JP2000183354A - Manufacture of thin-film transistor and continuous film- forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationalize a manufacturing process, without deteriorating the characteristics of a bottom gate thin-film transistor. SOLUTION: For manufacturing a thin-film transistor, a gate electrode forming process for forming a gate electrode on an insulating substrate 70 is executed. A continuous film-forming process for supplying the insulating substrate 70, where the gate electrode is formed to the reaction room 12 of a film forming device, forming a gate oxide film with a chemical vapor phase growing method, and forming a semiconductor thin film by overlapping it on the gate oxide in the same reaction room 12 is executed. Then, an implanting process for selectively implanting impurities to the semiconductor thin film and forming a source area and a drain region is executed. In the continuous film-forming process, first reaction gas containing an oxygen element is introduced to the reaction room, the gate oxide film is stacked by chemical vapor phase growing, the reaction room 12 is vacuum-sucked, first reaction gas is exhausted, second reaction gas which does not contain the oxygen element is made to flow into the reaction room 12, the remainder of first reaction gas is diluted, and the semiconductor thin film is stacked with chemical vapor phase growing by using second reaction gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a thin film transistor and a continuous film forming apparatus. More specifically, the present invention relates to a technique for continuously forming a gate oxide film and a semiconductor thin film in a bottom-gate thin film transistor in which a gate electrode, a gate oxide film, and a semiconductor thin film are stacked in order from the bottom.

[0002]

2. Description of the Related Art A bottom gate type thin film transistor is formed on an insulating substrate, and has a laminated structure in which a gate electrode, a gate oxide film, and a semiconductor thin film are sequentially stacked from the bottom. For example, the gate electrode is made of a metal such as molybdenum, the gate oxide film is made of silicon dioxide (SiO ₂ ), and the semiconductor thin film is made of amorphous silicon or polycrystalline silicon. For example, when an inexpensive glass plate is used as the insulating substrate, it is necessary to form the above-described laminated structure at a relatively low temperature. For example, a gate oxide film and a semiconductor thin film have been formed using a plasma enhanced chemical vapor deposition method.

[0003]

SUMMARY OF THE INVENTION As a gate oxide film,
When forming silicon oxide, for example, SiH_Four And N
_Two Introducing a reaction gas consisting of a mixture of O into the deposition chamber
And in a plasma state with high frequency applied,
SiO on insulating substrate_Two Is deposited. Also, semiconductor thin
When forming amorphous silicon as a film, for example, Si
H_Four Reaction gas consisting of
Insulating substrate made of glass etc.
Deposit Si atoms on the plate. Conventionally, the gate oxide film
Silicon dioxide and amorphous silicon as a semiconductor thin film
They were formed in separate film forming chambers. If the same film formation
When trying to form in a chamber,_Two When forming a film
Reaction gas (SiH_Four, N_Two O) remains amorphous
This is because it has an adverse effect when forming high quality silicon. Special
When oxygen atoms are incorporated into amorphous silicon
Low mobility of thin film transistor using recon as active layer
It will get worse. For this reason, the conventional gate oxide film and semiconductor thin film
The films were formed in separate deposition chambers. However
In this method, the substrate is transferred every time the deposition chamber is switched.
And the deposition chamber needs to be evacuated.
Is worse). Also, SiO_Two Chamber
When the substrate is transferred to the chamber where Si is deposited, SiO
_Two Surface is exposed to the atmosphere. As a result, SiO_Two And S
H at the interface of i_Two An adsorption layer such as O is formed, and the interface characteristics
There is a disadvantage that it gets worse.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, an object of the present invention is to rationalize the manufacturing process without deteriorating the characteristics of a bottom gate type thin film transistor. In order to achieve this purpose, the following measures were taken. That is, the method for manufacturing a thin film transistor according to the present invention includes a gate electrode forming step of forming a gate electrode on an insulating substrate, and placing the insulating substrate on which the gate electrode is formed into a reaction chamber and performing a gate by chemical vapor deposition. Forming an oxide film, further forming a semiconductor thin film over the gate oxide film in the same reaction chamber, and forming a source region and a drain region by selectively implanting impurities into the semiconductor thin film; And an injection step. Preferably, in the continuous film forming step, after introducing a first reaction gas containing an oxygen element into the reaction chamber and depositing a gate oxide film by chemical vapor deposition, the first reaction gas is evacuated by evacuation of the reaction chamber. After evacuating and further flowing a second reaction gas containing no oxygen element into the reaction chamber to dilute the remainder of the first reaction gas, a semiconductor thin film is deposited by chemical vapor deposition using the second reaction gas. Preferably, in the continuous film forming step, a gate oxide film made of SiO ₂ is formed by using a first reaction gas containing SiH ₄ and N ₂ O;
Forming a semiconductor thin film made of Si with a second reaction gas containing H _4.

