Method for forming carbon-containing film

Abstract

A method for forming a carbon-containing film, according to an embodiment of the present invention, may comprise the steps of: spraying, into a chamber in which a substrate is accommodated, a carbon-containing gas so as to form an amorphous film on the substrate; and forming plasma while spraying a nitrogen-containing gas into the chamber, so as to crystallize the amorphous film while doping the amorphous film with nitrogen. Therefore, according to embodiments of the present invention, a crystalline carbon-containing film can be easily formed at a low temperature. Thus, when the crystalline carbon-containing film is formed, damage, caused by high-temperature heat, to a substrate and / or a lower film can be suppressed or prevented.

Description

Method for forming a carbon-containing film

[0001] The present invention relates to a method for forming a carbon-containing film, and more specifically, to a method for forming a carbon-containing film capable of forming a crystalline carbon-containing film at a low temperature.

[0002] Generally, a crystalline carbon-containing film (hereinafter referred to as a graphene film) is formed using a transfer process. To explain this, first, a catalytic metal film is deposited on a copper (Cu) substrate, and graphene is synthesized on the catalytic metal film. Thus, a graphene film is formed on the catalytic metal film. However, in order to apply the graphene film to a desired device, the graphene film must be separated from the catalytic metal film and transferred onto a PMMA (Poly(methyl methacrylate) film. However, during the transfer process, the graphene film may be contaminated by organic materials contained in the PMMA film, and damage such as tearing or folding may occur during the transfer process.

[0003] To solve the problems caused by such transfer processes, a graphene film is formed using a method that omits the transfer process. To explain this, a catalytic metal film is first formed on a substrate using a deposition method. Then, after patterning the catalytic metal film, graphene is synthesized, and a graphene film is formed on the catalytic metal film. However, graphene synthesis is carried out at high temperatures of 900°C to 1000°C. Consequently, there is a problem in that the underlying film of the graphene film or the substrate is damaged by the high heat. In addition, there is a limitation that only a silicon substrate (e.g., a Si wafer) can be used as the substrate to reduce damage caused by high heat during graphene synthesis.

[0004] (Prior Art) (Patent Document 1) Korean Registered Patent 10-2567982

[0005] The present invention provides a method for forming a carbon-containing film capable of forming a crystalline carbon-containing film at low temperatures.

[0006] The present invention provides a method for forming a carbon-containing film that can suppress or prevent damage to one or more of a substrate and a subfilm by high heat.

[0007] An embodiment of the present invention is a method for forming a carbon-containing film inside a chamber in which a substrate is accommodated, comprising the steps of: injecting a carbon-containing gas into the interior of the chamber; and forming a direct plasma inside the chamber.

[0008] The step of forming the direct plasma above can form the plasma using a nitrogen-containing gas.

[0009] The step of forming the direct plasma above may further utilize a gas comprising one or more of argon (Ar), helium (He), and hydrogen (H) to form the plasma.

[0010] An embodiment of the present invention is a method for forming a carbon-containing film inside a chamber in which a substrate is accommodated, comprising the steps of: injecting a carbon-containing gas into the interior of the chamber; forming a direct plasma inside the chamber using a gas containing one or more of argon (Ar), helium (He), and hydrogen (H); and forming a direct plasma inside the chamber using a nitrogen-containing gas.

[0011] An embodiment of the present invention is a method for forming a carbon-containing film inside a chamber in which a substrate is accommodated, comprising the steps of: injecting a carbon-containing gas into the interior of the chamber; forming a direct plasma using a nitrogen-containing gas inside the chamber; and forming a direct plasma using a gas containing one or more of argon (Ar), helium (He), and hydrogen (H) inside the chamber.

[0012] According to embodiments of the present invention, a crystalline carbon-containing film can be easily formed at a low temperature. Accordingly, when forming a crystalline carbon-containing film, damage to one or more of the substrate and the underlying film by high-temperature heat can be suppressed or prevented.

[0013] In addition, it can fill defects formed in the crystalline carbon-containing film. Therefore, it has the effect of improving the properties of the carbon-containing film. Furthermore, in crystallizing the carbon-containing film, it can facilitate nucleation and improve the growth rate.

[0014] FIG. 1 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the first embodiment of the present invention.

[0015] Figures 2(a) and 2(b) are conceptual process diagrams illustrating a method for forming a carbon-containing film on a substrate according to the first embodiment of the present invention.

[0016] FIG. 3 is a conceptual diagram illustrating a method for forming a carbon-containing film according to the first embodiment of the present invention.

[0017] Figures 4 (a) to (c) are conceptual process diagrams illustrating a method of forming a carbon-containing film on a substrate according to a second embodiment of the present invention.

[0018] FIG. 5 is a conceptual diagram illustrating a method for forming a carbon-containing film according to a second embodiment of the present invention.

