JPH0260754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, two or more types of evaporation materials are arranged so as to be heated and evaporated by a heat source, and by operating the heat source, even if one of the evaporation materials is completely evaporated. The present invention relates to an evaporation source configured such that the other evaporation material is further evaporated, and a method for using the same.

When manufacturing a photoreceptor made of a selenium-tellurium alloy, an evaporation source called an open boat or a Knut-Sensel type is sometimes used.
In the latter evaporation source, the evaporation rate is effectively controlled by constricting the top opening of the vessel (boat) containing the evaporation material to be narrower than the evaporation area, and the evaporation rate is effectively controlled until the evaporation material that flies out due to bumping reaches the top opening. It is excellent in that it does not adhere to the wall during the process and will not fly outward (that is, toward the substrate to be evaporated).

These Knutsensell type evaporation sources are
A single boat system with a relatively simple configuration and improved operability and evaporation stability is proposed, for example, in JP-A-55-
Proposed in No. 176361. 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 in each of these divided spaces, selenium-tellurium alloys 3, 4 with mutually different component concentrations are placed.
The heater 5,
6, it can be heated and evaporated, and it can be led out from the upper opening 7. In this case, the tellurium concentration profile is controlled by individually controlling the temperature of each alloy and depositing it on, for example, a drum-shaped substrate 8 while mixing each vapor.

However, it has been found that this known device and method has the following drawbacks. 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, the temperature value measured by the thermocouple will be will be 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 drops too much, making it easy for steam to adhere to the walls and the like, 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 properties. .

That is, in the evaporation source mentioned at the beginning of the present invention,
The present invention is characterized by having a detection means for detecting the temperature of the evaporation material that is evaporated to the end, and a control means for controlling the heating source based on the temperature detected by the detection means.

With this configuration, the evaporation source temperature during the evaporation operation can be controlled based on the temperature information of the evaporation material whose evaporation rate is low. Even if all of the evaporation material with a large amount has been evaporated), each heat source can always be maintained at a constant power, and the evaporation source temperature can be maintained sufficiently and constant. As a result, 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, and to achieve the desired concentration profile (film characteristics such as sensitivity, film quality, etc.). A deposited film with good fatigue properties can be obtained.

The evaporation source of the present invention is therefore preferably used in the following manner. That is, by arranging two or more evaporation materials to be heated and evaporated by a heat source and activating the heat source, even if one evaporation material is completely evaporated, the other evaporation material is further evaporated. In the method of using the evaporation source configured as above, the temperature of the entire evaporation source is controlled by detecting the temperature of the evaporation material that is evaporated to the end, and each evaporation material is simultaneously heated and evaporated to be deposited on the substrate to be evaporated. do.

In this usage method, a selenium alloy can be used as the evaporation material, but the concentrations of the same type of component elements other than selenium may differ between each selenium alloy, and The types of component elements 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 a Knutsensel type, and according to this, there is a partition wall 2 inside the container body 10 that substantially divides the internal space.
The internal spaces 2a and 2 separated by this
In b, the first Se-Te evaporation material 3 with different concentrations
and the second Se-Te evaporation material 4 in each inner container 13,
They are housed in 14. Heater lamps 5 and 6 are disposed on each evaporation material, and bumping prevention plates 15 and 16 and heater lamps 17 and 18 for vapor acceleration and condensation prevention are further disposed on the top.

As the first evaporation material 3, Se-Te with a high evaporation rate, for example, a Te concentration of 4% by weight, is loaded, and as the second evaporation material 4, Se-Te with a low evaporation rate, for example, a Te concentration of 20% by weight, is loaded. Loaded separately.
The noteworthy configuration here is that the temperature information measured by the thermocouple 19 inserted into the Se-Te 4 having a low evaporation rate is input to the control circuit section 21 via the detection section 20. The power of each heater 6 and 5 is controlled by.
Therefore, in order to achieve the above-described 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)
The temperature will also be maintained high. The thermocouple 22 inserted into the material 3 is used merely for temperature measurement.

