JPS5943875A - Evaporation source and its using method - Google Patents

Abstract

PURPOSE:To prevent the internal sticking of vapor and to perform stable vapor deposition, by heating and evaporating >=2 kinds of materials to be evaporated in a vapor source with respective heat sources and controlling the temp. of the material to be evaporated which is lower in the rate of evaporation thereby controlling the temp. over the entire part. CONSTITUTION:The vessel body 10 of an evaporation source 11 is partitioned to spaces 2a, 2b by a partition wall 2 and the 1st and the 2nd Se-Te materials 3, 4 to be evaporated having respectively different concns. are stored in vessels 13, 14 and are heated and evaporated with heater lamps 5, 6. The vapors are conducted through an upper opening 7 smaller than the evaporation area thereof toward a substrate to be deposited therein with a film by evaporation (not shown). Plates 15, 16 for preventing bumping and heater lamps 17, 18 for accelerating the vapors and preventing condensation are preferably provided in the respective spaces 2a, 2b. The temp. of the 2nd material 4 which is lower in the rate of evaporation of the above-mentioned materials to be evaporated is detected with a thermocouple 19, and the lamps 5, 6 are controlled by a detection part 20 and a control circuit 21, whereby the temp. over the entire part of the source 11 is controlled constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides heating of two or more types of evaporation materials by respective heat sources.
The present invention relates to an evaporation source configured to evaporate and a method of using the same.

When manufacturing a photoreceptor made of a selenium-tellurium alloy, an evaporation source called an open boat or a Knudsen cell type is sometimes used. In the latter evaporation source, the evaporation rate is effectively controlled by narrowing the upper opening of the vessel (boat) containing the evaporation material to a narrower area than the evaporation area.
It is also excellent in that the evaporated matter ejected by bumping does not adhere to the wall and fly outward (that is, toward the substrate to be deposited) before reaching the upper opening.

As such a Knudsen cell type evaporation source, a single boat system which has a relatively simple structure and improved operability and evaporation stability has been proposed, for example, in Japanese Patent Laid-Open No. 176361/1983. As shown in FIG. 1, this known evaporation source divides the inner space of one boat 1 into two by a partition wall 2, and selenium-tellurium alloy 3.4 with different component concentrations is placed in each of these divided spaces. Each selenium-tellurium alloy is placed in the heater 5
．． 6, it can be heated and evaporated, and it can be led out from the lower part between the upper parts. In this case, the concentration profile of tellurium is controlled by individually controlling the temperature of each alloy and depositing it on, for example, a drum-shaped deposition target substrate 8 while mixing each vapor.

However, it has been found that this known device and method has drawbacks such as zero order. That is, when controlling the temperature of each evaporation material individually, for example, an alloy with a high evaporation rate (in other words, a low tellurium concentration) evaporates faster than an alloy with a low evaporation rate (in other words, a high tellurium concentration). Therefore, in the case of measuring the temperature of the former alloy with a thermocouple and controlling the temperature based on this, it is necessary to measure the temperature of the thermocouple when there is little residual alloy or when the alloy has completely evaporated. The prices are even higher than before. Based on this higher detected temperature, a control signal is then applied to the heater to reduce the heater output, resulting in a significant overall reduction in the heater output.

As a result, the temperature inside the boat becomes too low, and the steam tends to adhere to the walls, etc., making it impossible to perform stable vapor deposition. When such adhesion (internal adhesion) occurs, it causes variations in sensitivity and deterioration of fatigue characteristics of the obtained photoreceptor.

The present invention provides an evaporation source and a method for using the same, which can take advantage of the above-mentioned features of the evaporation source while correcting its deficiencies and create a deposited film with a desired concentration profile and good film quality and film properties.

That is, the present invention includes, in the evaporation source described at the beginning, a detection means for detecting the temperature of the evaporation material having a smaller evaporation rate, and a control means for controlling each of the heat sources based on the temperature detected by the detection means. It is characterized by this.

With this configuration, the evaporation source temperature during the evaporation operation can be controlled based on the temperature information of the evaporation material with a low evaporation rate, and therefore, the temperature of the evaporation source during the evaporation operation can be controlled based on the temperature information of the evaporation material whose evaporation rate is low.
That is, even if the evaporation material with a high evaporation rate has completely evaporated at this point, each heat source can always be maintained at a constant power, and the evaporation source temperature can be maintained sufficiently and constant. by this,
As mentioned above, there is no temperature drop during vapor deposition, and it is possible to prevent vapor from adhering internally and perform stable vapor deposition.
A deposited film with a desired concentration profile (good film properties such as sensitivity, film quality, and fatigue properties) can be obtained.

