JPS609870A - Method for manufacturing tellurium low oxide thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a manufacturing method for forming a tellurium low oxide thin film as an optical information recording medium with good reproducibility.

Structure and problems of conventional examples Tellurium low oxide thin film TeOx (○<X<2) is known as an optical information recording thin film with high sensitivity and high signal quality (Japanese Patent Publication No. 54-3725), and it has already been developed. Still image files, document files, etc. have been commercialized using this technology.

Conventionally, the following methods have been known as means for forming a TeOx (◯<X<2) thin film.

(1) Tungsten boat or molybdenum boat 5
A method in which TeO2 powder is placed on a sheet and vacuum evaporated.

In this method, a tungsten boat or a molybdenum boat is energized and heated to cause a reduction reaction with TeO2 on the boat surface, and evaporates while removing some of the oxygen in TeO2 to form TeOx (o < X < 2). The aim is to obtain. This method is extremely easy to use with TeO
It has the advantage of being able to obtain 2, but on the other hand.

As the reaction progresses, the reducing power of the boat surface decreases, causing a deviation in the Te and 00 composition ratios in the film thickness direction. Also, since it is necessary to replace the boat every time, the reaction speed is limited.
The problem was that reproducibility was difficult.

(2) A method of synthesizing TeOx (0<X<2) by preparing two sources of Te and TeO2, controlling the deposition temperature from each source, and simultaneously depositing them on a substrate.

This method can obtain a TeOx thin film with an arbitrary composition ratio by controlling the vapor deposition temperature of the valley source.

This method has many advantages, such as being able to perform vapor deposition many times in succession (Proceedings of the 28th Applied Physics Conference, P108 (1981)).

6・′ However, this is because Te is a substance with extremely high vapor pressure.

It is very difficult to control the deposition rate, and there are problems in that dropouts occur due to bumping and the reproducibility of characteristics is insufficient.

(3) A method of mixing TeO2 with a metal as a reducing substance and vapor-depositing it in a quartz crucible while causing a reduction reaction using a coil heater or the like (Proceedings of the 28th Applied Physics Conference Proceedings P108 (1981)).

In this method, TeO2 powder and reduced metal powder are mixed in advance and heated in a quartz crucible.
This method involves vapor deposition while reducing eO2, but in this method, the reducing power of the reducing metal decreases as the reaction progresses, resulting in a large compositional deviation in the film thickness direction.Conversely, the reaction progresses rapidly in the initial stage. There were technical problems such as sauce spilling.

Object of the Invention The present invention relates to each of the above methods. The present invention provides a method for producing a tellurium low oxide thin film as an optical information recording material, which solves problems such as reproducibility, controllability, and uniformity, and which is easy, efficient, and has excellent reproducibility.

Structure of the Invention In order to achieve the above object, the present invention is characterized in that a sintered body obtained through the steps described below is used as a vapor deposition source.

a) Step of mixing TeO2 and reducing substance, b
) A step of heat-treating the mixture to cause a portion of TeO2 to react with a reducing substance.

According to the present invention, most of the reduced form of TeO2 produced by heat treatment combines with a part of the reduced metal to form the compound Te-
M is formed, unreacted TeO2, and oxidized t'L fc MO as a result of the reaction - to form a uniform sintered body. During vapor deposition, TeO2 in this sintered body and
The Te released from the Te-M bond is simultaneously vapor-deposited to form TeOx (0<x<2) on the substrate, but in the method using this sintered body, the sintered body is vapor-deposited while being reduced. Compared to the method, there is no rapid reaction, so there is no phenomenon of the source spreading over and over, and since the dissociation of Te progresses gradually at a constant speed, there is little deviation in the composition in the film thickness direction. By preparing a large amount of source at one time and then fractionating it for use, films with the same characteristics can be obtained with much better reproducibility than other methods. In addition, results were observed when a membrane resistant to humidity was obtained.

DESCRIPTION OF EMBODIMENTS FIGS. 1 to 3 show examples of steps for making a sintered body according to the present invention.

1 is a cross section of the mortar. TeO2 powder 3 and reducing substance 4 are placed in this and mixed well in mortar 2.

A ball mill can also be used for mixing.

