JPS58119332A - Method and apparatus for vapor deposition - Google Patents

Abstract

PURPOSE:To enable the formation of a vapor deposition film having good film quality, in carrying out vapor deposition in the presence of an activated or ionized modified gas, by discharging, reducing or neutralizing charge capable of being accumulated on a substrate to sufficiently take in the modified gas. CONSTITUTION:A conductive support plate 1 is provided to a substrate 1 in the side of an evaporation source so as to be contacted with the peripheral part thereof and extended to the outside of the substrate 1 or electrically taken out of a bell jar to be grounded. Therefore, if an alpha-Si:H film to be deposited is relatively low in resistance, charge capable of being accumulated during vapor deposition is properly leaked to the side of the support plate 11. By this constitution, the charge amount accumulated on the substrate 1 can be reduced or discharged to be able to prevent repulsing phenomenon of a modified gas such as hydrogen ion and a vapor deposition film sufficiently taking in said ion and excellent in film characteristics can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor deposition method and an apparatus thereof. This a-8i is deposited on a substrate by, for example, a vacuum evaporation method, but at this time, active hydrogen gas is supplied in order to fill the dangling bonds in the a-8i with hydrogen atoms and improve its photosensitivity. In order to control the electrical conductivity of a-8i, dopants such as phosphorus or aluminum may be evaporated and doped into the a-8i.

For example, in a vacuum evaporation apparatus as shown in FIG.
While heating to ℃, θ
It is conceivable to perform vapor deposition by applying a DC bias voltage of ~-10 KV. In the figure, 6 is an introduction pipe for introducing modification gas such as active hydrogen and hydrogen ions, and 7 is an introduction pipe 6 for activating and ionizing modification gas such as hydrogen gas.
A discharge tube 8 provided therein is an exhaust tube and is connected to a vacuum pump (not shown).

By using this device, for example, 1O-4 Tor
Silicon evaporated from the evaporation source 2 under an r-order vacuum is deposited on the substrate 1 as a-8i, and at the same time, active gas from the introduction tube 6 is sucked onto the substrate 1 at a negative potential to deposit a-8i. a-3i (a-8
t:H) can be deposited. Obtained a-8i:
The H film has sufficient dark resistance and light sensitivity, and has uniform film quality with little variation.

In this case, when the substrate 1 is made of an insulating material, the electrode plate 9 is placed on the back side of the substrate 1. If the substrate 1 has conductivity, the negative voltage 5 may be applied directly to the substrate 1. However, as a result of further investigation, the inventor found that there are the following sight points.

That is, especially when an insulating substrate is used as the substrate 1,
At the beginning of vapor deposition, by applying a negative voltage, the electric field of the back electrode 9 attracts the hydrogen ions described above to the substrate 1 side, and it is possible to sufficiently contain hydrogen in the a-8i film and form a homogeneous film, but the vapor deposition progresses a little. As the film thickness of a-3i increases, positive charges due to ions are accumulated on the substrate surface, and thereafter the hydrogen ions are excluded. It is currently unclear whether this charge remains inside the a-8i:H or on its surface, but in any case, it repels the hydrogen ions as shown in Figure 2, and the jL
The hydrogen content of the St film 10 fluctuates (decreases), and in some cases, a discharge may occur within the a-8t:HIG plane and the film may be destroyed. This phenomenon is thought to be due to the positive charges of the hydrogen ions being accumulated on the substrate 1 as the vapor deposition progresses.

In this sense, even if the substrate 1 is vapor-deposited without applying an electric field from the back electrode 9, or if the substrate 1 is made of a conductive substrate without supplying hydrogen ions, a relatively high-resistance material such as a-gi:H can be used. It seems that the same phenomenon can occur as long as a film is deposited. Further, it is considered that the positive charge described above may be partially generated by charged particles existing in the evaporated silicon. Furthermore, when an oxygen-containing film is deposited by introducing another ionized modifying gas, such as oxygen ions, in place of the hydrogen ions, the same charge accumulation phenomenon as described above occurs.

The present invention has been made to correct the above-mentioned problems by releasing or reducing the charge that may accumulate on a substrate during deposition in the presence of an activated or ionized modifying gas. Or, it relates to a vapor deposition method characterized by neutralization. With this vapor deposition method, since no charge is accumulated on the substrate during vapor deposition, the vapor deposited film can be grown while sufficiently incorporating the modifying gas.

In addition, the present invention provides the following steps when carrying out all of the above vapor deposition methods:
Means for discharging, reducing or neutralizing the above-mentioned accumulated charge is attached to the deposition tank, and the means is extended outside the substrate, or is electrically led out to or outside the deposition tank. This paper proposes the use of a vapor deposition apparatus characterized by the following. This vapor deposition apparatus can effectively discharge the accumulated charge to the outside of the vapor deposition tank, or sufficiently reduce or eliminate the charge, so that the vapor deposition method of the present invention can be carried out reliably.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 3 to 7.