[0019] FIG. 6 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the third embodiment of the present invention.

[0020] FIGS. 7 (a) to (d) is a conceptual process diagram illustrating a method for forming a carbon-containing film on a substrate according to the third embodiment of the present invention.

[0021] FIG. 8 is a conceptual diagram illustrating a method for forming a carbon-containing film according to the third embodiment of the present invention.

[0022] FIG. 9 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the fourth embodiment of the present invention.

[0023] FIG. 10 is a conceptual diagram illustrating a method for forming a carbon-containing film according to the fourth embodiment of the present invention.

[0024] Figure 11 is a diagram showing a thin-film transistor.

[0025] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms; these embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. The drawings may be exaggerated to illustrate the embodiments of the present invention.

[0026]

[0027] FIG. 1 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the first embodiment of the present invention.

[0028] A carbon-containing film (20) can be formed on a substrate (10). The substrate (10) may be either glass or a wafer. The wafer may be any one of a glass wafer, a silicon wafer (Si wafer), a silicon oxide wafer (SiO wafer), or a silicon nitride wafer (SiN wafer). Here, the silicon oxide wafer (SiO wafer) may be a silicon wafer having a silicon oxide film formed on at least one surface, and the silicon nitride wafer (SiN wafer) may be a silicon wafer having a silicon nitride film formed on at least one surface.

[0029] The carbon-containing film (20) may be a film containing carbon (C) and nitrogen (N), and may be a crystalline film. That is, the carbon-containing film (20) may be a graphene film doped with nitrogen (N).

[0030] The carbon-containing film (20) described above can be used, for example, as a channel layer of a thin-film transistor. The configuration of the thin-film transistor will be explained again later.

[0031]

[0032] FIGS. 2(a) and (b) are process diagrams conceptually illustrating a method of forming a carbon-containing film on a substrate according to the first embodiment of the present invention. FIG. 3 is a conceptual diagram for explaining a method of forming a carbon-containing film according to the first embodiment of the present invention.

[0033] In Fig. 3, 'on' may mean spraying raw materials for forming a carbon-containing film or generating plasma, and 'off' may mean stopping or terminating the spraying of raw materials or not generating plasma.

[0034] The carbon-containing film (20) according to the embodiments of the present invention may be a crystalline film or a graphene film doped with nitrogen (N) as described above. In forming such a carbon-containing film (20), a deposition device capable of forming plasma inside a chamber may be used. That is, the carbon-containing film (20) may be formed using a deposition device capable of forming direct plasma.

[0035] A deposition apparatus for forming a carbon-containing film (20) according to embodiments of the present invention will be briefly described below.

[0036] A deposition apparatus may include a chamber having an internal space, a support member installed inside the chamber to support a substrate (10), a gas injection member disposed inside the chamber to spray raw materials for forming a carbon-containing film (20) toward the support member, and a power supply member capable of supplying power to at least one of the gas injection member and the support member. Additionally, the deposition apparatus may include a heater installed in at least one of the chamber and the support member to heat at least one of the internal space of the chamber and the substrate. In such a deposition apparatus, the support member and the gas injection member act as electrodes, and the power supply member can supply RF (Radio Frequency) power to at least one of the support member and the gas injection member. Accordingly, plasma can be formed inside the chamber due to the potential difference between the support member and the gas injection member. That is, plasma can be formed directly inside the chamber.

[0037] Referring to FIGS. 2(a) and (b) and FIG. 3, a method for forming a carbon-containing film (20) may include the step of forming an amorphous film (21) on a substrate (10) by injecting a gas containing carbon (C) (hereinafter, carbon-containing gas) into the interior of a chamber, and the step of crystallizing the amorphous film (21) by forming a plasma inside the chamber while injecting a gas containing nitrogen (hereinafter, nitrogen-containing gas) into the interior of the chamber.

[0038] In the following description of the first embodiment, the step of forming an amorphous film (21) on a substrate (10) by injecting a carbon-containing gas is briefly referred to as the "carbon-containing gas injection step." Additionally, the step of crystallizing the amorphous film (21) by forming a plasma inside the chamber while injecting a nitrogen-containing gas (hereinafter, nitrogen-containing gas) into the chamber is briefly referred to as the "plasma formation step." Furthermore, the step of crystallizing the amorphous film (21) by forming a plasma inside the chamber while injecting a nitrogen-containing gas (hereinafter, nitrogen-containing gas) into the chamber may also be referred to as the "crystallization step."

[0039] Referring to FIG. 3, the 'carbon-containing gas injection step - plasma formation step (or crystallization step)' can be made into a single process cycle (CY). Here, the plasma formation step (or crystallization step) may include a step of injecting a nitrogen-containing gas and a step of injecting a discharge gas.