Further, by adding and mixing alcohol, acetone, etc., it becomes easier to make the mixture uniform. After the mixed powder 5 is dried, it is placed on a quartz boat 6 as shown in FIG. 2, and heat-treated in an electric furnace as shown in FIG. 3. In Figure 3, 7 is a quartz furnace tube, 8 is a heater, 9 is a heat insulator, 10 is an outer wall, 1
1 indicates a thermocouple. During heat treatment, use N2. This is carried out in an inert gas atmosphere such as Ar. 12 is a gas inlet, and 13 is a gas outlet. Although the heat treatment temperature varied depending on the reducing substance, a sufficient reaction occurred between approximately 40° C. and 1 Q00° C., and a hard sintered body could be obtained. If the heat treatment temperature is below 4°C, the reaction will not proceed sufficiently, and the
If the temperature is higher than 0.degree. C., the Te component may be deposited during the treatment, which is not suitable.

Reducing substances include Al, Si, Ti, V,
Cd, In.

Sn, Sb, Ta, W, Or, Mn, Fe
, Go+Ni, (u, Zn.

Metals or metalloids such as Ge, Mo, Bi, Pb, or S.

Ss, C, etc. can be used. The above reducing substance is
Reacts with TeO2 by heat treatment, e.g. mTeO2+
nM −+ TeM + MO + TeO2. Namely.

Part of TeO2 is reduced by part of the reducing substance M to become Te, and at the same time, M takes away 0 and becomes MO.

It becomes oxides in the form of M2O3 and MO2. At this time,
Most of f(Te3 produced by reduction is left unreacted and combines with frM to form M2Te, MTe, M2
It takes the form of Te3, MTe2, etc., and is contained in the sintered body. Therefore, the sintered body obtained as a result of heat treatment has M
-Te alloy.

It can be said that it is an aggregate of M-0 oxide, TeO2.

10' Among the aforementioned reducing substances, Cu, Sb, Pb, A
l, In.

Zn, Bi, Ge, Se, Cd are
In addition to reducing tellurium dioxide at a moderate rate, it is possible to obtain a uniform sintered body with good compatibility with Te produced by the reduction.7 In particular, Cu, Al, Sb,
It was found that the elements Pb and In have very high compatibility with Te, and an extremely uniform sintered body can be obtained.

The appropriate mixing ratio of the reducing agent was 15 m01% to 80 m01%. If the mixing ratio is less than 15nlO1, the reduction will not proceed sufficiently, and the low tellurium oxide thin film deposited using this sintered body will have a very high O component, as will be described later, and the light absorption coefficient will be small. The front and rear optical changes were insufficient. ′! If the mixing ratio is 80 parts or more, the reduction will proceed too much, and the tellurium low oxide thin film deposited using this sintered body will be a film with a very high Te content and will have thermally unstable characteristics. Therefore, it could not be used as an optical information recording film. When the mixing ratio is between 15% and 80%, a sintered body with moderate reduction of TeO2 is obtained. It was found that a low oxide thin film could be obtained.

FIG. 4 shows a method of forming a low tellurium oxide thin film using the sintered body obtained as described above. The vacuum degree of the vacuum system 12 may be about 10 Torr to 71 (+Torr), but not more than 10 Torr.

A strong film with high adhesion can be obtained. For example, the sintered body 19 is placed in a quartz container 17, heated from the outside with a coil heater 16, and placed on the support base 14.
A tellurium low oxide thin film is deposited thereon. The appropriate heater temperature is 500°C to 1000°C, and the deposition rate and film composition can be controlled within this range. The coil heater is connected to an external power source 18 via an electrode 15,
It has a mechanism that heats it with electricity.

By producing the sintered body source in large quantities, pulverizing it, and then fractionating it for use, it becomes homogeneous and can further improve reproducibility.

As a heating method, in addition to the method of heating the whole from the outside with a heater as described above, there is a method of rapidly heating locally using an electron beam. In this case, it is easier to heat the source by using a pellet-like material 20 made of solidified sintered material as shown in FIG. 5 as the source. This pellet is formed using a jig 21 as shown in FIG. The jig is the presser rod portion 21a.