The evaporation source of the present invention is therefore preferably used in the following manner. That is, in a method of using an evaporation source configured to heat and evaporate two or more types of evaporation materials using each heat source, the temperature of the entire evaporation source can be adjusted by controlling the temperature of the evaporation material with a smaller evaporation rate. Each evaporation material is heated and evaporated at the same time and deposited on the substrate.

In this usage method, selenium alloys can be used for evaporation material binding, but the concentrations of the same type of component elements other than selenium are different between each selenium alloy, and selenium The types of component elements other than the above may be different from each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

The evaporation source 11 shown in FIG. 2 is constructed in the Knudsen cell type, and according to this, a partition wall 2 is provided in the container body 10 to substantially divide the internal space. In the internal spaces 2a and 2b, which are divided into spaces 2a and 2b, the first
5e-Te evaporation material 3 and second 5e-Te evaporation material 4
and are accommodated in each inner container 13, 14, respectively. A heater lamp 5.6 is arranged on each evaporation material, and furthermore, a bumping prevention plate 16 and a heater lamp 17.1B for vapor acceleration and condensation prevention are arranged on the upper part.

The first evaporation material 3 is loaded with 5e-Te, which has a high evaporation rate, for example, a Te concentration of 4 weight, and the second evaporation material 4 has a low evaporation rate, for example, with a Te concentration of 2. The configuration that should be used is 5, which has a low evaporation rate.
Temperature information measured by a thermocouple 19 inserted into the eTed is input to a control circuit section 21 via a detection section 20, and the power of each heater 6 and 5 is controlled by this control circuit section. . Therefore, in order to achieve the above-mentioned effects of the present invention, the evaporation source temperature can always be kept constant based on the temperature of the material 4 with a low evaporation rate, and during this time, the temperature of the material 3 with a high evaporation rate (i.e., the inner space 2a) can be kept constant. The temperature will also be kept high. The thermocouple 22 inserted into the material 3 is used merely for temperature measurement.

FIG. 3 shows the temperature control program described above. Heaters 5 and 6 are turned on at the same time to raise each evaporation material to a predetermined evaporation temperature T (for example, 290°C), and then the temperature is maintained at this temperature. The vapor deposition operation is performed by holding the temperature for a predetermined time. During this time, 5e-Tea, which is easily evaporated, evaporates, and even if all of this evaporates, Se-Te4 still evaporates. In this case, even if 5e-Te3 disappears at time tl and the temperature rises to a much higher temperature (for example, 330°C) as shown by the broken line, this temperature is ignored and the temperature of 5e-Te4 (i.e., constant evaporation The temperature is controlled so that the temperature is maintained, and the nozzles of heaters 5 and 6 are maintained. As a result, the temperature of the evaporation source as a whole is always kept constant, so problems such as internal adhesion as described above do not occur.

On the other hand, when the heater is controlled based on the temperature of 5e-Tea, which has a high evaporation rate, as shown in Figure 4, the power of the heater is adjusted according to the temperature increase shown by the broken line in Figure 3. Since the temperature of the evaporation source is controlled to decrease, the actual temperature of the evaporation source drops from the time point t, as shown by the solid line, resulting in an inappropriate state.

The degree of vacuum in the vapor deposition tank during vapor deposition is 10-”T.
It is preferable to set it to Orr or more.

As a result of analyzing the deposited film obtained according to the present invention, that is, the 5e-Te photoreceptor, with an X-ray microanalyzer, it showed an ideal Te concentration profile as shown in FIG. The surface layer is composed of 18% by weight of Te and functions as a charge generation layer with particularly good sensitivity at long wavelengths due to the high tellurium content. Regarding this photoreceptor, electrophotographic copying machine U
-BixV (manufactured by Konishiroku Photo Industry Co., Ltd.) was examined for actual photographic characteristics, and high-density images without capri were obtained.

As described above, according to the evaporation source and method of using the same according to the present invention, the structure of the evaporation source itself is simplified, and desired concentration control can be easily performed. The density profile obtained (see Figure 5) is very desirable, and it shows excellent electrostatic properties such as high sensitivity of the photoreceptor, potential retention, low residual potential, and low black paper potential. It becomes something that can be performed.

Note that the chill concentration between the above-mentioned evaporation materials 3 and 4 can be variously selected; for example, in the first evaporation material 3, Te1l
¥! The Te concentration may be selected in the range of 0 to 8% by weight, and the Te concentration in the second evaporation charge 4 may be selected in the range of 15 to 25% by weight.

Further, other component elements such as arsenic, antimony, etc. may be used in place of tellurium, and these may be the same type for each evaporation material, or the types may be different. Figure 6 shows another example. Although the evaporation source is shown here, there is no partition wall between each evaporation material 3.4 as described above, and each evaporation material is arranged in a common inner space 12, and a common bumping prevention plate 15 is provided. , a heater 17 is provided. Note that the temperature detection and control circuit system described above is not shown.