Further, according to the present invention, after a gate electrode is formed on an insulating substrate, the gate electrode is put into a reaction chamber, a gate oxide film is formed by a chemical vapor deposition method, and the gate oxide film is formed in the same reaction chamber. A thin film transistor having a stacked structure in which a semiconductor thin film is formed by stacking, wherein an oxygen concentration of the semiconductor thin film is controlled to 1 × 10 ²⁰ / cm ³ or less. Preferably, the trap density at the interface between the gate oxide film and the semiconductor thin film is controlled to 3 × 10 ¹¹ / cm ² or less.

Further, the present invention provides a reaction chamber capable of evacuating,
A continuous film forming apparatus including an electrode to which a high frequency is applied and a stage on which a substrate to be processed is placed, wherein a first reaction gas containing an oxygen element is introduced into a reaction chamber to oxidize while applying a high frequency. After depositing the film, a second reaction gas containing no oxygen element is introduced into the same reaction chamber to deposit a semiconductor thin film, so that the material in the reaction chamber including the electrode is non-adsorbing to the first reaction gas. It is characterized by being. Preferably, the continuous film forming apparatus includes a plurality of reaction chambers, each of which performs a continuous film formation of an oxide film and a semiconductor thin film independently of each other.

Further, the present invention comprises a pair of insulating substrates joined to each other via a predetermined gap and an electro-optical material held in the gap, and one of the insulating substrates has a pixel electrode and a thin film transistor for driving the pixel electrode. Is formed, and a counter electrode is formed on the other insulating substrate, wherein a gate electrode is formed on the one insulating substrate to form the thin film transistor. A step of forming a gate oxide film by a chemical vapor deposition method by introducing the insulating substrate on which the gate electrode is formed into a reaction chamber, and further forming a semiconductor thin film over the gate oxide film in the same reaction chamber. A film step and an implantation step of selectively implanting impurities into the semiconductor thin film to form a source region and a drain region are performed.

According to the present invention, when fabricating a thin film transistor having a bottom gate structure, a gate oxide film and a semiconductor thin film are continuously formed in the same reaction chamber. This allows
The interface characteristics between the gate oxide film and the semiconductor thin film are improved, and the manufacturing process is rationalized. In particular, in order to maintain the film quality of the semiconductor thin film and remove oxygen atoms from the film as much as possible, the material in the reaction chamber is made of a material that is non-adsorbing to a reaction gas containing oxygen atoms. Also, after depositing a gate oxide film using a reaction gas containing an oxygen element, the reaction chamber was once evacuated and evacuated, and another reaction gas containing no oxygen element was flowed into the reaction chamber and used earlier. After diluting the residue of the reaction gas,
The semiconductor thin film is deposited using a reaction gas containing no oxygen element.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing a basic configuration of a continuous film forming apparatus according to the present invention. This continuous film forming apparatus basically includes the film forming chamber 1 as a main component. The film forming chamber 1 comprises a reaction chamber 12 which can be evacuated, and an electrode 13 for applying a high frequency therein.
And a stage 1 on which an insulating substrate 70 to be processed is placed
4 are stored. An introduction pipe 14 is connected to an upper part of the electrode 13 in a nozzle shape, and a desired reaction gas is introduced through a valve. A high frequency power supply 19 is
Are connected, and a high frequency is applied to the electrode 13. On the other hand, the stage 14 is held at the ground potential, and a heater 15 for heating the insulating substrate 70 is stored inside the stage 14. The insulating substrate 70 to be processed is the gate valve 16
Through the reaction chamber 12. After the processing is completed, the insulating substrate 70 is taken out through the gate valve 16. The insulating substrate 70 is placed on the stage 14 housed in the reaction chamber 12, and a high frequency power is supplied from the high frequency power supply 19 while supplying a desired reaction gas into the reaction chamber 12 from the nozzle-shaped electrode 13 opposed thereto. When applied to the upper plate electrode 13, plasma is generated, and a desired film is formed on the insulating substrate 70. At this time, the stage 14 is heated by the heater 15 to keep the insulating substrate 70 at a predetermined temperature.

