky junction, it can be used to measure the impurity levels of the substrate and evaluate its electrical characteristics.

[0024] It is also preferable that the vacuum promoting metal is aluminum or an aluminum alloy.

[0025] Aluminum or aluminum alloys have a low melting point in a vacuum, so they can be evaporated stably even at relatively low temperatures. In addition, because the melting point is low, the heating time required to reach the melting point can be shortened, and the power required for heating can also be reduced. Furthermore, because aluminum or aluminum alloys are inexpensive materials, costs can also be reduced.

[0026] In addition, the predetermined vacuum level is 9×10 -5 It is preferable to set the pressure to 0.1 Pa or less.

[0027] Vacuum level 9 x 10 -5 If the pressure is set to 0.1 Pa or less, a vapor-deposited film of good quality can be formed.

[0028] More preferably, the degree of vacuum is 5×10 -5 In this case, a deposition film of higher quality can be formed. In addition, 1×10 -5 By creating an ultra-high vacuum of 100 Pa or less, it is possible to obtain a thin film of even higher quality, with excellent crystallinity and no defects. Effect of the Invention

[0029] According to the vacuum deposition method of the present invention, first, the substrate is evacuated to a predetermined vacuum level before the first layer of deposition film is formed on the substrate surface, so that the first layer of deposition film can be of a predetermined quality. Next, during the process of forming the first layer of deposition film, gases emitted (outgassing) from the deposition material, moisture, etc. float in the vacuum deposition apparatus and adhere to the wall of the vacuum deposition apparatus, causing the vacuum level in the vacuum deposition apparatus to deteriorate. However, when the vacuum level promoting metal is evaporated in the next process by vacuum heating, the evaporated vacuum level promoting metal can react with the gases emitted from the deposition material remaining in the vacuum deposition apparatus, moisture, etc., and can be removed, so that the vacuum level can be improved in a short time. Therefore, by evacuating in the next process, the vacuum deposition apparatus can be reliably brought to a predetermined vacuum level, and the time required for evacuating to reach the predetermined vacuum level can be shortened. Furthermore, the second layer of deposition film is formed at a predetermined vacuum level in the next process, so that the second layer of deposition film can be of a predetermined quality. As described above, two layers of deposition films of a predetermined quality can be laminated in a short time. [Brief description of the drawings]

[0030] [Figure 1] 1 is a flowchart of a vacuum deposition method according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing an example of a vacuum deposition apparatus used in the vacuum deposition method of the present invention. [Diagram 3] 4 is a flowchart of a vacuum deposition method according to another embodiment of the present invention. [Figure 4] 1 is a graph showing experimental results of an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will be described in detail below, but the present invention is not limited thereto.

[0032] As described above, there has been a demand for a vacuum deposition method capable of laminating a plurality of deposited films of predetermined quality in a short period of time.

[0033] As a result of extensive research into the above-mentioned problems, the inventors have discovered that when forming a second or subsequent layer of vapor deposition film, it is necessary to quickly reach a predetermined degree of vacuum by removing the released gas and moisture from the vapor deposition material generated when forming the vapor deposition film of the previous layer, and that an effective way to achieve this is to vacuum-heat a vacuum-promoting metal that promotes the degree of vacuum, thereby completing the present invention.

[0034] That is, the vacuum deposition method of the present invention is a vacuum deposition method for laminating multiple deposition films on the surface of a substrate, and includes the steps of arranging a substrate, a deposition metal for deposition material to be deposited on the substrate surface, and a vacuum promotion metal for promoting the degree of vacuum in the vacuum deposition apparatus in a vacuum deposition apparatus, evacuating the inside of the vacuum deposition apparatus to a predetermined degree of vacuum, vacuum-depositing the deposition metal on the substrate surface to form a first layer of deposition film, vacuum-heating the vacuum promotion metal to evaporate it, again evacuating the inside of the vacuum deposition apparatus until a predetermined degree of vacuum is reached, and vacuum-depositing the deposition metal on the surface of the first layer of deposition film to form a second layer of deposition film.

[0035] In particular, by having a process of evaporating a vacuum-promoting metal by vacuum heating between the process of forming the first layer of the evaporated film and the process of forming the second layer of the evaporated film, the evaporated vacuum-promoting metal can react with and remove released gases and moisture from the evaporated material remaining in the vacuum evaporation apparatus, thereby improving the degree of vacuum in a short period of time.

[0036] It is preferable to apply the process of evaporating this vacuum-promoting metal by vacuum heating not only between the processes of the first and second layers, but also between the processes of the second and third layers, etc., each time a multi-layer vapor deposition film is formed.