Although FIG. 3 shows the substrate and its vicinity according to the first embodiment, the structure of the Pelger itself is basically the same as that shown in FIG. 1, so a description thereof will be omitted.

According to this example, a conductive support plate 11 is provided in contact with (or in close proximity to) the periphery of the substrate 10 on the evaporation source side. This support plate may simply extend outside the substrate 1, or may be electrically led out of the Pelger and grounded. Therefore, in particular, depositing a-8i:
If the H film 10 (actually also adhered on the support plate 11) has a relatively low resistance, positive charges that may be charged up (accumulated) during vapor deposition will leak to the support plate 11 side to an appropriate extent. become. For this reason, the amount of charge accumulated on the substrate 1 can be reduced or released, and the repulsion phenomenon of the modifying gas, such as hydrogen ions, as described above can be prevented, and the film characteristics that sufficiently incorporate the ions can be improved. It becomes possible to form a deposited film with good film quality.

FIG. 4 shows another example, in which a tungsten heater 12 is placed facing the surface of the substrate 1, and the substrate 1 is irradiated with thermoelectrons 14 generated from the heater wire 13 thereof. The heater wire 13 is led out of the Pelger via a lead wire (not shown), and is supplied with voltage from the outside. In addition, 15 is a cover for the heater wire 13, and silicon vapor etc. flying from below can be removed from the heater wire 1.
This prevents it from adhering to 3.

By irradiating the thermoelectrons 14 in this manner, the thermoelectrons 14 are electrostatically attracted by the positive charges that are charged up on the substrate 1 during vapor deposition, and the positive charges can be sufficiently neutralized. ? : Since accumulation of positive charges can be prevented by this, hydrogen ions and the like can be sufficiently attracted onto the substrate 1, and a large amount can be incorporated into the deposited film. In addition, in the structure shown in FIG. 3, when the vapor deposited film 10 has a high resistance, it becomes difficult for electric charges to leak through the support plate 11, but this may be partly due to the use of an insulating substrate as the substrate 1. Conceivable.

In particular, in order to create field effect transistors, photosensors, etc. using a-si:H films, it is necessary to deposit an a-8i:H film on an insulating substrate such as glass. This is a problem in devices. In the faa diagram, since charge can be leaked only from the peripheral portion of the vapor deposited film 10, leakage from other portions becomes insufficient as the resistance of the vapor deposited film 10 becomes high.

To prevent this, the substrate 1 should be made of a conductive material, but this is not possible with the above-mentioned type of element structure, and an insulating substrate must be used, which solves the above problem. I can't.

However, if the configuration is such that the charges are neutralized by thermionic electrons as shown in FIG. However, when positive charges are accumulated on the substrate 1 as the deposition progresses, these positive charges sufficiently attract the thermoelectrons 14 and are neutralized. Therefore, it is possible to neutralize and eliminate positive charges over the entire surface of the vapor deposited film 10, and compared to the structure shown in FIG. Charges can be removed more fully over the entire surface, and hydrogen ions and the like can be contained in the film 10 in large quantities and uniformly.

FIG. 5 shows an example in which the example in FIG. 4 is further improved.

In this example, the thermionic generator 16 is attached to the wall of the Pelger 3.
is incorporated, and thermionic electrons 14 generated from the heater wire 19 of the tungsten heater 18 in the casing 17 outside the Pelger 3 pass through the wall portion of the Pelger 3 from the heater 18 and are lowered to the substrate inside the Pelger 3 by the introduction tube. The light is irradiated in one direction. heater wire 1
The thermoelectrons from 9 are accelerated by a ring-shaped acceleration electrode 21 and introduced into the Pelger 3. heater wire 19
is connected to an AC power supply n, and one end thereof is grounded.

If this thermionic generation device 16 is used, the positive charge on the substrate 1 can be neutralized using the same principle as shown in Figure @4, but the device 16 itself must be installed at a position that does not interfere with the vapor flow of the evaporated substance. Therefore, a more uniform deposited film can be formed compared to that shown in FIG. Moreover, since the heater 18 is located outside the Pel Jar 3, the heater wire 19 is not damaged or deteriorated by the temperature or steam inside the Pel Jar 3, and there is no problem of deterioration of the quality of the deposited film due to evaporation of the heater material.

The thermoelectrons 14 may be deflected by a magnetic field generated by a magnet (not shown), or the thermoelectrons 14 may be accelerated and deflected in combination with the electrode 21.

FIG. 6 shows yet another example.