[0040] Additionally, the method for forming the carbon-containing film (20) may include a 'first purging step' in which purge gas is injected into the interior of the chamber between the 'carbon-containing gas injection step' and the 'plasma formation step' to purge the interior of the chamber. If the method for forming the carbon-containing film (20) includes a purging step, the 'carbon-containing gas injection step - first purging step - plasma formation step' can be made into a single process cycle (CY).

[0041] Additionally, although not explicitly described, a second purging step may be included to purge the chamber by injecting purge gas into the interior of the chamber after the plasma formation step is completed. Accordingly, the 'carbon-containing gas injection step - purging step (first purging step) - plasma formation step - purging step (second purging step)' can be considered as a single process cycle (CY).

[0042] The process cycle (CY) described above can be performed n times (n: 1, 2, 3, …). That is, the method of forming the carbon-containing film (20) may include one process cycle (CY) (n=1) or two or more process cycles (CY) (n ≥ 2). Here, two or more times may mean multiple times.

[0043]

[0044] Hereinafter, a method for forming a carbon-containing film (20) according to the first embodiment will be described in more detail with reference to FIG. 2 (a) and (b) and FIG. 3.

[0045] First, a substrate (10) is placed inside the chamber and supported on a support member. Then, at least one of the chamber and the substrate (10) is heated using a heater. At this time, the temperature of at least one of the chamber and the substrate (10) is heated to 100°C to 700°C (100°C or higher and 700°C or lower). Then, during the process, the temperature of at least one of the chamber and the substrate (10) is maintained at 100°C to 700°C. To explain with a more specific example, the temperature of at least one of the chamber and the substrate (10) can be maintained at any one of the following: 100°C to 200°C, 200°C to 300°C, 300°C to 400°C, 400°C to 500°C, 500°C to 600°C, and 600°C to 700°C.

[0046] Next, a carbon-containing gas is injected into the interior of the chamber using a gas injection unit. The carbon-containing gas may be a gas containing at least one of methane (CH4), methyl glycerin (CH3), and acetylene (C2H2). Of course, in addition to methane (CH4), methyl glycerin (CH3), and acetylene (C2H2), various gases containing carbon (C) may be used as the carbon-containing gas. When the carbon-containing gas is injected into the interior of the chamber, a carbon-containing film may be adsorbed or deposited on the substrate (10). At this time, the film deposited on the substrate (10) may be an amorphous film (21) containing carbon.

[0047] When the step of injecting carbon-containing gas is completed, purge gas is injected into the interior of the chamber using a gas injection unit, and an exhaust unit is operated. Accordingly, the interior of the chamber can be purged (first purge step). The purge gas may be, for example, argon (Ar) gas.

[0048] When the first purging step is completed, a plasma is formed by injecting a nitrogen-containing gas into the chamber. At this time, additional discharge gas may be injected into the chamber to facilitate the formation of the plasma. The nitrogen-containing gas may be, for example, N2 gas. Of course, the nitrogen-containing gas is not limited to N2 gas, and various gases containing nitrogen (N) may be used. The discharge gas may be a gas containing one or more of argon (Ar), helium (He), and hydrogen (H). That is, the discharge gas may contain one or more of argon (Ar), helium (He), and hydrogen (H) gases.

[0049] In addition, while injecting nitrogen-containing gas and discharge gas into the interior of the chamber, RF power or RF power is applied to at least one of the gas injection unit and the support unit using a power supply unit. Accordingly, as at least one of the nitrogen-containing gas and the discharge gas is discharged, plasma can be formed inside the chamber. That is, direct plasma can be formed inside the chamber due to the potential difference between the support unit and the gas injection unit.

[0050] Nitrogen contained in the nitrogen-containing gas can be doped into an amorphous film (21). Then, when plasma is formed inside the chamber, the amorphous film (21) can be exposed to the plasma. At this time, the amorphous film (21) can be crystallized by the energy of the plasma. Accordingly, a crystalline carbon-containing film (20) doped with nitrogen (N) can be formed. That is, a graphene film doped with nitrogen (N) can be formed.

[0051] In addition, a carbon-containing film (20) can be formed by performing a process cycle (CY) including a 'carbon-containing gas injection step, a purge step, and a plasma formation step' one or two or more times. That is, a carbon-containing film (20) that is crystalline or graphene film can be formed. At this time, the process cycle can be performed one or two or more times to achieve a target thickness. In addition, if the process cycle (CY) is performed two or more times, a multi-layer carbon-containing film (20) can be formed.

[0052] As described above, a plasma is formed inside the chamber to crystallize the amorphous film. Accordingly, the crystallization step may include the step of forming plasma inside the chamber. That is, the crystallization step may include the step of forming plasma inside the chamber.

