JPS62139877A - Formation of deposited film - Google Patents

Abstract

PURPOSE:To form a deposited film having uniform characteristics over a wide area by bringing a gaseous raw material contg. chalcogenide atoms and gaseous halogen oxidizing agent into contact and using the formed precursors in the excited state as a supply source. CONSTITUTION:Gaseous SeH2, etc., in a cylinder 101 and gaseous AsH3, etc., in a cylinder 102 as the gaseous raw material contg. chalcogenide atoms are introduced together with the gaseous halogen oxidizing agent such as gaseous F2 in a cylinder 106 into a vacuum chamber 102. These gaseous raw materials are mixed and bombarded to form the plural precursors contg. the precursors in the excited state. At least one of such precursors in used as the supply source for the film constituting element and the amorphous film such as AsxSe(1-x) (where x=0.42), etc., is deposited on a substrate 118. The film having excellent physical characteristics and high quality is formed with the conserved energy by the above-mentioned method.

Description

[Detailed Description of the Invention] [Prior Art] Unexploited UP is a defective or crystalline functional thin film such as a semiconductor film, an insulator film, or a conductor film, especially an active or passive semiconductor device. , a substrate 1h1 useful for applications such as optical semiconductor devices, solar cells, and photosensitive devices for electrophotography.
Regarding each formation method.

Vacuum evaporation method, plasma CVD method, thermal CVD method, optical DVD method 1 reactive sputtering method, ion blating method, etc. have been tried to form the deposited film, and in general, plasma CVD method is widely used. It has become a corporate entity.

However, since the deposited films obtained by these deposited film formation methods are required to be applied to electronic devices and optoelectronic devices that require more advanced functions, they have improved electrical and optical properties and durability during repeated use. There is room for further improvement in comprehensive properties in terms of productivity and mass production, including fatigue properties, use environment properties, uniformity and reproducibility.

Among these, it is currently considered best to form chalcogenide films by heating vacuum evaporation, since it is possible to develop electrical and optical properties that fully satisfy each application. ing.

However, depending on the application of the deposited film, it is necessary to fully satisfy the requirements of large area, uniformity of film thickness, and uniformity of film quality, and mass production with reproducibility. Forming a deposited film using a method requires high vacuum and a large investment in equipment for mass production.The control items for mass production also become complex, the tolerance for control becomes narrow, and the adjustment of the equipment is delicate. From a certain point, these have been pointed out as problems that should be improved in the future.

As described above, in the formation of functional films, there is a strong desire to develop a method for forming deposited films that can be mass-produced using low-cost equipment while ensuring practical properties and maintaining uniformity.

〔the purpose〕

An object of the present invention is to eliminate the drawbacks of the above-mentioned method for forming a deposited film, and at the same time to provide a new method for forming a deposited film that does not rely on conventional methods.

Another object of the present invention is to provide a method for forming a deposited film that saves energy, allows easy control of film quality, and provides a deposited film with uniform characteristics over a large area.

Still another object of the present invention is to provide a method for forming a deposited film that is highly productive and mass-producible, and can easily produce a film with high quality and excellent physical properties such as electrical, optical, and semiconductor properties. be.

[Means for solving problems]

The method for forming a deposited film of the present invention that achieves the above object introduces into a reaction space a gaseous raw material for forming a deposited film and a gaseous halogen-based oxidizing agent having the property of oxidizing the raw material. The method is characterized in that a precursor in an excited state is generated by chemically contacting the deposited film with the precursor being used as a source of a deposition film component to form a deposited film on a substrate located in a film forming space. .

[Effect]

According to the deposited film forming method of the present invention described above, it is possible to save energy, increase the area, uniformity of film thickness, and uniformity of film quality, simplify management and mass production, and save a lot of money on mass production equipment. It does not require major capital investment, the control items for mass production become clear, the control tolerance is wide, and equipment adjustment becomes easy.

In the deposited film forming method of the present invention, the gaseous raw material used for forming the deposited film is oxidized by chemical contact with a gaseous halogen-based oxidizing agent, and the target deposit A Type of M.

In the present invention, the above-mentioned gaseous raw material and gaseous halogen-based oxidizing agent may be selected as desired depending on the characteristics, application, etc. In normal cases, it can be a gas, liquid, or solid.

