JP3206760B2 - K cell for vacuum evaporation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The k-cell for vacuum deposition of the present invention is used for heating or evaporating or sublimating a chemical substance in a vacuum in a chemical substance deposition operation.

[0002]

2. Description of the Related Art Various kinds of k-cells have been proposed for heating and evaporating or sublimating chemical substances in a chemical substance deposition operation. FIG. 1 shows a typical structure. Conventional k
Since the cell is designed to deposit inorganic compounds at a high temperature of 600 ° C. or higher, the crucible contains alumina or PB.
N is used. In addition, a wire heater made of tantalum or the like is used for the heater to have a structure suitable for high-temperature use. In this kind of k-cell, the winding resistance and the winding interval of the heater are designed to improve the temperature controllability at the time of high temperature use. Inferior in temperature controllability. For this reason, there is a drawback that it is not suitable for the vapor deposition operation of a chemical substance having a low boiling point and low sublimation point. Further, when used at a low temperature, there is a disadvantage that a temperature gradient corresponding to the heater winding interval or a temperature gradient due to uneven winding of the heater is easily generated.

[0003] With the progress of research and development of organic nonlinear optical materials in recent years, there have been more opportunities to deposit organic compounds to form thin films. Organic compounds have characteristics such as a higher vapor pressure, a lower sublimation temperature and a lower evaporation temperature than inorganic compounds. Therefore, vapor deposition is performed in a relatively low temperature range (100 to 400 ° C.). For example, vanadyl phthalocyanine (VOPc), for which a large third-order nonlinear optical constant has been reported, is one of the organic compounds that perform vapor deposition at the highest temperature [Wada, Proc. 22-29 (1989)], and the deposition temperature is about 400 ° C. For this reason, when a conventional k-cell for inorganic compounds is applied to the deposition of an organic compound, the evaporation rate is not stable due to poor temperature controllability, it is likely to be bumpy, and the evaporated material once evaporated is in a low-temperature portion near the outlet of the k-cell. Problems such as recrystallization and easy adhesion often occurred.

[0004]

If the scattering state and the remaining amount of the vapor deposition sample in the k cell can be observed during the vapor deposition, the efficiency of the vapor deposition operation can be greatly improved. Cannot be observed, the state inside the k-cell can only be estimated from a change in temperature or a degree of vacuum. If there is a transparent k-cell capable of monitoring the remaining amount of the deposition material and the adhesion state in the vicinity of the k-cell, the efficiency of the deposition operation is greatly improved.

It is an object of the present invention to solve the above-mentioned drawbacks.
It is an object of the present invention to provide a cell, that is, a k-cell for vacuum deposition in which a temperature gradient is small, controllability in a low-temperature region is excellent, and a state in the k-cell during deposition can be directly observed.

[0006]

According to the present invention, in order to achieve the above object, a k-cell for vacuum deposition is provided with a transparent crucible and a transparent crucible.
Transparent placed on or close to the side of bright pot
It was composed of a surface-type heater. Also, place the transparent crucible in the transparent
A new transparent crucible to use as a transparent support.
Configuration that is closely attached to the inside of the
Can also be.

[0007]