[0053] Additionally, when forming a plasma to crystallize the amorphous film (21), nitrogen is doped by injecting a nitrogen-containing gas into the interior of the chamber. Accordingly, the crystallization step may include a nitrogen-containing gas injection step or a nitrogen doping step. That is, the crystallization step may include a step of forming a plasma and a nitrogen-containing gas injection step (or nitrogen doping step).

[0054] In the above description, it was explained that forming plasma by injecting a carbon-containing gas followed by injecting a nitrogen-containing gas constitutes a single process cycle (CY). However, the process cycle (CY) is not limited thereto and may further include a step of forming plasma using a discharge gas after performing the step of forming plasma by injecting a nitrogen-containing gas. Furthermore, when forming plasma using a discharge gas after the step of forming plasma by injecting a nitrogen-containing gas is completed, the nitrogen-containing gas may not be injected.

[0055]

[0056] Conventionally, in order to form a crystalline carbon-containing film (20), the temperature of the chamber and the substrate (10) was heated to a high temperature exceeding 700°C. More specifically, it was heated to a temperature of 900°C to 1000°C. In this case, there is a problem that the lower film formed on the lower part of the carbon-containing film (20) is damaged.

[0057] However, in the embodiments, a plasma can be formed to crystallize the amorphous film (21). That is, if a plasma is formed after the amorphous film (21) is formed, the amorphous film (21) can be crystallized by the energy of the plasma. In other words, by forming a plasma, a crystalline carbon-containing film (20) can be formed even at a low temperature of 100°C to 700°C. Accordingly, damage to at least one of the substrate (20) and the lower film due to high heat can be suppressed or prevented.

[0058] Additionally, a crystalline carbon-containing film (or graphene film) (20) can be directly formed or grown on the substrate (10). Furthermore, after forming the crystalline carbon-containing film (20), there is no need to transfer the carbon-containing film (20) to another substrate or film. Therefore, damage to the carbon-containing film (20) caused by the transfer process can be prevented.

[0059] In addition, by doping nitrogen into the carbon-containing film (20), the radical density of the carbon-containing film (20) can be increased. Accordingly, nucleation for the formation of a crystalline carbon-containing film (i.e., a graphene film) is facilitated, and growth in the vertical direction can be promoted.

[0060]

[0061] FIGS. 4(a) to (c) are process diagrams conceptually illustrating a method of forming a carbon-containing film on a substrate according to a second embodiment of the present invention. FIG. 5 is a conceptual diagram for explaining a method of forming a carbon-containing film according to a second embodiment of the present invention.

[0062] In Fig. 5, 'on' may mean spraying raw materials for forming a carbon-containing film or generating plasma, and 'off' may mean stopping or terminating the spraying of raw materials or not generating plasma.

[0063]

[0064] Referring to FIG. 4 (a) to (c), the method for forming a carbon-containing film (20) according to the second embodiment may include the steps of forming an amorphous film (21) on a substrate (10) by injecting a carbon-containing gas into the interior of a chamber, forming a crystalline carbon-containing film (20) by forming a plasma inside the chamber to crystallize the amorphous film (21), and doping nitrogen into the carbon-containing film (20) by injecting a nitrogen-containing gas into the interior of the chamber.

[0065] In the following description of the second embodiment, the step of "forming an amorphous film (21) on a substrate (10) by injecting a carbon-containing gas" is referred to as the "carbon-containing gas injection step." Additionally, the step of "forming a plasma inside a chamber to crystallize the amorphous film (21) and form a crystalline carbon-containing film (20)" is briefly referred to as the "plasma formation step." Furthermore, the step of "forming a plasma inside a chamber to crystallize the amorphous film (21)" may also be referred to as the "crystallization step."

[0066] Additionally, the step of ‘injecting nitrogen-containing gas into the interior of the chamber to dope nitrogen into the carbon-containing membrane (20)’ may be named the ‘nitrogen-containing gas injection step’ or the ‘nitrogen doping step’.

[0067] Referring to FIG. 5, the 'carbon-containing gas injection step - plasma formation step (crystallization step) - nitrogen-containing gas injection step (nitrogen doping step)' can be made into a single process cycle (CY). Here, the plasma formation step (crystallization step) may include a step of injecting discharge gas into the interior of a chamber.

[0068] Additionally, the method for forming the carbon-containing film (20) may include a "first purging step" performed between the "carbon-containing gas injection step" and the "plasma formation step." Accordingly, the "carbon-containing gas injection step - first purging step - plasma formation step - nitrogen-containing gas injection step" can be made into a single process cycle (CY).