When the raw material for forming the deposited film or the halogen-based oxidizing agent is liquid or solid, Ar.

He, N2. A carrier gas such as I2 is used, and bubbling is performed while adding heat if necessary, to introduce a raw material for forming a deposited film and a halogen-based oxidizing agent into the reaction space in gaseous form.

At this time, the partial pressure and mixing ratio of the gaseous raw material and the gaseous halogen-based oxidizing agent can be adjusted by adjusting the flow rate of the carrier gas or the vapor pressure of the raw material for forming the deposited film and the gaseous halogen-based oxidizing agent. Set.

As raw materials for forming a deposited film used in the present invention, for example, if a chalcogenide deposited film is to be obtained, hydrides, chlorides, organometallic compounds, etc. of chalcogenide elements are effective. It can be mentioned as a thing.

Specifically, as a Se-based compound, SeH2゜5eCu
2. Se (CH3)2, Se (C2H5)2,5
e2Br2 etc. can be mentioned as an effective raw material.

As S-based compounds, SI2, SCC20s2c sentence 2
．． SOC standing 2. SF6 and the like can be cited as effective raw materials.

Examples of Te-based compounds include TeI2, Te(CH3)2
, Te (C2H5)2, etc. can be mentioned as effective raw materials.

As-based compounds include AsH3 and AsCl3.

AsBr3, As(CHS)3, As(C2
H5)3, AS (CeHs)3, AS (oc
H3)3, AS (OC2H5)3, As (O
C3H7)3, As (OC4H9) 3ft, etc. can be cited as effective raw materials.

Of course, these raw materials can be used not only alone, but also as a mixture of two or more.

The halogen-based oxidizing agent used in the present invention is in a gaseous state when introduced into the reaction space.

At the same time, it has the property of effectively oxidizing the gaseous raw material for forming a deposited film introduced into the reaction space through chemical contact alone.F2°C12, Br2. Effective examples include halogen gas such as I2, nascent fluorine, chlorine, and bromine.

These halogen-based oxidants are in gaseous form, and are introduced into the reaction space together with the gaseous raw material for forming the deposited film at a desired flow rate and supply pressure, and mixed and collided with the raw material. The raw material is brought into contact with the raw material and oxidized to efficiently generate a plurality of types of precursors including excited state precursors. The excited state precursors and other precursors that are generated serve as a source of components for the deposited film in which at least one of them is formed.

The precursors produced may decompose or react to form another excited state precursor or a precursor in another excited state, or may optionally be formed in the form IE, albeit releasing energy. A deposited film with a three-dimensional network structure is created by touching the surface of the substrate disposed in the film space.

In the present invention, the type of raw materials and halogen-based oxidizing agent are used as film-forming factors so that the deposition process can proceed smoothly and a film with high quality and desired physical properties can be formed. The mixing ratio, the pressure during mixing, the flow rate, the internal pressure of the film forming space, the flow rate of gas, and the film forming temperature (substrate temperature and ambient temperature) are appropriately selected as desired.

These film-forming factors are organically related and are not determined independently, but are determined depending on each other in relation to each other.

In the present invention, the ratio of the amounts of the gaseous raw material for forming a deposited film and the gaseous halogen-based oxidizing agent introduced into the reaction space is determined based on the relationship between the film-forming factors and the intermediate speed of the above-mentioned film-forming factors. Although it can be determined as desired, the introduction Ii, the quantitative ratio,
Preferably, the ratio is suitably 1/20 to too/1, more preferably 115 to 50/1.

The pressure at the time of mixing when introduced into the reaction space is preferably higher in order to increase the probability of chemical contact between the gaseous raw material and the gaseous halogen-based oxidizing agent. It is preferable to determine the optimum value as desired by considering the following.

The pressure at the time of mixing is determined as described above, but the pressure at the time of each introduction is preferably lXl0-
It is desirable that the pressure be 7 atm to 10 atm, more preferably I x 10-6 atm to 3 atm.