In the present invention, the gate oxide film and the semiconductor thin film are continuously formed by using the film forming chamber 1. First, an oxide film is deposited on the insulating substrate 70 while introducing a first reaction gas containing an oxygen element into the reaction chamber 12 and applying a high frequency, and then a second reaction gas containing no oxygen element is supplied to the same reaction chamber. 12 to deposit a semiconductor thin film. At this time, the material in the reaction chamber 12 including the upper plate electrode 13 is made of a material that is non-adsorbable to the first reaction gas, and the entry of oxygen element into the semiconductor thin film is prevented as much as possible. For example, porous alumina or the like is conventionally used for the upper plate electrode 13, but in the present invention, for example, mirror-finished aluminum is used instead.

In the above-described continuous film forming process, a first reaction gas containing an oxygen element is introduced into the reaction chamber 12 to deposit a gate oxide film by chemical vapor deposition, and then the inside of the reaction chamber 12 is evacuated once. Exhaust the first reaction gas. Thereafter, a second reaction gas containing no oxygen element is further passed through the exhausted reaction chamber 12 to sufficiently dilute the residue of the first reaction gas (purge), and then a chemical vapor using the second reaction gas is used. A semiconductor thin film is deposited by growth. By using such vacuuming and purging together, the incorporation of oxygen element into the semiconductor thin film is prevented.
Specifically, a gate oxide film made of SiO ₂ is formed using a first reaction gas containing SiH ₄ and N ₂ O,
A semiconductor thin film made of Si is formed using a second reaction gas made of H ₄ . At this time, the plasma output of the high frequency power supply 19 is set to, for example, 2 kW to deposit SiO ₂ .
Further, in order to deposit a semiconductor thin film made of Si, the plasma output of the high frequency power supply 19 is set to, for example, 1.5 kW.

In the above-described continuous film forming step, the oxygen concentration of the semiconductor thin film made of silicon could be suppressed to 1 × 10 ²⁰ / cm ³ or less by using both vacuum evacuation and purging. Without this evacuation and purging, the oxygen concentration in the semiconductor thin film will exceed 2 × 10 ²⁰ / cm ³ . Further, by changing the electrode 13 in the reaction chamber 12 from aluminum to aluminum, the oxygen concentration in the silicon semiconductor thin film could be reduced to 3 × 10 ¹⁹ / cm ³ . This concentration is substantially equal to the oxygen concentration in the semiconductor thin film when the gate oxide film and the semiconductor thin film are formed in different chambers. In addition, by continuously forming the gate oxide film and the semiconductor thin film, the trap density at the interface between the ^two could be controlled to 3 × 10 ¹¹ / cm ² or less. On the other hand, when the gate oxide film and the semiconductor thin film are formed in different chambers, the trap density at the interface reaches 1 × 10 ¹² / cm ² .

FIG. 2 is a schematic perspective view showing an example of the entire configuration of the continuous film forming apparatus according to the present invention. The film forming apparatus is roughly divided into a main body, a film forming system, and a substrate feeding section. The body is 4
It includes a film forming chamber 1, a load lock chamber 6, an unload lock chamber 8, and a heating chamber 2. The film forming system includes a gas supply system 61, a main body control rack 62, a remote heat exchanger module 63, a main body pump module 64, a process pump module 65, and the like. This film forming system is connected to each of the film forming chambers 1 of the main body, and performs processing required for plasma enhanced chemical vapor deposition. The substrate supply unit includes an automatic cassette load station 3 that handles a substrate cassette 4 and is connected to a load lock chamber 6 and an unload lock chamber 8 of the main body. The chambers constituting the main body are arranged in a star shape, and a transfer mechanism 5 including a transfer robot is disposed at the center. The transport mechanism 5 is connected to each of the peripheral film forming chambers 1 via a gate valve. This film forming apparatus is characterized in that it has a plurality of film forming chambers 1, each of which performs continuous film formation of an oxide film and a semiconductor thin film independently of each other. Therefore, while one of the film forming chambers is being maintained and inspected, the continuous film forming process can be continuously performed in the remaining film forming chambers, so that the processing capacity is improved as a whole.