[0069] Additionally, although not explicitly stated, a second purging step for purging the interior of the chamber after the nitrogen-containing gas injection step (nitrogen doping step) is completed may be further included. Accordingly, the 'carbon-containing gas injection step - first purging step - plasma formation step - nitrogen-containing gas injection step - second purging step' can be made into a single process cycle (CY).

[0070] The plasma formation step may include the step of injecting a discharge gas into the interior of a chamber and the step of applying RF power to at least one of the gas injection unit and the support unit using a power supply unit. In addition, the discharge gas may include one or more of argon (Ar), helium (He), and hydrogen (H) gases.

[0071] In addition, plasma can be formed inside the chamber when a nitrogen-containing gas is injected. That is, while injecting a nitrogen-containing gas into the chamber, RF power can be applied to at least one of the gas injection unit and the support unit using a power supply unit. Accordingly, the nitrogen-containing gas can be discharged inside the chamber, and as a result, plasma can be formed inside the chamber.

[0072] In this way, when nitrogen plasma is formed inside the chamber, nitrogen can be more easily introduced into the carbon-containing film (20). In other words, nitrogen doping can be made smoother by the nitrogen plasma.

[0073] After the carbon-containing gas injection and purging steps are completed, if a plasma is formed inside the chamber, the amorphous film (21) can be exposed to the plasma. Accordingly, the amorphous film (21) can be crystallized by the energy of the plasma. As a result, a crystalline carbon-containing film (20) can be formed. That is, a graphene film can be formed. In addition, nitrogen can be doped into the carbon-containing film (20) by injecting a nitrogen-containing gas after the plasma formation step is completed. Thus, the carbon-containing film (20) can be a nitrogen-doped crystalline film or a graphene film.

[0074] In addition, an amorphous film can be crystallized using plasma. Accordingly, a crystalline carbon-containing film (20) can be formed even if the temperature of at least one of the interior of the chamber, the support, and the substrate is maintained at a low temperature of 100°C to 700°C. Accordingly, damage to at least one of the substrate (10) and the lower film of the carbon-containing film (20) due to high heat can be suppressed or prevented.

[0075] In addition, as described above, by doping with nitrogen, the radical density of the carbon-containing film (20) can be increased. Accordingly, nucleation for the formation of a crystalline carbon-containing film (i.e., a graphene film) is facilitated, and growth in the vertical direction can be promoted.

[0076] A carbon-containing film (20) can be formed by performing a process cycle (CY) including the 'carbon-containing gas injection step, purge step, plasma formation step, and nitrogen-containing gas injection step' as described above one or two or more times. That is, a carbon-containing film (20) that is crystalline or graphene film can be formed. At this time, the process cycle can be performed one or two or more times to achieve a target thickness. And, a multi-layer carbon-containing film (20) can be formed by performing the process cycle (CY) two or more times.

[0077]

[0078] FIG. 6 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the third embodiment of the present invention. FIG. 7 (a) to (d) are process diagrams conceptually illustrating a method of forming a carbon-containing film on a substrate by a method according to the third embodiment of the present invention. FIG. 8 is a conceptual diagram for explaining a method of forming a carbon-containing film by a method according to the third embodiment of the present invention.

[0079] In Fig. 8, 'on' means to spray raw materials for forming a carbon-containing film or to generate plasma, and 'off' may mean to stop or terminate the spraying of raw materials or not to generate plasma.

[0080] In the first and second embodiments described above, it was explained that an amorphous film (21) is crystallized to form a crystalline carbon-containing film (20). However, this is not limited thereto, and as in the third embodiment shown in FIG. 6, an amorphous first carbon-containing film (21a) and a crystalline second carbon-containing film (21b) can be formed alternately. That is, the carbon-containing film (20) according to the third embodiment may include an amorphous first carbon-containing film (21a) and a crystalline second carbon-containing film (21b) formed on the first carbon-containing film (21a). Also, the second carbon-containing film (21b) may be a graphene film.

[0081] As described above, the carbon-containing film (20) according to the third embodiment includes a first carbon-containing film (21a) that is doped with nitrogen. Accordingly, the carbon-containing film (20) including the first and second carbon-containing films (21a, 21b) may be a nitrogen-doped film.

[0082] A first carbon-containing film (21a) and a second carbon-containing film (21b) may be formed alternately. Additionally, the first carbon-containing film (21a) may be formed in two or more numbers, and the second carbon-containing film (21b) may be formed in one or more numbers. Furthermore, the number of amorphous first carbon-containing films (21a) may be greater than the number of crystalline second carbon-containing films (21b). For example, the number of first carbon-containing films (21a) may be one or more greater than the number of second carbon-containing films (21b). Also, the first film formed on the substrate (10) and the last film formed may be the first carbon-containing film (21a).