The pressure in the film-forming space, that is, the pressure in the space where the substrate on which the film is to be formed is disposed, is the pressure of the excited state precursor (E) generated in the reaction space and, if necessary, the precursor. The precursor (D) derived from the precursor (E) is appropriately set as desired so as to effectively contribute to film formation.

When the film forming space is open and continuous with the reaction space, the internal pressure of the film forming space is the pressure introduced into the reaction space between the substrate-like raw material for forming the deposited film and the gaseous halogen oxidant. In relation to the flow rate, it is possible to adjust the flow rate by, for example, using a differential exhaust system or a large exhaust system.

Alternatively, if the conductance of the connection between the reaction space and the film-forming space is small, an appropriate exhaust system may be provided in the film-forming space.
By controlling the exhaust volume of the device, the pressure in the film forming space can be adjusted.

In addition, if the reaction space and film-forming space are integrated and the reaction position and film-forming position are only spatially different, use differential pumping as described above or use a large-scale pump with sufficient exhaust capacity. It is best to install an exhaust system.

As described above, the pressure in the film forming space is determined based on the relationship between the gaseous raw material introduced into the reaction space and the pressure of introduction of the gaseous/X-rogen oxidizing agent, and is preferably 0.0
OITorr~to.

Torr, more preferably 0.0ITorr to 3
It is desirable to set it to 0 Torr, most preferably 0.05 to 10 Torr.

Regarding the flow rate of the gas, when the raw material for forming the deposited film and the halogen-based oxidizing agent are introduced into the reaction space, they are mixed uniformly and efficiently, and the precursor (E) is efficiently The geometrical arrangement of the gas inlet, the substrate, and the gas outlet must be designed in consideration of the geometric arrangement of the gas inlet, the substrate, and the gas outlet so that the gas can be generated and the film can be formed properly without any problems. One preferred example of this geometry is shown in FIG.

The substrate temperature (Ts) during film formation is set as desired depending on the type of gas used, the number of types of deposited film to be formed, and the required characteristics. The temperature is preferably from room temperature to 200°C, more preferably from room temperature to 100'C, especially when forming a chalcogenide compound deposited film with better properties such as semiconductivity and photoconductivity. is the substrate temperature (Ts)
It is desirable that the temperature is between room temperature and 70°C. In addition, when obtaining a polycrystalline film, preferably 100 to zoo'c,
More preferably, the temperature is 100 to 150°C.

As for the atmospheric temperature (Tat) in the film forming space.

The substrate temperature (Ts) is adjusted so that the precursor (E) and the precursor (D) to be generated do not change into chemical species unsuitable for film formation, and the precursor (E) is efficiently generated. It can be determined as desired in relation to the above.

The substrate used in the present invention may be electrically conductive or electrically insulating, as long as it is appropriately selected depending on the intended use of the deposited film to be formed. Examples of the conductive substrate include NiCr, Steer L/S, AM, C
r, Mo.

Examples include metals such as Au, Ir, Nb, Ta, V, Ti, Pt, and Pd, and alloys thereof.

As the electrically insulating substrate, films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, glass, ceramic, paper, etc. are usually used. Preferably, at least one surface of these electrically insulating substrates is subjected to a conductive treatment, and another layer is preferably provided on the conductive treated surface side.

For example, if it is glass, its surface may be NiCr, AI, or C.
r, Mo, Au, I r, Nb, Ta, V, Ti, Pt
, Pd, In2O3,5n02, ITO(I n203
+5no2) etc.? NiCr, Ai, Ag, Pb, Zn, Ni
, Au, Cr, Mo, Ir, Nb
, Ta, V.

The surface is treated with a metal such as Ti or Pt by vacuum evaporation, electron beam evaporation, sputtering, etc., or laminated with the metal to make the surface conductive. The shape of the support may be any shape, such as a cylinder, a belt, or a plate, and the shape is determined according to desire.

The substrate is preferably selected from the above in consideration of the adhesion and reactivity between the substrate and the membrane. Furthermore, if the difference in thermal expansion between the two is large, a large amount of distortion will occur in the film, and a good quality film may not be obtained.

It is preferable to select and use substrates whose thermal expansion differences are close to each other.