FIG. 3 is a process chart showing a method for manufacturing a thin film transistor according to the present invention. In this example, the gate nitride film,
In order to continuously form a gate oxide film and a semiconductor thin film, the film forming apparatus shown in FIGS. 1 and 2 is used. Here, a thin film transistor having a bottom gate structure is integrated over a substrate 70. First, as shown in FIG.
A metal is deposited, for example, by sputtering on a substrate 70 having an area of 0 mm × 350 mm and made of, for example, non-alkali glass. Here, Mo.Ta was deposited. The metal deposited by photolithography and etching is patterned and processed into a gate electrode 71. Thereafter, the surface of each gate electrode 71 is anodized to form a Ta oxide film 72.

In step (B), the substrate 70 is loaded into the film forming apparatus according to the present invention. In a film forming chamber, SiN and SiO ₂ are formed by a plasma CVD method (PE-CVD method).
To provide two layers of gate insulating films 73a and 73b.
A semiconductor thin film 74 is provided thereon by depositing amorphous silicon. Here, the gate insulating films 73a and 73b and the semiconductor thin film 74 are continuously grown without breaking the vacuum in the same film forming chamber. Thereafter, the substrate is transferred to the heating chamber. Here, the substrate 70 is heated to, for example, a temperature of 400 ° C. The amorphous silicon semiconductor thin film 74 formed by the PE-CVD method contains about 10% hydrogen,
This hydrogen is desorbed by the heat treatment at ℃. After performing this heat treatment, the substrate 70 is transferred to a laser irradiation device. Here, XeCl excimer laser light 75 having a wavelength of 308 nm is irradiated to crystallize the semiconductor thin film 74. The amorphous silicon is melted by the energy of the laser light and becomes polycrystalline when it hardens. Crystallinity (mainly grain size) is determined by the time at which the solidification occurs. In this example, 15
A single substrate can be processed in about 2 minutes by irradiating a laser beam shaped into a line of 0 mm × 0.4 mm and scanning left and right. After the crystallization process is completed, the substrate 70 is taken out of the laser irradiation device and proceeds to a subsequent step.

As shown in FIG. 1C, SiO ₂ is deposited on the semiconductor thin film 74 by PE-CVD. Here, the SiO ₂ is patterned using the backside exposure technique,
Process into That is, by performing backside exposure using the gate electrode 71 as a mask, the stopper 76 aligned with the gate electrode 71 can be obtained by self-alignment. Here, the semiconductor thin film 74 is doped with, for example, a low-concentration phosphorus dopant 77 by an ion doping method.

Proceeding to step (D), a region of the semiconductor thin film to be an N-channel type thin film transistor is doped with, for example, a high-concentration phosphorus dopant 78. Further, a region of the semiconductor thin film to be a P-channel transistor is doped with a high concentration of boron dopant. A resist 79 is used to separate phosphorus and boron into regions. Usually, impurity ions are implanted in a polycrystalline silicon thin film transistor of a high temperature process by using an ion implantation method. It has a mass separation function and can implant only specific impurity ions. However, in this method, since the ion beam is scanned, a long processing time is required to implant high-concentration impurity ions in a large area, resulting in poor productivity. Therefore, in this embodiment, the impurities are implanted by using the ion doping method. The ion doping method is a method in which ions in a plasma state are rapidly accelerated by an electric field to dope a substrate, and can be processed in a short time. On the other hand, since there is no mass separation, unnecessary atoms may be doped. In addition, the exact number of atoms is not known, which causes variation. Recently, a large-sized ion implantation apparatus that eliminates both disadvantages has been developed, so that improvement in performance is expected.

Proceeding to step (E), laser light is again irradiated to activate the doped atoms. This is the same method as laser crystallization, but weak energy is sufficient because it is not necessary to enlarge the crystal. In general, heat may be applied to activate the glass, but simple heat treatment cannot be used because glass shrinks at 400 ° C. or higher. For example, a method of applying heat only to the semiconductor thin film such as laser irradiation is used.
Incidentally, if hydrogen is simultaneously implanted during ion doping, 30
There is also a report that impurities are activated at a temperature of about 0 ° C. Thereafter, SiO ₂ is deposited for insulation between wirings to form an interlayer insulating film 80.

Proceeding to step (F), after opening a contact hole in the interlayer insulating film 80, for example, metal aluminum is deposited by sputtering and patterned into a predetermined shape to form the wiring 8
Process into 1.