[0083] Referring to FIGS. 7(a) to (d), the method may include the step of forming an amorphous first carbon-containing film (21a) on a substrate (10) by injecting a carbon-containing gas into the chamber (Fig. 7(a)), the step of doping nitrogen (N) into the first carbon-containing film (21a) by injecting a nitrogen-containing gas into the chamber (Fig. 7(b)), the step of forming an amorphous second carbon-containing film (21b) on the first carbon-containing film (21a) by injecting a carbon-containing gas into the chamber (Fig. 7(c)), and the step of crystallizing the second carbon-containing film (21b) by forming a plasma inside the chamber (Fig. 7(d)).

[0084] In the following description of the third embodiment, the step of "forming an amorphous first carbon-containing film (21a) on a substrate (10) by spraying a carbon-containing gas" is briefly referred to as the "first carbon-containing gas spraying step," and the step of "forming an amorphous second carbon-containing film (21b) on the first carbon-containing film (21a) by spraying a carbon-containing gas" is briefly referred to as the "second carbon-containing gas spraying step." Additionally, the step of "forming an amorphous first carbon-containing film (21a) on a substrate (10) by spraying a carbon-containing gas" may be briefly referred to as the "first carbon-containing film formation step," and the step of "forming an amorphous second carbon-containing film (21b) on the first carbon-containing film (21a) by spraying a carbon-containing gas" may be briefly referred to as the "second carbon-containing film formation step."

[0085] Additionally, the 'step of doping nitrogen (N) into the first carbon-containing film (21a) by injecting a nitrogen-containing gas' may be referred to as the 'nitrogen-containing gas injection step' or the 'nitrogen doping step'. Furthermore, the 'step of crystallizing the second carbon-containing film (21b) by forming a plasma inside the chamber' may be briefly referred to as the 'plasma formation step'. Additionally, the 'step of crystallizing the second carbon-containing film (21b) by forming a plasma inside the chamber' may be briefly referred to as the 'crystallization step'.

[0086]

[0087] Hereinafter, a method for forming a carbon-containing film according to the third embodiment will be described with reference to FIGS. 6, FIGS. 7 (a) to (d), and FIG. 8.

[0088] Referring to FIG. 8, the method for forming a carbon-containing film (20) according to the third embodiment may include a first process cycle (CY1) and a second process cycle (CY2).

[0089] The first process cycle (CY1) may include a first carbon-containing gas injection step and a nitrogen-containing gas injection step (nitrogen doping step). Additionally, the first process cycle (CY1) may be a process carried out in the order of 'first carbon-containing gas injection step - nitrogen-containing gas injection step (nitrogen doping step)'. Furthermore, the second process cycle (CY2) may include a second carbon-containing gas injection step and a plasma formation step (crystallization step). Additionally, the second process cycle (CY2) may be a process carried out in the order of 'second carbon-containing gas injection step - plasma formation step (crystallization step)'. Here, the plasma formation step (crystallization step) may include a step of injecting discharge gas into the interior of a chamber.

[0090] The first process cycle (CY1) may include a purging step (first purging step) performed between the first carbon-containing gas injection step and the nitrogen-containing gas injection step, and the second process cycle (CY2) may include a purging step (second purging step) performed between the second carbon-containing gas injection step and the plasma formation step. Accordingly, the first process cycle (CY1) may be performed in the order of 'first carbon-containing gas injection step - first purging step - nitrogen-containing gas injection step (nitrogen doping step)'. Additionally, the second process cycle (CY2) may be performed in the order of 'second carbon-containing gas injection step - second purging step - plasma formation step (crystallization step)'. Furthermore, the second process cycle (CY2) may further include a 'third purging step' that purifies the interior of the chamber by injecting purging gas into the chamber after the plasma formation step (crystallization step) is completed. Accordingly, the second process cycle (CY2) can be carried out in the order of 'second carbon-containing gas injection step - second purging step - plasma formation step (crystallization step) - third purging step'.

[0091] The carbon-containing gas injected in the first carbon-containing gas injection step and the second carbon-containing gas injection step may be a gas comprising at least one of methane (CH4), methyl glycerin (CH3), and acetylene (C2H2). Additionally, the carbon-containing gas injected in the first carbon-containing gas injection step and the second carbon-containing gas injection step may be the same or different from each other.

[0092] Additionally, the plasma forming step may include the step of injecting a discharge gas into the interior of a chamber and the step of applying RF power to at least one of the gas injection unit and the support unit using a power supply unit. And, the discharge gas may include one or more of argon (Ar), helium (He), and hydrogen (H) gases.

[0093] When injecting a nitrogen-containing gas, plasma can be formed inside the chamber. That is, while injecting a nitrogen-containing gas into the chamber, RF power can be applied to at least one of the gas injection unit and the support unit using a power supply. Accordingly, the nitrogen-containing gas can be discharged inside the chamber, and as a result, plasma can be formed inside the chamber. In this way, when nitrogen plasma is formed inside the chamber, nitrogen can be more easily introduced into the first carbon-containing film (21a).