[0037] On the other hand, it is not necessarily required before the process of forming the first layer of the evaporated film. In fact, before forming the first layer of the evaporated film, there may be no gas or moisture released from the evaporation material, and the initial vacuuming of the vacuum evaporation device may be set to last for a relatively long time. For example, the vacuum level may be set to 9×10 -5 Pa or less, more preferably 5×10 -5 It is also possible to reduce the pressure to below 1 Pa and then form the first layer of the deposited film by vacuum deposition. Therefore, it is not necessarily necessary to vacuum-heat the vacuum-promoting metal before forming the first layer of the deposited film. However, if a deposited film has been formed on another substrate using the same vacuum deposition device before the step of forming the first layer of the deposited film, and there is a possibility of residual released gas or moisture, a step of vacuum-heating and evaporating the vacuum-promoting metal may be provided.

[0038] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0039] Fig. 1 is a flow chart of a vacuum deposition method according to a first embodiment of the present invention, and Fig. 2 is a schematic diagram showing an example of a vacuum deposition apparatus used in the vacuum deposition method according to the present invention. As shown in Fig. 1, the vacuum deposition method according to the first embodiment is composed of steps S1 to S5.

[0040] (Step S1) Step S1 is a process of placing a substrate, a metal for deposition of the deposition material to be deposited on the substrate surface, and a vacuum promotion metal for promoting the degree of vacuum within the vacuum deposition apparatus in a vacuum deposition apparatus, and evacuating the inside of the vacuum deposition apparatus to a predetermined degree of vacuum.

[0041] First, the substrate to be used as the sample is placed in the sample holder 1 in Fig. 2, and the metal for deposition to be deposited first on the substrate surface, the metal for deposition to be deposited as the second layer, and the vacuum promoting metal for promoting the degree of vacuum are placed in any of the boats (boat 2 for electron beam heating, boats 3 and 4 for resistance heating). When the metal to be deposited is Pt, electron beam heating is essential, but when aluminum is used, it can be evaporated sufficiently by resistance heating, so either electron beam heating or resistance heating can be used.

[0042] After that, evacuation is performed until a predetermined degree of vacuum is reached. The degree of vacuum at this time is not particularly limited since it depends on the performance of the sample, the device, and the vacuum pump, but is preferably 9×10 -5 Pa or less, more preferably 5×10 -5 Pa or less.

[0043] In this case, the substrate to be used as the sample is not particularly limited, but a silicon substrate or a substrate with 3C-SiC formed on a silicon substrate is processed to a size (MAX 5cm square) that can be set in the sample holder 1 and set.

[0044] Next, the vacuum system is rough-evacuated using the roughing pump 5. The roughing pump 5 used here is not particularly limited as long as it can evacuate to a degree of vacuum that allows for main evacuation with the turbomolecular pump 6, but considering contamination due to oil diffusion from the pump, it is preferable that the roughing pump 5 is a scroll pump that does not use oil. After reaching a degree of vacuum that allows for main evacuation, main evacuation is performed with the turbomolecular pump 6.

[0045] (Step S2) Step S2 is a process of forming a first layer of a deposition film by vacuum-depositing the deposition metal on the surface of the substrate.

[0046] The deposition method and film thickness are not particularly limited, but the deposition method can be electron beam heating, and the film thickness is not particularly limited, but can be, for example, 10 nm. In this deposition process, gas released (outgassing) from the deposition material and moisture float in the device and adhere to the device wall.

[0047] (Step S3) Step S3 is a process of evaporating the vacuum promoting metal by vacuum heating.

[0048] The vacuum enhancing metal can be aluminum or titanium, which has an adsorptive effect, but aluminum or an aluminum alloy is most preferred because of its low melting point in vacuum and low cost.

[0049] The heating method is not particularly limited, but can be, for example, resistance heating. The evaporation rate and time are not particularly limited, but can be preferably 3 Å / s, and can be 10 seconds or more. The evaporation rate is calculated by not particularly limited, but a film thickness monitor using a quartz crystal oscillator 7 can be used. By controlling the evaporation rate in this way, it can be efficiently reacted with the gas released from the deposition material and moisture present in the device.