FIG. 3 shows the above temperature control program, in which heaters 5 and 6 are turned on at the same time, and each evaporation material is heated to a predetermined evaporation temperature T (for example, 290°C).
℃) and held at this temperature for a predetermined period of time to perform the vapor deposition operation. During this time, Se-
Te3 evaporates, and even if all of this evaporates, it continues
Se-Te4 still evaporates. In this case, Se−Te3
Even if the temperature disappears at time t ₁ and the temperature rises to a higher temperature (for example, 330℃) as shown by the broken line, this temperature is ignored and the temperature of Se-Te4 (i.e., constant evaporation temperature) is
The temperature is controlled to maintain the power of the heaters 5 and 6. 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 Se-Te3, 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 _t1 as shown by the solid line, resulting in an inappropriate state. Note that the degree of vacuum in the vapor deposition tank during vapor deposition is preferably 10 ⁻³ Torr or higher.

The deposited film obtained according to the present invention, namely Se-Te
As a result of analyzing the photosensitive layer with an X-ray microanalyzer, it showed an ideal Te concentration profile as shown in Figure 5, with the inner layer containing 5% by weight of Te and functioning as a charge transport layer, and the surface layer containing 18% by weight of Te. , functions as a charge generation layer with particularly good sensitivity in the long wavelength range due to the high tellurium content. In addition, when we investigated the photosensitive characteristics of this photoreceptor using an electrophotographic copying machine U-BixV ₂ (manufactured by Konishiroku Photo Industry Co., Ltd.), we found that
A high-density image with no fog was 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 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 played.

Note that the tellurium concentration between the above-mentioned evaporation materials 3 and 4 can be selected variously. For example, the first evaporation material 3 has a Te concentration of 0 to 8% by weight, and the second evaporation material 4 has a Te concentration of 15 to 25% by weight. You may select each within the range of %. In addition, other component elements can be used instead of tellurium.
For example, arsenic, antimony, etc. may be used, and these evaporation materials may be of the same type or may be of different types.

FIG. 6 shows another example of an evaporation source, in which no partition wall as described above is provided between the evaporation materials 3 and 4, and each evaporation material is arranged in a common inner space 12. , a common bumping prevention plate 15 and a heater 17 are provided. Note that the temperature detection and control circuit system described above is not shown.

Even in such an evaporation source, the heaters 5 and 6
If these 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.

In addition, 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 can be made uniform, and the concentration can be controlled uniformly or continuously. . 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 materials used are not limited to Se-Te, but also Se-S, Fe-Ni, AgBr
-I etc. may be used. The present invention is also applicable to open boat type evaporation sources.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of main parts of a conventional vacuum evaporation apparatus. 2 to 6 show embodiments of the present invention, in which FIG. 2 is a cross-sectional view of the evaporation source, and FIG.
Figure 4 is a temperature program diagram of an evaporation source, Figure 4 is a temperature program diagram of a conventional evaporation source, Figure 5 is a diagram showing the tellurium concentration profile of a deposited film, and Figure 6 is a cross-sectional view of another evaporation source. be. In addition, in the symbols shown in the drawings, 2... partition wall, 3... evaporation material with low tellurium concentration, 4... evaporation material with high tellurium concentration, 5, 6, 17, 18... heater, 7... upper part Opening, 8... Vapor deposition target substrate, 1
1... Evaporation source, 15, 16... Bumping prevention plate, 1
9, 22...Thermocouple, 20...Temperature detection section, 21
...This is the control circuit section.

Claims (1)

[Claims] 1. Heating two or more evaporation materials with a heat source,
The evaporation source is arranged so that the evaporation material is evaporated to the end, and the heating source is operated so that even if one evaporation material is completely evaporated, the other evaporation material is further evaporated. An evaporation source comprising: a detection means for detecting temperature; and a control means for controlling a heating source based on the temperature detected by the detection means. 2 Heating two or more evaporation materials with a heat source,
In a method of using an evaporation source configured to evaporate and operate a heating source, even if one evaporation material is completely evaporated, the other evaporation material is further evaporated. A method of using an evaporation source, characterized in that the temperature of the entire evaporation source is controlled by detecting the temperature of the evaporation material, and each evaporation material is simultaneously heated and evaporated to be deposited on a substrate to be evaporated.