[0094] The first process cycle (CY1) and the second process cycle (CY2) can be performed alternately. Additionally, the number of times the first process cycle (CY1) is performed may be greater than the number of times the second process cycle (CY2) is performed. That is, the first process cycle (CY1) can be performed two or more times, and the second process cycle (CY2) can be performed once or one or more times, and the first process cycle (CY1) can be performed one or more times more than the second process cycle (CY2).

[0095] When the first process cycle (CY1) is performed, an amorphous, nitrogen-doped first carbon-containing film (21a) is formed on the substrate (10). Subsequently, by performing the second process cycle (CY2), a crystalline second carbon-containing film (21b) is formed on the first carbon-containing film (21a). Next, the first process cycle (CY1) is performed again to form an amorphous first carbon-containing film (21a) on the crystalline second carbon-containing film (21b).

[0096] Meanwhile, after forming the first carbon-containing film (21a), when performing the second process cycle (CY2) to form a crystalline second carbon-containing film (21b), defects such as holes or gaps may occur in the second carbon-containing film (21b). That is, when forming a plasma and exposing the second carbon-containing film (21b) to the plasma to crystallize the second carbon-containing film (21b), defects such as holes or gaps may occur in the second carbon-containing film (21b) due to the energy of the plasma. And such defects may degrade the characteristics of the carbon-containing film (20), for example, electrical characteristics.

[0097] However, in the embodiment, after forming the second carbon-containing film (21b), an amorphous first carbon-containing film (21a) is formed on the second carbon-containing film (21b). That is, the first process cycle (CY1) and the second process cycle (CY2) are carried out alternately, and the first process cycle (CY2) is carried out at least one more time than the second process cycle (CY2) to form an amorphous first carbon-containing film (21a) on the second carbon-containing film (21b).

[0098] When an amorphous first carbon-containing film (21a) is formed on a second carbon-containing film (21b), holes or gaps contained in the second carbon-containing film (21b) can be filled by the first carbon-containing film (21a). Accordingly, the characteristics of the carbon-containing film (20), for example, electrical characteristics, can be improved.

[0099] In addition, the second carbon-containing film (21b) can be crystallized by forming a plasma after injecting the second carbon-containing gas. That is, by forming a plasma, a crystalline second carbon-containing film (21b) can be formed at a low temperature of 100°C to 700°C. Accordingly, damage to at least one of the second carbon-containing film (21b), the lower film of the carbon-containing film (20), and the substrate (10) due to high heat can be suppressed or prevented.

[0100] Then, a crystalline second carbon-containing film (21b) is formed on a first carbon-containing film (21a) doped with nitrogen. Here, the first carbon-containing film (21a) may have a high radical density due to nitrogen. Therefore, when crystallizing the second carbon-containing film (21b) on the first carbon-containing film (21a), nucleation of the second carbon-containing film (21b) may be facilitated, and growth in the vertical direction may be promoted.

[0101]

[0102] FIG. 9 is a diagram illustrating a state in which a carbon-containing film is formed on a substrate by a method according to the fourth embodiment of the present invention. FIG. 10 is a conceptual diagram for explaining a method of forming a carbon-containing film by a method according to the fourth embodiment of the present invention.

[0103] In Fig. 10, 'on' means to spray raw materials for forming a carbon-containing film or to generate plasma, and 'off' may mean to stop or terminate the spraying of raw materials or not to generate plasma.

[0104] In the third embodiment described above, it was explained that the first carbon-containing film (21a) is a nitrogen-doped amorphous film and the second carbon-containing film (21b) is a crystalline film. Additionally, in the third embodiment, the first carbon-containing film (21a), which is an amorphous film, was first formed on the substrate (10), and then the second carbon-containing film (21b) was formed on the first carbon-containing film (21a).

[0105] However, not limited to this, the first carbon-containing film (21a) formed first on the substrate (10) can be formed as a crystalline film, and the second carbon-containing film (21b) formed on the first carbon-containing film (21a) can be formed as an amorphous film.

[0106] Referring to FIG. 9, the carbon-containing film (20) according to the fourth embodiment may include a first carbon-containing film (21a) which is crystalline and a second carbon-containing film (21b) which is amorphous and formed on the first carbon-containing film (21a). The first carbon-containing film (21a) may be a graphene film, and the second carbon-containing film (21b) may be a nitrogen-doped film.

[0107] A first carbon-containing film (21a) and a second carbon-containing film (21b) may be formed alternately. Additionally, each of the first and second carbon-containing films (21a, 21b) may be formed as one or more. Furthermore, the first film formed on the substrate (10) may be a crystalline film, the first carbon-containing film (21a), and the last film formed may be an amorphous film, the second carbon-containing film (21b).