[0050] When the vacuum promoting metal is evaporated in a vacuum, the evaporated vacuum promoting metal reacts with the gas released from the deposition metal of the deposition material, moisture, etc., improving the degree of vacuum. According to the description in Patent Document 5, this is because gas in the vacuum atmosphere, such as carbon dioxide gas (CO2, CO, etc.), water (H2O), oxygen (O2), etc., is adsorbed to the deposition material and exhausted. The "deposition material" in Patent Document 5 corresponds to the evaporated vacuum promoting metal in this embodiment, and the "gas in the vacuum atmosphere" corresponds to the gas released from the deposition metal, moisture, etc. Therefore, in this embodiment, the gas released from the deposition metal, moisture, etc. are adsorbed to the evaporated vacuum promoting metal and exhausted as exhaust 8, improving the degree of vacuum.

[0051] By improving the degree of vacuum here, it is possible to shorten the evacuation time required to reach a high degree of vacuum in the subsequent evacuation step (step S4).

[0052] At this time, by closing the shutter 11 with respect to the shielding plate 9 in Fig. 2, the space 12 containing the substrate and the space 13 containing the vacuum promoting metal are separated so that the vaporized vacuum promoting metal does not deposit on the substrate surface. This shutter 11 is not of a completely isolating type, but has a non-sealing structure in which a disk larger than the opening of the shielding plate 9 blocks the opening of the shielding plate 9, but the vacuum promoting metal does not deposit on the substrate surface when the shutter 11 is closed. In addition, because there is a gap between the shielding plate 9 and the shutter 11, the space 12 containing the substrate can be evacuated with the shutter 11 closed. This reliably prevents deposition on the substrate except during deposition.

[0053] As a result, when the vacuum promoting metal evaporates, the vapor of the vacuum promoting metal diffuses only into the space 13 containing the vacuum promoting metal, promoting the degree of vacuum, and the vapor of the vacuum promoting metal does not diffuse into the space 12 containing the substrate, preventing the vacuum promoting metal from being deposited on the substrate surface. As a result, a high-quality deposited film can be formed.

[0054] It should be noted that the vacuum enhancing metal may also be used as the vacuum enhancing metal in the deposition of another substrate, provided that it is not completely evaporated.

[0055] Furthermore, if the metal for deposition is the same metal as the vacuum promoting metal (for example, aluminum), the metal for deposition can serve as both the metal for deposition and the vacuum promoting metal, making it possible to reduce the number of types of metal and boats.

[0056] (Step S4) Step S4 is a process of again evacuating the inside of the vacuum deposition apparatus until a predetermined degree of vacuum is reached.

[0057] The heating in step S3 is stopped, and with the shutter 11 closed, a vacuum is drawn through the gap between the shielding plate 9 and the shutter 11 until a predetermined vacuum level is reached. Since the vacuum level is improved in step S3, the predetermined vacuum level can be reliably reached, and the time required for vacuum drawing to reach the predetermined vacuum level can be shortened.

[0058] (Step S5) Step S5 is a process of opening the shutter 11 and vacuum-depositing the deposition metal on the surface of the first deposition film to form a second deposition film.

[0059] The heating method for forming the second layer of the evaporated film is not particularly limited, but can be resistance heating, and although not particularly limited, the heating time can be, for example, 20 seconds and the film thickness can be 6 nm.

[0060] Since the predetermined degree of vacuum is achieved in step S4, the second layer of the deposited film can be formed at the predetermined degree of vacuum, and the second layer of the deposited film can be of a predetermined quality.

[0061] As a result, two layers of evaporated films of predetermined quality can be laminated in a short period of time.

[0062] Next, another embodiment of the present invention will be described with reference to the drawings.

[0063] Fig. 3 is a flow chart of a vacuum deposition method in another embodiment of the present invention. The vacuum deposition method in this embodiment shows an example in which a third layer and subsequent layers are formed, and is different from Fig. 1 of the first embodiment in steps S5' and S6. Here, the points different from the first embodiment will be described.

[0064] (Step S5') Step S5' is a process for forming a vapor-deposited film similar to step S5 in FIG. 1, but since not only the second layer but also the third layer and subsequent layers are formed, it is called "formation of the next vapor-deposited film."

[0065] (Step S6) Step S6 is a process of returning to step S3 after step S5', and repeating steps S3, S4, and S5' an arbitrary number of times. The first step S5' is a process for forming a second layer of evaporated film, as in Figure 1, and then returning to step S3, the second step S3 is a process for evaporating the vacuum-promoting metal by vacuum heating, the second step S4 is a process for drawing a vacuum inside the vacuum evaporation apparatus until a predetermined vacuum level is reached, and the second step S5' is a process for vacuum-evaporating the evaporation metal onto the surface of the evaporated film of the previous layer (the second layer in this case) to form an evaporated film of the next layer (the third layer in this case), and it is preferable to repeat this process one or more times.