In addition, the surface condition of the substrate is directly related to the structure (orientation) of the film and the occurrence of cone-shaped structures, so it is important to treat the surface of the substrate so that it has a film structure and structure that provides the desired properties. is desirable.

FIG. 1 shows an example of an apparatus suitable for implementing the deposited film forming method of the present invention.

The deposited film forming apparatus shown in FIG. 1 is roughly divided into three parts: an apparatus main body, an exhaust system, and a gas supply system.

The apparatus main body is provided with a reaction space and a film forming space.

101 to 108, 128 and 129 are cylinders filled with gas used in film formation, and 101a
~108a, 128a.

129a are gas supply pipes, 101b to 108b,
128b and 129b are mass flow controllers for adjusting the flow rate of gas from each cylinder, respectively, and 101C to 108c.
, 128c.

129C are gas pressure gauges, 101d to 108d1
28d, 129d and 1O1e-108e, 128e
, 129e are valves respectively.

101f, N108f, 128f, and 129f are pressure gauges that indicate the pressure inside the corresponding gas cylinder, respectively.

Reference numeral 120 denotes a vacuum chamber, which has a structure in which a pipe for introducing gas is provided at the upper part and a reaction space is formed downstream of the pipe.
It has a structure in which a film forming space is formed in which a substrate holder 112 is provided such that a substrate holder 18 is installed therein. The gas introduction pipes have a triple concentric arrangement structure, with a first gas introduction pipe 109 into which gas from gas cylinders 101 and 102 is introduced, and a second gas introduction pipe into which gas from gas cylinders 103 to 105 is introduced. waste introduction pipe 110 and gas cylinder 1
It has a third gas introduction pipe 111 into which gases from 06 to 108, 128, and 129 are introduced.

Each gas introduction tube is designed to discharge gas into the reaction space so that the inner tube is located further away from the surface of the substrate. In general, the gas introduction pipes are arranged so that the outer pipes surround the inner pipes.

Gas is supplied from the tube cylinder to each introduction pipe through gas supply pipelines 123 to 125, respectively.

Each gas introduction pipe, each gas supply pipeline, and the vacuum chamber 120 are evacuated via the main vacuum valve 119 by a vacuum evacuation device (not shown).

The base body 118 is installed at a desired distance from the position of each gas introduction pipe by moving the base body holder 112 up and down.

In the case of the present invention, the distance between the substrate and the gas outlet of the gas inlet pipe is determined appropriately by taking into consideration the type of deposited film to be formed, its desired characteristics, gas flow rate, internal pressure of the vacuum chamber, etc. It can be determined as desired, but preferably several mm to 2
It is desirable that the length be 0 cm, more preferably about 5 mm to 15 cm.

Reference numeral 113 denotes a substrate heater that heats the substrate 118 to an appropriate temperature during film formation, preheats the substrate 118 before film formation, and further heats the substrate 118 to anneal the film after film formation. be.

The base heater 113 is connected to a power source 115 by a conductor 114.
Power is supplied by

116 is a thermocouple for measuring the substrate temperature (Ts), and is electrically connected to the temperature display device 117.

Hereinafter, the present invention will be specifically explained according to Examples.

Example 1 A deposited film was formed using the film forming apparatus shown in FIG. 1 under the conditions shown in Table 1.

SeH2 gas filled in the pump 101 at a flow rate of 7
A which is also filled in the pump 102 with S c Cm
sH3 gas is supplied from the gas introduction pipe 109 at a flow rate of 14 seconds, and F2 gas filled in the pump 106 is supplied at a flow rate of 20 seconds.
He gas filled in the CCml pump 107 is introduced into the vacuum chamber 1 from the gas introduction pipe 111 at a flow rate of 405 CCm.
It was introduced in 2002.

At this time, the pressure inside the vacuum chamber 120 was adjusted to 800 mTorr by adjusting the opening/closing degree of the vacuum valve 119. The base was made of stone-covered glass (15 cm x 15 cm), and the distance between the gas inlet 111 and the base was set to 3 cm.

The substrate temperature (Ts) was set at 60' as shown in Table 1.

When gas was allowed to flow in this state for 56 minutes, an AsxSe (1-x) (x=0.42) film having the thickness shown in Table 1 was deposited on the substrate.