It consists of a main body 21b and a bottom part 2IC. Powder 22 obtained by crushing the sintered body is placed in this and pressed to compact and shape the powder. Compared to the case of using a heater, the method using an electron beam makes it possible to (a) raise the temperature of the pellet rapidly and locally, and there is less compositional deviation than when heating the entire pellet with a heater; Become. (b) In addition to the advantage that the vapor deposition rate can be easily controlled due to the fast response, (c) it was found that the moisture resistance was further improved as will be described later. Membranes made using a method using sintered bodies have a denser structure than membranes made using other methods, and are therefore thought to be less susceptible to the effects of outside air.
Thin films formed by electron beams have a more dense and homogeneous film structure, and are hardly affected by outside air, so it is thought that humidity deterioration is small.

Next, the present invention will be explained using more specific examples. do.

Example 1 Using TeO2 powder and Cu powder as starting materials, T
111.72 g (about 0.7 mol) of e02,
19.68 g (approximately 0.3 mol) of Cu is mixed with a small amount of alcohol in the manner shown in FIG. 10 og of the mixed powder was placed on a quartz boat and heat treated using the electric furnace shown in FIG. Put the sample into the furnace tube and 21/
While flowing N2 gas at H8 degrees, raise the temperature of the furnace to about 3
The temperature was raised to 700'C for 0 minutes, and after holding the i dimension for about 2 hours, the sample was taken out to the low-temperature part of the furnace and cooled. After about 1 hour, when taken out of the furnace, a black-brown glassy solid was obtained. It was done.

This solid material was taken out from the quartz boat, and a portion thereof was used for vapor deposition using the system shown in FIG.

With a vacuum level of 1 x 10 Torr and a motor temperature of 7°C, approximately 200 small pieces of the same size of the solid material were placed in a quartz container and heated (-), and the film thickness was approximately 1200 mm, with a slight yellowish tinge. A transparent brown TeOx thin film was formed on the acrylic resin substrate.24 semiconductor laser beams of λ14-' =90 onm were focused on this thin film using the optical system shown in Figure 7, and irradiated. It was confirmed that the part of the body undergoes a blackening metamorphosis.

Example 2 In Example 1, the mixing ratio of Cu was ○~100 mo1%
As a result of conducting a similar experiment by changing the mixing ratio between 0 and
A uniform black-brown sintered body was obtained over the range of g □ mo1%. As a result of vapor deposition using this sintered body in the same manner as in Example 1, a film with a very low optical density was obtained when the mixing ratio was between Q and 15 mo1%, and a large change in concentration was obtained even when irradiated with semiconductor laser light. There wasn't. In addition, when the mixing ratio becomes 1% or more, the optical density increases, but the film is unstable, and the vapor deposited material is a dark brown transparent film, but it changes rapidly at room temperature and becomes opaque. It turned out to be a slightly metallic black film. Mixing ratio is 15-8
Between 0m01%, a stable yellowish-brown transparent film was obtained, which was transformed into black by semiconductor laser light.

Composition analysis using Auger electron spectroscopy revealed that the film was homogeneous with almost no compositional deviation in the film thickness direction.
It was found that the value of was decreasing.

Example 3 Instead of Cu powder, Al, Si, Ti, V, C
d, In, Sn.

Sb, Ta, W, Or, Mn, Fe, Go
, Ni, Zn, (re, Mo.

Experiments similar to those in Examples 1 and 2 were conducted using the valley elements S, Se, and C, and sintered bodies were obtained in each case. In B, Sb, Pb, AI, In, Zn, Bi
, Ge.

When Ss and Cd are used, the colors are black, yellowish, and yellowish, respectively.
Black, black-brown, black, gray-brown, yellow-brown.

A glassy, homogeneous sintered body with a reddish-brown or grayish-brown color was obtained.
l, fc. Especially Al, Sb, Pb, In
When using Cu, a homogeneous glass-like sintered body could be obtained over a wide range of mixing ratios, as in the case of Cu. On the contrary, Si.

When C and Mn were used, only a slightly non-uniform sintered body was obtained.

These sintered bodies were heated in vacuum to form TeOx
(o<x<2) A thin film is obtained by nfc.

Example 4.