In this example, an electrode die is provided around the substrate 1 on the evaporation source side, and this electrode die is grounded outside the Pelger. When a photoconductive material such as a-8T:H film 10 is deposited on the substrate 1, light 5 is irradiated onto the substrate 1 from a light source placed inside and/or outside the Pelger. , the vapor deposited film 10 has low resistance due to its conductivity (photoconductor) due to light. As a result, the positive charges existing or accumulated in the membrane 10 become easier to move and are discharged to the ground via the electrode 23, thereby effectively reducing the phenomenon of accumulation of positive charges (i.e., repulsion of hydrogen ions, etc.). can be prevented. In addition to the optical 25Fi lamp, a lamp generated by hydrogen discharge, for example, can be used.

FIG. 7 shows a modification of the example shown in FIG.

That is, instead of providing the electrode 23 shown in FIG. 6, a conductive support plate portion is disposed around the periphery of the substrate 1. In this case as well, the positive charges on the film 10 are moved to the support plate 26 side by the irradiation of the light 5, and are leaked from there to the outside of the substrate 1 (especially the ground), so that accumulation of positive charges can be prevented. Support plate 2
6 needs to be placed so as to be in contact with the deposited film 10 to be deposited, but the film 1 can be moved by minute movement due to rotation, movement, etc.
0 can be contacted. Since the vapor deposition material is deposited on the support plate 26 continuously with the film 10 on the substrate 1, electric charge leaks even through the deposited film on the support plate. In this sense, the support plate does not necessarily have to be electrically conductive; a ground electrode similar to that shown in FIG. 6 may be provided on the support plate, and positive charges may be emitted from this electrode.

In each of the above embodiments, silicon (deposited as amorphous silicon) is used as the semiconductor material to be deposited, and a halogen such as fluorine, which produces the same function as hydrogen, is used as the modifying gas that determines the film properties. Gas or silane may be used. This modifying gas also contains oxygen, nitrogen,
It may consist of one or more selected from the group of phosphine, diborane, arsine, hydrocarbons (eg, halogen gas), ammonia, and the like. In this case, hydrogen and/or -
In addition to halogen-containing amorphous silicon, amorphous silicon oxide, amorphous silicon nitride, amorphous silicon carbide, which have different properties but have desired electrical resistance values, and phosphorus as a donor or acceptor.
Amorphous silicon doped with boron or arsenic can be deposited. In addition, in place of these modifying gases for donors or acceptors, at least one element from Group I and Group V of the periodic table (e.g., phosphorus, aluminum)
The dopant evaporation source may be placed in a vacuum chamber. When this evaporation source is used, hydrogen, halogen, oxygen, nitrogen, hydrocarbon, or ammonia described above is introduced at the same time as a modifying gas, so each amorphous silicon doped with a donor or acceptor is placed on the substrate. can be formed.

In addition, in the above device, since the discharge tube 7 for hydrogen gas, etc. is placed outside the Pel jar 3, there is much less contamination than when it is placed inside the Pel jar 3, and the heat inside the Pel jar during operation is reduced. The electrodes and constituent materials of the discharge tube will not be damaged by water or gas.

Therefore, the degree of freedom in selecting the material of the discharge tube is increased, and the construction and arrangement of the discharge tube can be arbitrarily performed. Also,
The structure of the cooling water pipe (not shown) inside the discharge tube is easy to design, its cooling efficiency is good, and the discharge tube itself can be easily replaced outside the Pelger. However, it goes without saying that the discharge tube may be provided within the Pel jar in terms of feeding the active gas.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, in the charge neutralization method shown in FIGS. 4 and 5, the particles to be irradiated are not limited to thermoelectrons, but may be particles having the opposite polarity to the accumulated charge, and it is also possible to irradiate with radiation. The power source 5 is not limited to the above-mentioned DC power source, but may be an AC power source. Further, the support plate 11 and the support plate 11 in FIGS. 3 and 7 do not necessarily have to be in contact with the substrate IK (in this case, the substrate 1 is supported by another means), and may be provided close to each other. good.