Moreover, the unevenness in film thickness distribution was within ±5%.

It was confirmed that all the samples of the AsxSe (1-x) (x=0.42) film formed were amorphous by electron beam diffraction.

Amorphous AsxSe (1-x) (x=0.42) for each sample
)I+! A comb-shaped electrode (gap length 200
JLm) was vapor-deposited to prepare a sample for conductivity measurement. Each sample was placed in a vacuum cryostat, a voltage of 100 V was applied, the current was measured with a microcurrent meter (YHP414OB), and the dark conductivity (a-d) was determined. Also, 600 nm, 0.
The photoconductivity (σP
) was sought. Furthermore, the optical band gap (EcOPt) was determined from the absorption of light. These results are shown in Table 1.

Example 2 A deposited film was formed using the film forming apparatus shown in FIG. 1 under the conditions shown in Table 2.

The film formation procedure and evaluation of the deposited film were performed in the same manner as in Example 1. The results shown in Table 2 were obtained.

Example 3 A deposited film was formed using the film forming apparatus shown in FIG. 1 under the conditions shown in Table 3.

The film formation procedure and evaluation of the deposited film were performed in the same manner as in Example 1. The results shown in Table 3 were obtained.

Example 4 A deposited film was formed using the film forming apparatus shown in FIG. 1 under the conditions shown in Table 4.

The film formation procedure and evaluation of the deposited film were performed in the same manner as in Example 1. The results shown in Table 3 were obtained.

Table 1 Table 2 Table 3 Table 4 [Effects] From the above detailed explanation and each example, the deposited film forming method of the present invention can save energy and at the same time easily control film quality. A deposited film with uniform physical properties over a large area can be obtained. In addition, it has excellent productivity and mass production, and is of high quality and electrical.
A film with excellent physical properties such as optical and semiconductor properties can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a film forming apparatus used in an example of the present invention. 101 to 108, 128, 129 1------ Gas cylinder, 101a N108a to 128a, 129a---111---Gas introduction pipe, 101b, 108b, 128b, 129b--- --1----Mass flow meter, 101c N108c,
128c, 129c-1111---Gas pressure gauge. 101d-108d, 128d, 129d and 10
1e to 108e, 128e,
129e-11------ Valve, 101f-108f, 128f, 129f------
1---Pressure gauge, 109, 110, 111---Gas introduction pipe. 112---------One base holder. 113---------Heater for heating one substrate, 11
6-------Thermocouple for monitoring substrate temperature. 118------One base, 119---Continuous air exhaust valve. respectively.

Claims (10)

[Claims] (1) By introducing a gaseous raw material containing chalcogenide atoms for forming a deposited film and a gaseous halogen-based oxidizing agent having the property of oxidizing the raw material into a reaction space and bringing them into contact with each other. chemically generating a plurality of precursors including excited state precursors, and using at least one of the precursors as a source of a deposited film component to deposit a deposited film on a substrate in a deposition space; A deposited film forming method characterized by forming a deposited film. (2) The deposited film forming method according to claim 1, wherein the gaseous raw material is a hydride. (3) The deposited film forming method according to claim 1, wherein the gaseous raw material is an organic metal. (4) The deposited film forming method according to claim 1, wherein the gaseous halogen-based oxidizing agent includes halogen gas. (5) The deposited film forming method according to claim 1, wherein the gaseous halogen-based oxidizing agent contains fluorine gas. (6) The deposited film forming method according to claim 1, wherein the gaseous halogen-based oxidizing agent includes chlorine gas. (7) The deposited film forming method according to claim 1, wherein the gaseous halogen-based oxidizing agent is a gas containing fluorine atoms as a constituent component. (8) The deposited film forming method according to claim 1, wherein the gaseous halogen-based oxidizing agent contains halogen in a nascent state. (9) The deposition according to claim 1, wherein the substrate is disposed at a position opposite to the direction in which the gaseous raw material and the gaseous halogen-based oxidizing agent are introduced into the reaction space. Film formation method. (10) The deposited film forming method according to claim 1, wherein the gaseous raw material and the gaseous halogen-based oxidizing agent are introduced into the reaction space from a transport pipe having a multi-tube structure.