The temperature gradient, which has been a problem in the conventional heater winding system, is caused by uneven heating due to the interval between the windings of the heater and uneven winding. As a method of reducing the temperature gradient, it is effective to use a plane heater. Therefore, in the k-cell for vacuum evaporation of the present invention, a transparent heater made of a transparent conductive film prepared by a vacuum evaporation method, a sputtering method, a spray method, a sol-gel method, an ion plating method, an active reaction method or the like is used in combination with a transparent crucible. I do. In addition, the transparent surface type heater may be in close contact with the transparent crucible or may be made separately. When a heater and a transparent crucible are separately manufactured, the transparent crucible is inserted into a transparent heater support. When the transparent conductive film formed on the side surface of the crucible is used as a heater, since the heater is a planar heater, the deposition material in the k cell is uniformly heated, and the temperature gradient can be reduced.
Further, when the heater resistance value is adjusted in order to obtain a k-cell having good controllability in a low-temperature region, it can be easily dealt with by increasing or decreasing the thickness of the surface heater. Furthermore, the k of the present invention
Cells, Ru for pot and the heater are both transparent material has the advantage that it is possible to observe the state of the k cell during deposition directly. Examples of the material of the transparent conductive film used in the present invention include indium oxide (In ₂ O ₃ ), indium oxide (ITO) doped with tin (Sn), indium oxide doped with fluorine, and tin oxide (Sn oxide).
O _2), fluorine-doped tin oxide (SnO _2), antimony (Sb) doped tin oxide (SnO _2),
CdSnO ₄ (CTO) and the like. As the material of the transparent k-cell crucible, in addition to optical glass materials such as flint glass and crown glass, quartz, sapphire,
Hard glass, calcium fluoride, or the like can be used. Although it is possible to increase the resistance value by patterning a transparent heater spirally necessary, the temperature controllability for no longer planar heaters of course decrease.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 2 is a partial vertical cross-sectional view of a vapor deposition k-cell of the present invention. The transparent crucible 9 is made of quartz and has an internal capacity of 10 cc. The transparent surface type heater 10 was produced by depositing ITO on the outer wall surface of the transparent crucible 9 by a sputtering method. Transparent surface heater 10
One electrode 11 and 12 are provided at the upper end and the lower end, respectively, and one lead wire 13 and 14 is taken out from the electrode. FIG.
1 g of copper phthalocyanine was filled in the k-cell shown in FIG.
Placed under ^-9 torr vacuum. Copper phthalocyanine (CuPc) by passing a current between two electrodes of a transparent surface heater
The temperature of the k-cell when was evaporated was measured using a thermocouple 8. Further, the film thickness of CuPc adhered to a 25 ° C. quartz film thickness meter installed at a position 20 cm from the tip of the k-cell was also measured. FIG. 3 shows the change over time of both measured values.
The temperature of the k cell is gradually increased by 270, 290, 310, and 33.
When the temperature is set to 0 ° C., the k-cell temperature reaches a stable state in about 10 minutes for a set temperature increase of 20 ° C. or more at 270 ° C. or more. After reaching the set value, the temperature change falls within the range of ± 0.05 ° C. The film thickness also increases at a constant rate after reaching the set temperature, which indicates that the deposition material is heated uniformly. Furthermore, the k-cell maintained a transparent state even during heating, and the experiment could be performed while directly observing the internal state such as the remaining amount of CuPc. On the other hand, in a similar test result (FIG. 4) performed using a conventional wound heater type k cell, the time until the temperature reaches the set temperature and stabilizes is as long as about 25 minutes, and thereafter, ± 0. A temperature fluctuation of about 3 ° C. is shown. Further, even when the set temperature was kept constant, the increase in the thickness of the vapor-deposited film gradually decreased, so that it was presumed that there was a temperature gradient in the k-cell and the vapor-deposition rate changed over time. . As described above, a k-cell using an ITO film deposited on a quartz transparent crucible by a sputtering method as a transparent surface type heater has a small temperature gradient and excellent controllability in a low-temperature region around 330 ° C. Further, it was found that the state in the k cell during the vapor deposition can be directly observed.

(Example 2) In Example 1, the transparent crucible 9 of FIG.
A transparent k-cell was manufactured by changing the transparent surface type heater 10 to tin oxide (SnO ₂ ) doped with antimony (Sb). The k-cell was filled with 0.5 g of pyromellitic anhydride (PMDA) and placed under a vacuum of 10 ^-7 torr. PMDA by passing current between two electrodes of a transparent surface type heater
The temperature of the k-cell when was evaporated was measured with a thermocouple. Further, the thickness of PMDA attached to a quartz film thickness meter at 25 ° C., which was set at a position 20 cm from the tip of the k cell, was also measured. FIG. 5 shows the change over time of both measured values. k
When the cell temperature is set to 75, 80, 85, 90 ° C. stepwise, the k-cell temperature reaches a stable state in about 5 minutes for each set temperature increase of 5 ° C. above 75 ° C. I have. After reaching the set value, the temperature change falls within the range of ± 0.05 ° C. The film thickness also increases at a constant rate after reaching the set temperature, which indicates that the deposition material is heated uniformly. Further, the k-cell maintained a transparent state even during heating, and the experiment could be performed while directly observing the internal state such as the residual amount of PMDA. On the other hand, in a similar test result performed using a conventional wound heater type k cell, it is difficult to keep the variation of the indicated temperature of the thermocouple with respect to the set temperature within ± 2 ° C. in the temperature range of the present test. Met. Furthermore, since the time change of the deposition rate was rapid, it was presumed that the temperature gradient in the k cell was large. It should be noted that the conventional k cell could not control the deposition rate in the temperature range of this experiment. As described above, the antimony-doped tin oxide film fabricated on the transparent sapphire crucible was
It was found that the k-cell used as the surface heater had excellent controllability in a low-temperature region around 75 ° C., and that the state in the k-cell during vapor deposition could be directly observed.