Even in such an evaporation source, if the heaters 5, 6 are individually controlled, internal adhesion as described above tends to occur.

Therefore, it is effective to control the temperature as shown in FIG. 2 according to the present invention.

According to the evaporation source shown in Fig. 6, since there is no partition wall, each evaporation material can be evaporated into a common space, so that the mixture of vapors is made uniform, and a continuous concentration control is achieved by uniformity. can be done. In addition to this, another advantage of not providing a partition wall in the container is that it is possible to avoid corrosion of the partition wall (due to tellurium) and contamination of the deposited film with impurities, which would occur if a partition wall was provided.

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, the shape and structure of the evaporation source, and the arrangement and number of evaporation materials can be changed in various ways. In addition, the evaporation material used is 5e-Te.
Se-S, , Fe-Ni, AyBr I
etc. may be used. The present invention is also applicable to open boat type evaporation sources.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of main parts of a conventional vacuum evaporation apparatus. Figures 2 to 6 show examples of the present invention, in which Figure 2 is a cross-sectional view of the evaporation source, Figure 3 is a temperature program diagram of the evaporation source, and Figure 4 is a conventional evaporation source. Temperature program diagram, 5th
The figure shows the tellurium concentration profile of the deposited film, and FIG. 6 is a cross-sectional view of another evaporation source. In addition, in the reference numerals shown in the drawings, 2---------1 partition 3-------- Evaporation material 4 with low tellurium concentration
Evaporation material with high tellurium concentration 5.6.17.1B------
Sweater - 7 - - Soil opening 8 - - Vapor deposition substrate 11 - Evaporation source 15.16 - Bumping prevention plate 19.22 - - Thermocouple 20 --- Temperature detection section 21 --- Control circuit section. Agent Patent Attorney Hiroshi Aisaka Figure 3 Figure 4 Time Figure 5 Figure 6 3 4

Claims (1)

[Scope of Claims] 1. In an evaporation source configured to heat and evaporate two or more types of evaporation materials using respective heat sources, a detection means for detecting the temperature of the evaporation material with a smaller evaporation rate, and this detection and control means for controlling each of the heat sources based on the temperature detected by the means. 2. The evaporation source according to claim 1, wherein the temperature information detected by the temperature detection means is transmitted to a control circuit connected to each heat source. 3. The evaporation source according to claim 1 or 2, wherein the temperature detection means is a thermocouple. 4. The evaporation source according to claims 1 to 3, wherein each evaporation material is led out through an opening smaller than its evaporation area. 5. According to claim 4, each evaporative material is housed in a single container, and a partition wall is provided between each evaporative material to substantially divide the internal space of the container. source of evaporation. 6. According to claim 4, wherein each evaporative material is housed in a single container, and there is no partition between each evaporable material that substantially divides the internal space of the container. source of evaporation. 7. Heaters are arranged to heat each evaporation material, and these heaters are configured to be turned on at the same time.
An evaporation source according to any one of claims 1 to 6. 8. The evaporation source according to any one of claims 1 to 7, wherein a bumping prevention plate is provided on the evaporation material. 9. In a method of using an evaporation source configured to heat and evaporate two or more evaporation materials using each heat source, the temperature of the entire evaporation source is controlled by controlling the temperature of the evaporation material with a smaller evaporation rate. . A method of using an evaporation source, characterized in that each evaporation material is simultaneously heated and evaporated and deposited on a substrate to be evaporated. 10. Detecting the temperature of the evaporation material with the smaller evaporation rate,
10. The method according to claim 9, wherein this temperature information is input to a control circuit section, and the control circuit section controls each heat source for each evaporation material. 11. Claim 9 or 1, in which each evaporation material is led out through an opening smaller than its evaporation area.
The method described in item 0. 12. Each evaporation material is housed in a single container, and a partition wall is provided between each evaporation material to substantially divide the internal space of the container, according to claims 9 to 11. The method described in any one of the paragraphs. 13. Claims 9 to 11, wherein each evaporative material is housed in a single container, and no partition wall is provided between each evaporative material to substantially divide the internal space of the container. The method described in any one of the paragraphs. 14. The method according to any one of claims 9 to 13, wherein heaters are provided to heat each evaporation material, and these heaters are turned on at the same time. 15. The method described in any one of claims 9 to 14, wherein a selenium alloy is used as the evaporation material. 16. The method according to claim 15, wherein the concentrations of constituent elements of the same -m class other than selenium are different among the selenium alloys. 17. The fifteenth aspect of claim 1, wherein the types of constituent elements other than selenium are different between the selenium alloys.
The method described in section.