Next, we investigated a method of finely controlling the properties of the TeOx thin film to be obtained using a plurality of reducing substances. The reducing substances mentioned in Example 3 do not all have the same reducing ability; some are oxidized and react violently with relatively high reducing ability, such as Mo2 or M2O3, and some are
It is only oxidized as 20 and has relatively low reducing ability.
It is divided into those that have a mild reaction. Therefore, it is possible to create detailed regulations (goods) by combining the two.

As a result of Example 3, it was found that Al is particularly easy to use as a representative of the former, and Cu is particularly easy to use as a representative of the latter.

Therefore, TeO2 was mixed with Al and Cu at different mixing ratios, and heat treated for 2 hours at 700°C in an N2 gas atmosphere to obtain a dark brown sintered body. These sintered size 20o
As a result of heating with a heater in a vacuum of 10" Torr using q, a film with characteristics corresponding to slight changes in the mixing ratio was obtained. This result was irradiated with a semiconductor laser and investigated in detail. Then, the mixing ratio Xγ of A1 and the mixing ratio Xδ of Cu
However, 16≦Xγ≦60. Ka2゜≦Xδ≦6omo1%
%, and when mixing two components at the same time, 5o≦XI
It has been found that a thin film particularly suitable for optical information recording properties can be obtained in the region of +Xδ≦s□mo1%.

Example 5 Among the sintered bodies obtained in Example 4, the starting composition was (TeO2)
A sintered body of so(Al)5o(Cu)+o mo1% was selected and pulverized to powder. This powder was weighed to about 2 g and pressed into pellets with a diameter of 20+11 J and a thickness of about 15 J using the jig shown in FIG. Press pressure is 5t
/CJ.

When these pellets were deposited on a Pyrex glass substrate, one by heater heating and the other by electron beam heating, a slightly yellowish-brown TeOx thin film was obtained. These two types of films were heated at 50'C.
When the film was left in a constant temperature and humidity chamber at 90H% and its transmittance changes were periodically examined, as shown in Figure 8, the film exposed to the electron beam showed less change than film a heated by the heater. , was found to be less affected by humidity and more stable.

Example 6 1 B:' 1, 1 t, 200φ P rotating at 1601TITl
Using the electron beam system used in Example 5, pellets having a starting composition of Te023oA13o[40] were deposited on an MMA resin base material to a thickness of about 120 mm at a rate of 3 people/sec.
A thin film of TeOx (o<x<2) was deposited on the substrate to fabricate an optical disk.

Using this disk, a recording experiment was conducted in a system as shown in FIG. The light emitted from the semiconductor laser 39 passes through the first lens 3
7, it becomes a pseudo-parallel light 40, which is shaped into a round shape by the second lens 36, becomes parallel light again by the third lens 35, passes through the half mirror 33, and is passed through the fourth lens 31 to a wavelength limit of approximately 0.8μ. The light is focused on a spot 42 with a size of .

The recording film on the disk 30 irradiated by this circular spot is transformed into black and recording is performed. Here, the semiconductor laser can be modulated to record information signals on the disk.

The signal is detected by detecting the reflected light 41 from the disk surface 3o...
- received through the mirror 32 and performed with a photosensitive diode through the lens 34;

Recording was performed by modulating a 19'' semiconductor laser beam with 5 single frequencies and irradiating the disk surface rotating at 18oO- with an irradiation power of 8mW.The C/N was measured using a spectrum analyzer. , 60dB was obtained.

Effects of the Invention As described above, according to the present invention, compared to the conventional method of manufacturing a tellurium low oxide thin film.