[0066] With this type of vacuum deposition method, after forming a deposited film in step S5', the degree of vacuum is improved in step S3, the evacuation time is shortened in step S4, and the next deposited film is formed in step S5'. This process is repeated, so that three or more layers of deposited films of the specified quality can be stacked in a short period of time. EXAMPLES

[0067] The present invention will be described in detail below with reference to examples. However, these examples are given for illustrative purposes and should not be construed as limiting.

[0068] [Example 1] Referring to Fig. 2, first, a silicon single crystal substrate measuring 5cm square was set on a sample holder 1, and Pt, the metal for deposition to be deposited on the substrate surface as the first layer, was placed in an electron beam heating boat 2, Au, the metal for deposition to be deposited on the substrate surface as the second layer, was placed in one resistance heating boat 3, and aluminum, the metal for promoting the degree of vacuum, was placed in the other resistance heating boat 4. Then, a scroll pump 5 and a turbo molecular pump 6 were used to create a vacuum of 5 x 10 -5 The initial evacuation was carried out for about 16 hours until the pressure dropped below 1 Pa.

[0069] Next, the first layer was vacuum-deposited. The vacuum level at the start of deposition was 3.9×10 -5 The deposition pressure was 1.2 × 10 Pa. The deposition material, Pt metal, was deposited by electron beam heating. The deposition rate was about 0.2 Å / s, and 10 nm was deposited. Due to outgassing from the deposition material, the degree of vacuum after deposition was 2.2 × 10-4 It worsened to Pa.

[0070] Next, the vacuum-promoting metal, aluminum, was heated and evaporated by resistive heating at a rate of 3 Å / s for 20 seconds.

[0071] Next, heating was stopped and evacuation was continued. At this time, the vacuum level was 9×10 -5 It took less than 10 seconds for the pressure to reach 5×10 Pa. -5 The time it took to reach Pa was 107 seconds.

[0072] After that, the second layer was vacuum-deposited. The deposition metal was Au, and the deposition method was resistance heating. The deposition rate was about 4 Å / s, and 100 nm was deposited.

[0073] [Comparative Example 1] First, a silicon single crystal substrate measuring 5 cm square was set on the sample holder 1, and the deposition metal Pt for the first layer to be deposited on the substrate surface was placed in the electron beam heating boat 2, and the deposition metal Au for the second layer to be deposited on the substrate surface was placed in one of the resistance heating boats 3. No vacuum promoting metal aluminum was placed. Then, the vacuum level was increased to 5×10 using the scroll pump 5 and turbo molecular pump 6. -5 The initial evacuation was carried out for about 16 hours until the pressure dropped below 1 Pa.

[0074] Next, the first layer was vacuum-deposited. The vacuum degree at the start of deposition was 4.2×10 -5 The deposition pressure was 1.0 Pa. The deposition material, Pt metal, was deposited by electron beam heating. The deposition rate was about 0.2 Å / s, and 10 nm was deposited. Due to outgassing from the deposition material, the degree of vacuum after deposition was 3.7×10 -4 It worsened to Pa.

[0075] After that, the vacuum was continued, but the vacuum level was 9 x 10 -5 It took 815 seconds for the vacuum to reach 8.6×10 Pa. Vacuuming was continued for 15 minutes, but the vacuum level was still 8.6×10-5 Pa, and 5×10 -5 I couldn't get it to Pa.

[0076] Therefore, the second layer was vacuum-deposited under conditions of a lower degree of vacuum than in Example 1. The deposition metal of the deposition material was Au, and the deposition method was resistance heating. The film formation rate was about 4 Å / s, and 100 nm was deposited.

[0077] The results of Example 1 and Comparative Example 1 are summarized in Table 1 below and FIG.

[0078] [Table 1]

[0079] The specified vacuum level is 9 x 10 -5 Comparing the time to reach the pressure in Pa, it was less than 10 seconds in Example 1, whereas it took as long as 815 seconds in Comparative Example 1. This is believed to be mainly because Example 1 of the present invention includes a step of evaporating the vacuum-promoting metal by vacuum heating (step 3 in Figs. 1 and 3), whereas the conventional Comparative Example 1 does not include this step. As described above, it was found that Example 1 of the present invention was able to laminate a plurality of vapor-deposited films of a predetermined quality in a shorter time than the conventional Comparative Example 1.

[0080] In addition, in Example 1, the vacuum level was reduced to 5×10 in 107 seconds. -5 Pa or less, and a deposition film of higher quality can be formed.