Finally, the process proceeds to step (G), for example, depositing SiN to form a passivation film 82. This passivation film 82 prevents impurities from entering from outside.

FIG. 4 is a graph showing an oxygen concentration profile of a laminated structure formed continuously according to the present invention. The vertical axis indicates the concentration, and the horizontal axis indicates the depth of the laminated structure.
In this laminated structure, a semiconductor thin film made of amorphous silicon, a gate oxide film made of SiO ₂ , and a gate nitride film made of SiN are formed on an insulating substrate made of a silicon wafer in order from the top. The horizontal axis indicates the depth dimension measured from the surface of the uppermost semiconductor thin film. This graph shows the concentrations of Si, N, F, C and H in addition to the concentration of O in the film. As is clear from the graph, the oxygen concentration in the semiconductor thin film was reduced to 10 ²⁰ / by applying a vacuum and a purge between the formation of the gate oxide film and the formation of the semiconductor thin film.
cm ³ . The plasma electrode in the film forming chamber is coated with alumina.

FIG. 5 shows the oxygen concentration in the film when the plasma electrode in the film forming chamber is changed from an alumina coating material to an aluminum material. As is clear from the graph, the oxygen concentration in the semiconductor thin film can be reduced to the order of 10 ¹⁹ / cm ³ .

Finally, an example of an active matrix type display device using a thin film transistor manufactured according to the present invention will be briefly described with reference to FIG. This display device has a panel structure including a driving substrate 101, a counter substrate 102, and an electro-optical material 103 held between the two. As the electro-optical material 103, a liquid crystal material or the like is widely used. The driving substrate 101 can be made of glass which can have a large area and is relatively inexpensive. The pixel array unit 104 and the drive circuit unit are integrated on the drive substrate 101, and a monolithic structure can be adopted.
In other words, the peripheral drive circuit portion can be integrally built in addition to the pixel array portion 104. The drive circuit section is divided into a vertical drive circuit 105 and a horizontal drive circuit 106. or,
A terminal 1 for external connection is provided on the upper end of the peripheral portion of the drive substrate 101.
07 is formed. The terminal portion 107 is connected to a vertical drive circuit 105 and a horizontal drive circuit 106 via a wiring 108. On the other hand, a counter electrode (not shown) is formed entirely on the inner surface of the counter substrate 102. A row-shaped gate line 109 and a column-shaped signal line 110 are formed in the pixel array unit 104. The gate line 109 is connected to the vertical drive circuit 105, and the signal line 110 is connected to the horizontal drive circuit 106. At the intersection of the two lines, a pixel electrode 111 and a thin film transistor 112 for driving the pixel electrode 111 are integrally formed. Further, thin film transistors are also integratedly formed in the vertical drive circuit 105 and the horizontal drive circuit 106. In order to form these thin film transistors, a gate electrode forming step of forming a gate electrode on the insulating substrate 101 and an insulating substrate 101 on which the gate electrode is formed are put into a reaction chamber and a gate oxide film is formed by a chemical vapor deposition method. A continuous film forming step of forming a semiconductor thin film over the gate oxide film in the same reaction chamber; and an implanting step of selectively implanting impurities into the semiconductor thin film to form a source region and a drain region. .

[0024]

As described above, according to the present invention,
In a method of manufacturing a thin film transistor having a bottom gate structure, a gate oxide film and a semiconductor thin film are continuously formed in the same film forming chamber. As a result, the state of the interface between the gate oxide film and the semiconductor thin film can be improved, and the characteristics of the bottom gate thin film transistor can be stabilized.
Further, the productivity of thin film transistors was improved by performing continuous film formation. In particular, by using a plurality of film forming chambers, even when one of the chambers is being maintained and inspected, the remaining film can be continuously formed, so that the processing capacity is increased.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a main part of a continuous film forming apparatus according to the present invention.

FIG. 2 is a perspective view showing an entire configuration of a continuous film forming apparatus according to the present invention.

FIG. 3 is a process chart showing a method for manufacturing a thin film transistor according to the present invention.

FIG. 4 is a graph showing an oxygen concentration profile of a thin film transistor manufactured according to the present invention.

FIG. 5 is a graph showing an oxygen concentration profile of a thin film transistor manufactured according to the present invention.

FIG. 6 is a schematic perspective view showing an example of an active matrix display device using a thin film transistor manufactured according to the present invention.