(1) Excellent reproducibility of properties (2) Less likely to cause composition deviations (3) No dropouts due to bumping (4) Less humidity deterioration (5) Control of properties, easy vapor deposition, etc. A tellurium low oxide thin film having the following characteristics can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing how starting materials are mixed in one step to obtain a sintered body as a vapor deposition source of the present invention;
The figure is a perspective view of the mixed powder before sintering, Figure 3 is a sectional view of the electric furnace used for sintering, and Figure 4 is a sectional view of an apparatus for manufacturing a tellurium low oxide thin film using the sintered body of the present invention. 5 is a perspective view showing one form of pelletized vapor deposition source, FIG. 6 is a sectional view of a jig made by pressing the pellets, and FIG. 7 is a low tellurium oxide thin film obtained by the present invention. FIG. 8 is a diagram showing the difference in moisture resistance due to different deposition methods of tellurium low oxide thin film, and FIG. 9 is a diagram showing information signals recorded on an optical disk formed by the manufacturing method of the present invention. - It is a schematic diagram of a device for reproduction. 24... Semiconductor laser, 25... Laser light, 26... Objective lens 1.27...
・Objective lens 2.28...TeOx thin film, 29
······Base material. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 1 (/ 13 /? 4 7 5 7〆Figure 5 □ Figure 6 Figure 7 Figure 8 / /l/ //l)

Claims (1)

[Claims] (1) Al and Si as reducing substances to tellurium dioxide
, Ti. V, W, Or, Mn, Fe, Go, Ni,
Cu, Zn, Ge, Mo. Cd, In, Sn, Sb, Ta, Bi, P
b (7) Te021TeO21oo-x by mixing a metal, a metalloid, or at least one of S, Se, and C.
a<xa≦8omo1%, M is a reducing substance M1+ M2
+...2Mn aggregate x1+x2+...
...+xn=xα) to obtain a sintered body containing tellurium dioxide in a partially reduced form, and this sintered body is heated in vacuum to transfer optical information onto the substrate. A method for producing a low tellurium oxide thin film, which comprises forming a low tellurium oxide thin film TeOxβ (0<Xβ<2) as a recording medium. (2) Addition amount of reducing substance is 15×α≦s o mo
The method for producing a low tellurium oxide thin film according to claim 1, wherein the tellurium content is 1%. (3) As reducing substances, Cu, Sb, Pb, A
l, In, Zn. 2. The method for producing a low tellurium oxide thin film according to claim 1, characterized in that at least one reducing substance selected from 2'Bi, Ge, Se, and Cd is used. (4) The method for manufacturing a low tellurium oxide thin film according to claim 1, characterized in that Cu and Al are selected as reducing substances and mixed at the same time. (5) The composition ratios Xy+Xδ of Al and Cu are each 16≦Xγ≦50120≦Xδ≦60.50≦Xγ+X
5. The method for producing a low tellurium oxide thin film according to claim 4, wherein δ≦8°mo1%. (6) The method for producing a low tellurium oxide thin film according to claim 1, wherein the heat treatment is performed in an inert gas. C7) The method for producing a low tellurium oxide thin film according to claim 1, characterized in that the heat treatment is carried out at a temperature between 400°C and 100°C. (8) The method for producing a low tellurium oxide thin film according to claim 1, characterized in that the degree of vacuum is set to about 1×10 Torr or less. (9) Al and Si as reducing substances to tellurium dioxide
, Ti. V, W, Cr, Mn, Fe, Go
, Ni, Cu, Zn, Ge, Mo
. Cci, In, Sn, Sb, Ta metal, metalloid dimensions are S. By mixing at least one of Ss and C, TeO2M
xα(0<Xa<s Omo1%1M is reducing 1o
Heat treatment is performed on the aggregate of the o-xa substances Ml + M2 +...2Mn in the form of After pulverizing this sintered body and shaping it under pressure, the resulting object was heated in a vacuum to form a tellurium low oxide thin film as an optical information recording medium on a substrate. TeOxβ(○〈Xa
A method for producing a low tellurium oxide thin film, which comprises forming <2). (10) Al and S as reducing substances to tellurium dioxide
i, Ti. V, W, Or, Mn, Fe, Go, Ni, 011. Zn
, Ge, Mo. Cd, In, Sn, Sb, Ta metal, metalloid 1 fc is S. By mixing at least one of Se and C, TeO2M
Xa (0<xa<somo1%, M is reducing +0O-
Xa substance M1+ M2 +...2Mn aggregate x
1+x2+...+
After crushing this sintered body, the object obtained by pressure shaping is heated in a vacuum using an electron beam, and a tellurium-free material is deposited on a substrate as an optical information recording medium. A method for producing a low tellurium oxide thin film, which comprises forming an oxide thin film TeOxβ (○kuxa<2).