[0081] The present invention includes the following aspects. [1]: A vacuum deposition method for laminating a plurality of deposition films on a substrate surface, comprising the steps of: A step of disposing a substrate, a metal for deposition of a deposition material to be deposited on a surface of the substrate, and a vacuum promoting metal for promoting a degree of vacuum in the vacuum deposition apparatus in a vacuum deposition apparatus, and evacuating the inside of the vacuum deposition apparatus to a predetermined degree of vacuum; forming a first layer of a deposition film by vacuum-depositing the deposition metal on the surface of the substrate; Vacuum heating the vacuum enhancing metal to evaporate it; a step of again drawing a vacuum in the vacuum deposition apparatus until a predetermined vacuum level is reached; forming a second layer of the deposited film by vacuum-depositing the deposition metal on a surface of the first layer of the deposited film; A vacuum deposition method comprising the steps of: [2]: After the step of forming the second layer of the vapor deposition film, Vacuum heating the vacuum enhancing metal to evaporate it; a step of drawing a vacuum inside the vacuum deposition apparatus until a predetermined vacuum level is reached; forming a deposition film of a next layer by vacuum-depositing the deposition metal on a surface of the deposition film of the previous layer; The vacuum deposition method according to the above [1], characterized in that the above step (a) is repeated one or more times. [3]: The step of evaporating the vacuum promoting metal by vacuum heating includes: The vacuum deposition method according to [1] or [2] above, characterized in that a space having the substrate and a space having the vacuum promoting metal are separated from each other so that the vacuum promoting metal is not deposited on the surface of the substrate. [4]: The vacuum deposition method according to any one of the above items [1] to [3], characterized in that a plurality of different deposition metals are used, and a junction structure between the plurality of deposition films stacked on the surface of the substrate and the substrate is a Schottky junction combining thin films of the plurality of different deposition metals. [5]: The vacuum deposition method according to any one of the above [1] to [4], wherein the vacuum promoting metal is aluminum or an aluminum alloy. [6]: The specified vacuum level is 9×10 -5 The vacuum deposition method according to any one of the above [1] to [5], characterized in that the vacuum deposition pressure is set at 0.1 Pa or less.

[0082] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any configuration that is substantially the same as the technical idea described in the claims of the present invention and that provides similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0083] 1...sample holder; 2...electron beam heating boat; 3, 4...resistance heating boat; 5...Roughing pump (scroll pump), 6...Turbo molecular pump, 7...quartz crystal oscillator; 8...exhaust; 9...shielding plate; 11...shutter; 12: Space having a substrate; 13: Space having a vacuum promoting metal. S1, S2, S3, S4, S5, S5', S6... steps.

Claims

1. A vacuum deposition method for laminating a plurality of deposition films on a substrate surface, comprising the steps of: A step of disposing a substrate, a metal for deposition of a deposition material to be deposited on a surface of the substrate, and a vacuum promoting metal for promoting a degree of vacuum in the vacuum deposition apparatus in a vacuum deposition apparatus, and evacuating the inside of the vacuum deposition apparatus to a predetermined degree of vacuum; forming a first layer of a deposition film by vacuum-depositing the deposition metal on the surface of the substrate; Vacuum heating the vacuum enhancing metal to evaporate it; a step of again drawing a vacuum in the vacuum deposition apparatus until a predetermined vacuum level is reached; forming a second layer of the deposited film by vacuum-depositing the deposition metal on a surface of the first layer of the deposited film; A vacuum deposition method comprising the steps of:

2. After the step of forming the second layer of the vapor-deposited film, Vacuum heating the vacuum enhancing metal to evaporate it; a step of drawing a vacuum inside the vacuum deposition apparatus until a predetermined vacuum level is reached; forming a deposition film of a next layer by vacuum-depositing the deposition metal on a surface of the deposition film of the previous layer; 2. The vacuum deposition method according to claim 1, wherein the above steps are repeated one or more times.

3. The step of evaporating the vacuum promoting metal by vacuum heating includes:

3. The vacuum deposition method according to claim 1, wherein the space having the substrate and the space having the vacuum promoting metal are separated from each other so that the vacuum promoting metal is not deposited on the surface of the substrate.

4. 3. The vacuum deposition method according to claim 1 or 2, characterized in that a plurality of different deposition metals are used, and a junction structure between the substrate and a plurality of deposition films stacked on the surface of the substrate is a Schottky junction formed by combining thin films of the plurality of different deposition metals.

5. 3. The vacuum deposition method according to claim 1, wherein the vacuum promoting metal is aluminum or an aluminum alloy.

6. The predetermined vacuum level is 9×10 －５ 3. The vacuum deposition method according to claim 1, wherein the pressure is set to 0.1 Pa or less.

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