[Explanation of symbols]

1 ... film forming chamber, 12 ... reaction chamber, 13 ...
Electrode, 14 stage, 15 heater, 16
..Gate valves, 19, high-frequency power supplies, 70,
Insulating substrate, 71: gate electrode, 73a: gate nitride film, 73b: gate oxide film, 74: semiconductor thin film

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/205 H01L 21/28 301R 5F110 21/265 21/31 C 21/28 301 21/316 X 21/31 21 / 265 F 21/316 29/78 613A 616N 617U 617W 627G F-term (reference) 4K030 AA06 AA18 BA29 BA44 BB13 FA03 JA06 KA17 LA15 4M104 AA01 BB16 BB17 CC05 DD37 EE03 EE12 EE16 EE17 FF08 GG17 A08 AC11 AF07 CA15 DP03 EH05 5F052 AA02 BB07 DA02 DB03 JA01 JA10 5F058 BA07 BB07 BC02 BF07 BF23 BF29 BG01 BG02 BG03 BJ04 5F110 AA16 BB02 BB04 CC08 DD02 EE04 EE06 EE44 FF02 FF03 FF13 FF03 FF13 FF03 FF13 FF13 FF13 FF13 FF13 FF13 FF03 FF30 PP04 PP05 PP27 PP35 QQ09 QQ12

Claims (8)

[Claims] A gate electrode forming step of forming a gate electrode on the insulating substrate; placing the insulating substrate on which the gate electrode is formed into a reaction chamber to form a gate oxide film by a chemical vapor deposition method; A thin film transistor comprising: a continuous film forming step of forming a semiconductor thin film on the gate oxide film in the same reaction chamber; and an implanting step of selectively implanting impurities into the semiconductor thin film to form a source region and a drain region. Production method. 2. The continuous film forming step comprises: introducing a first reaction gas containing an oxygen element into a reaction chamber to deposit a gate oxide film by chemical vapor deposition; Exhaust the gas, further flow a second reaction gas containing no oxygen element into the reaction chamber to dilute the remainder of the first reaction gas, and then deposit a semiconductor thin film by chemical vapor deposition using the second reaction gas The method for manufacturing a thin film transistor according to claim 1. 3. The method according to claim 1, wherein the continuous film forming step is performed by using SiH ₄ and N ₂ O.
A gate oxide film made of SiO ₂ is formed using a first reaction gas containing Si, and S 2 is formed using a second reaction gas containing SiH _4.
3. The method according to claim 2, wherein a semiconductor thin film made of i is formed. 4. After forming a gate electrode on an insulating substrate, the gate electrode is put into a reaction chamber to form a gate oxide film by a chemical vapor deposition method, and furthermore, a semiconductor thin film is stacked on the gate oxide film in the same reaction chamber. Wherein the semiconductor thin film has an oxygen concentration controlled to 1 × 10 ²⁰ / cm ³ or less. 5. The thin film transistor according to claim 4, wherein a trap density at an interface between the gate oxide film and the semiconductor thin film is controlled to 3 × 10 ¹¹ / cm ² or less. 6. A continuous film forming apparatus comprising a reaction chamber capable of evacuating, an electrode for applying a high frequency, and a stage for mounting a substrate to be processed, wherein the first reaction gas containing an oxygen element is provided. Is introduced into the reaction chamber and an oxide film is deposited while applying a high frequency. Then, a second reaction gas containing no oxygen element is introduced into the same reaction chamber to deposit a semiconductor thin film. A continuous film forming apparatus characterized in that the material of the film is non-adsorbent to the first reaction gas. 7. The continuous film forming apparatus according to claim 6, wherein a plurality of reaction chambers are provided, each of which performs a continuous film formation of an oxide film and a semiconductor thin film independently of each other. 8. A pixel electrode and a thin film transistor for driving the pixel electrode are formed on a pair of insulating substrates joined to each other via a predetermined gap and an electro-optical material held in the gap. A method for manufacturing a display device, wherein a counter electrode is formed on the other insulating substrate, wherein a gate electrode forming step of forming a gate electrode on the one insulating substrate to form the thin film transistor; A continuous film forming step of placing the insulating substrate with the gate electrode formed therein in a reaction chamber, forming a gate oxide film by chemical vapor deposition, and further forming a semiconductor thin film on the gate oxide film in the same reaction chamber; Performing a step of forming a source region and a drain region by selectively injecting impurities into the semiconductor thin film.