(Embodiment 3) FIG. 6 is a partial vertical sectional view of a k-cell for vapor deposition of the present invention. The difference in structure from the first and second embodiments is the same as FIG.
In this embodiment, the transparent crucible 9 is used as the transparent heater support 15, and a transparent crucible 16 made of quartz is newly inserted in close contact with the inside of the transparent heater support 15.
That is, from the inside, the transparent crucible 16 and the transparent heater support
15, the transparent surface type heaters 10 are sequentially arranged in close contact with each other.
I have. Accordingly, when changing the evaporation material, only the transparent crucible 16 needs to be replaced, and the workability is improved as compared with the first embodiment. In this embodiment, hard glass was used as the transparent heater support 15, and tin oxide doped with antimony was vacuum-deposited on the side surfaces thereof and then fired at 500 ° C. to form the transparent surface heater 10. Transparent crucible 16
Is made of quartz and has an internal capacity of 10 cc. FIG. 5 shows the characteristic diagram of the k-cell in tetramethyltetraselenafulvalene (T
MTSF) and placed under vacuum at 10 ^-8 torr. The temperature of the k-cell when TMTSF was evaporated by passing a current between the two electrodes of the transparent heater was measured using a thermocouple 8. In addition, TMT attached to a quartz film thickness meter at 25 ° C. installed at a position 20 cm from the tip of the k-cell.
The film thickness of SF was also measured. FIG. 7 shows the change over time of both measured values. The temperature of the k cell is gradually increased by 215, 225,
When the temperature is set to 235 ° C and 245 ° C, the temperature of the k-cell reaches a stable state in about 10 minutes for each set temperature increase of 215 ° C or more at 10 ° C. After reaching the set value, the temperature change falls within the range of ± 0.05 ° C. The film thickness also increases at a constant rate after reaching the set temperature, which indicates that the deposition material is heated uniformly. Further, the k-cell maintained a transparent state even during heating, and the experiment could be performed while directly observing the internal state such as the remaining amount of TMTSF. On the other hand, in a similar test result performed using a conventional wound heater type k cell, as in the case of the conventional cell in Example 1, the time required to reach the set temperature and stabilize was about 25%. Minutes, and the temperature fluctuates by about ± 0.3 ° C. after that. Furthermore, even when the set temperature was kept constant, the increase in the thickness of the deposited film gradually decreased, so that it was inferred that there was a temperature gradient in the k cell and the deposition rate changed over time. . As described above, the k-cell having the structure shown in FIG. 6 has a small temperature gradient and excellent controllability in a low-temperature region around 230 ° C.
Further, it was found that the state in the k-cell during the vapor deposition can be directly observed.

[0012]

As described in detail above, the k of the present invention
When an organic compound is deposited using a cell, the temperature gradient in the k cell is small and the temperature controllability in a low temperature range of 75 to 330 ° C. is good, so that the deposition rate can be kept constant. Further, since the inside of the k cell can be observed during the vapor deposition, the vapor deposition operation can be performed while checking the scattering state and the residual amount of the vapor deposition sample. Therefore, it is clear that an abnormality can be found earlier than in the conventional method in which the state inside the k-cell can only be inferred from changes in the temperature and the degree of vacuum of the k-cell.
Further, there is an advantage that the time for adding a sample can be appropriately determined.

[Brief description of the drawings]

FIG. 1 shows a structural diagram of a conventional wound heater type k cell.

FIG. 2 is a partial longitudinal sectional view of a k-cell for vapor deposition according to one embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a time change of a temperature of a k-cell and a deposition film thickness according to the present invention.

FIG. 4 is a characteristic diagram showing a temporal change of a temperature and a deposition film thickness of a conventional k cell.

FIG. 5 is a characteristic diagram showing a time change of a temperature of a k-cell and a deposition film thickness according to the present invention.

FIG. 6 is a partial vertical sectional view of a k-cell for vapor deposition according to another embodiment of the present invention.

FIG. 7 is a characteristic diagram showing a time change of the temperature of the k-cell and the thickness of the deposited film in the characteristic diagram of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Crucible 2 Lid 3 Heater wire 4 Supporter 5, 9 Insulator 6 Metal lid 7 Holder 8 Thermocouple 9 Transparent crucible 10 Transparent surface heater 11 Upper electrode 12 Lower electrode 13, 14 Electrode lead wire 15 Transparent heater support 16 Transparent crucible

──────────────────────────────────────────────────続 き Continuation of the front page (72) Takayoshi Hayashi Inventor Nippon Telegraph and Telephone Corporation, 1-6-1 Uchisaiwaicho, Chiyoda-ku, Tokyo (56) References JP-A-4-160147 (JP, A) JP-A-Hei 4-372933 (JP, A) Japanese Utility Model 2-10456 (JP, U) Japanese Utility Model 4-40762 (JP, U) Japanese Utility Model 4-53051 (JP, U) Japanese Utility Model 4-44360 (JP, U) U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58

Claims (4)

(57) [Claims] 1. A transparent crucible and translucent brightness k cells for vacuum vapor deposition and a transparent surface type heater that is installed close to the side surface or on the side surface of the pot. 2. A transparent crucible and an outer wall of the transparent crucible.
A transparent heater support to be attached,
With a transparent heater installed along the outer wall
K cell for vacuum evaporation. Wherein the transparent surface type heater, k cells for vacuum deposition according to claim 1 or 2, characterized in that a transparent conductive film composed mainly of indium oxide or tin oxide. 4. The transparent surface type heater is a transparent conductive film containing indium oxide or tin oxide as a main component, and the transparent crucible is made of quartz, hard glass, or sapphire. 3. The k-cell for vacuum deposition according to 1 or 2 .