In other words, it does not need to be in contact with the substrate 1 as long as it is in contact with the deposited film. The substrate 1 may of course be made of a conductive material, and in this case a voltage may be applied directly to the substrate. In addition to the above-mentioned E and semiconductors, the substances to be deposited include
Aluminum may be used, in which case oxygen or nitrogen ions can be introduced as modifying gases to form aluminum oxide or aluminum nitride deposits. In addition, various deposition substances and modifying gases can be selected and used.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIG. 1 is a schematic sectional view of a vacuum evaporation apparatus, FIG. 2 is an enlarged sectional view showing the situation in which charge is accumulated during evaporation in the same apparatus, and FIG. 3 4 is a cross-sectional view of a substrate and its vicinity according to an embodiment of the present invention, FIG. 4 is a cross-sectional view similar to FIG. 3 according to another embodiment, and FIG. 5 is a schematic cross-section of a vacuum evaporation apparatus according to yet another embodiment. 6 is a sectional view similar to FIG. 3 according to yet another embodiment, and FIG. 7 is a sectional view similar to FIG. 6 according to a modification of FIG. 6. In addition, in the symbols used in the drawings, 1...
・・・・・・Substrate 2・・・・・・Evaporation source 3・・・・・・Pelger 5・・・・−・・Power source 7・・・・・・・・・Discharge tube 9... Back electrode 10... Vapor deposited film 11.26... Support plate 12.18...・・Heater 13.19・・
......Heater wire 14...Thermionic electron 21...Acceleration electrode n...--Electrode sae... ...Light Source Anger...It is light. Agent Patent Attorney Hiroshi Kakiita Figure 1 Figure 6 θ Figure 7 ○ 187-

Claims (1)

[Scope of Claims] (2) When an evaporation source is heated and evaporated in the presence of an activated or ionized modifying gas to deposit it on a substrate, the charge that may be accumulated on the substrate is released, reduced, or neutralized. A vapor deposition method characterized by a 2. The method according to claim 1, wherein the charge is leaked out of the substrate. 3. The method according to claim 1, wherein the substrate is irradiated with particles of opposite polarity to the charge that can be accumulated on the substrate. 4. The method according to claim 3, characterized in that the particles of opposite polarity are thermoelectrons or radiation. 5. The method according to claim 4, in which thermionic electrons are accelerated and/or deflected by an electric field and/or a magnetic field and then irradiated. 6. A method according to claim 2, in which the deposited layer is photoconductive, in which case the deposited layer is exposed to light. 7. As a modifying gas, hydrogen, −・logen, oxygen, nitrogen,
Any one of claims 1 to 6, characterized by at least one member selected from the group consisting of silane, phosphine, diborane, arsine, hydrocarbon, and ammonia.
The method described in section. 8. The method according to any one of claims 1 to 7, characterized in that a negative voltage is applied to the insulating substrate. 9. An evaporation source, heating means thereof, and a substrate are placed in a deposition tank equipped with a means for introducing an activated or ionized modifying gas, and the source is arranged to release, reduce, or neutralize the electric charge that may accumulate on the substrate during vapor deposition. a means for merging is attached to the vapor deposition tank, and the means is provided as a layer to the outside of the substrate;
Alternatively, a vapor deposition apparatus characterized in that the vapor deposition apparatus is electrically led to or from the outside of the vapor deposition tank. 10. The device according to claim 9, wherein a conductive member is disposed in contact with or in close proximity to the substrate surface on the evaporation source side, and the electric charge is leaked through the conductive member. 11. The apparatus according to claim 9, wherein the vapor deposition tank is provided with irradiation means for irradiating the substrate with particles having a polarity opposite to the charge that can be accumulated on the substrate. 12. The apparatus according to claim 11, wherein the irradiation means comprises a thermoelectron or radiation generating device disposed within the vapor deposition tank. 13. The irradiation means includes a thermionic or radiation generating part disposed outside the vapor deposition tank, and an introduction part for guiding the generated thermionic electrons into the inside of the vapor deposition tank by penetrating the wall of the radiation M'fr vapor deposition tank. 12. A device as claimed in claim 11, comprising a monolithic structure. 14. The device according to claim 13, wherein the irradiation means is provided with means for accelerating and/or deflecting thermoelectrons or radiation by means of an electric field and/or a magnetic field. 15. The device according to claim 10, which is provided inside and/or outside of the cypress when the deposited layer has photoconductivity. 16. The apparatus according to claim 15, wherein an electrode grounded outside the vapor deposition tank is provided on the substrate surface on the evaporation source side. 17. The apparatus according to claim 15, wherein conductive substrate support means is provided in contact with the peripheral portion of the substrate surface on the evaporation source side, and this support means is grounded outside the evaporation tank. 18. An introduction pipe for introducing a modification gas consisting of at least one selected from the group consisting of hydrogen, halogen, oxygen, nitrogen, silane, phosphine, diborane, arsine, hydrocarbon and ammonia is arranged in the vapor deposition tank. 18. A device according to any one of claims 9 to 17, wherein the device is provided with: 19. The apparatus according to any one of claims 9 to 18, wherein a discharge tube is provided in the modifying gas introducing means outside the vapor deposition tank. According to any one of claims 9 to 19, the substrate is formed of an insulating material and is provided with voltage application means for applying a negative voltage to the insulating substrate. equipment.