[0108]

[0109] Hereinafter, a method for forming a carbon-containing film according to the fourth embodiment will be described with reference to FIGS. 9 and FIGS. 10.

[0110] Referring to FIG. 10, the method for forming a carbon-containing film (20) according to the fourth embodiment may include a first process cycle (CY1) and a second process cycle (CY2).

[0111] The first process cycle (CY1) may include a first carbon-containing gas injection step and a plasma formation step (crystallization step). Additionally, the first process cycle (CY1) may be a process carried out in the order of 'first carbon-containing gas injection step - plasma formation step (crystallization step)'. Here, the plasma formation step (crystallization step) may include a discharge gas injection step. Furthermore, the second process cycle (CY2) may include a second carbon-containing gas injection step and a nitrogen-containing gas injection step (nitrogen doping step). Additionally, the second process cycle (CY2) may be a process carried out in the order of 'second carbon-containing gas injection step - nitrogen-containing gas injection step (nitrogen doping step)'.

[0112] The first process cycle (CY1) may include a purging step (first purging step) performed between the first carbon-containing gas injection step and the plasma formation step, and the second process cycle (CY2) may include a purging step (second purging step) performed between the second carbon-containing gas injection step and the nitrogen-containing gas injection step. Accordingly, the first process cycle (CY1) may be performed in the order of 'first carbon-containing gas injection step - first purging step - plasma formation step (crystallization step)'. Additionally, the second process cycle (CY2) may be performed in the order of 'second carbon-containing gas injection step - second purging step - nitrogen-containing gas injection step (nitrogen doping step)'.

[0113] In addition, the second process cycle (CY2) may further include a 'third purging step' in which purge gas is injected into the interior of the chamber to purge the interior of the chamber after the nitrogen-containing gas injection step (nitrogen doping step) is completed. Accordingly, the second process cycle (CY2) may be carried out in the order of 'second carbon-containing gas injection step - second purging step - nitrogen-containing gas injection step (nitrogen doping step) - third purging step'.

[0114] The first process cycle (CY1) and the second process cycle (CY2) can be performed alternately. Additionally, the number of times the first process cycle (CY1) is performed and the number of times the second process cycle (CY2) is performed may be the same or different.

[0115] The carbon-containing gas injected in the first carbon-containing gas injection step and the second carbon-containing gas injection step may be a gas comprising at least one of methane (CH4), methyl glycerin (CH3), and acetylene (C2H2). Additionally, the carbon-containing gas injected in the first carbon-containing gas injection step and the second carbon-containing gas injection step may be the same or different from each other.

[0116] Additionally, the plasma forming step may include the step of injecting a discharge gas into the interior of a chamber and the step of applying RF power to at least one of the gas injection unit and the support unit using a power supply unit. And, the discharge gas may include one or more of argon (Ar), helium (He), and hydrogen (H) gases.

[0117] In addition, plasma can be formed inside the chamber when nitrogen-containing gas is injected. That is, while injecting nitrogen-containing gas into the chamber, RF power can be applied to at least one of the gas injection unit and the support unit using a power supply unit. Accordingly, nitrogen-containing gas can be discharged inside the chamber, and as a result, plasma can be formed inside the chamber. In this way, when nitrogen plasma is formed inside the chamber, nitrogen can be more easily introduced into the first carbon-containing film (21a).

[0118] When a first carbon-containing gas is sprayed onto a substrate (10), an amorphous first carbon-containing film (21a) is formed on the substrate (10). Subsequently, when plasma is formed inside a chamber, the first carbon-containing film (21a) can be exposed to the plasma. Accordingly, the first carbon-containing film (21a) can crystallize to form a crystalline film or a graphene film. However, when the first carbon-containing film (21a) crystallizes, defects such as holes or gaps may occur in the first carbon-containing film (21a) due to the energy of the plasma. And such defects can degrade the characteristics of the carbon-containing film (20), for example, electrical characteristics.

[0119] In the embodiment, after forming a first carbon-containing film (21a), an amorphous second carbon-containing film (21b) is formed on the first carbon-containing film (21a). That is, a first process cycle (CY1) and a second process cycle (CY2) are alternately performed to form an amorphous second carbon-containing film (21b) on the first carbon-containing film (21a). Accordingly, when the amorphous second carbon-containing film (21b) is formed on the first carbon-containing film (21a), holes or gaps contained in the first carbon-containing film (21a) can be filled by the second carbon-containing film (21b). Therefore, the characteristics of the carbon-containing film (20), for example, electrical characteristics, can be improved.

[0120] In addition, the first carbon-containing film (21a) can be crystallized by forming a plasma after injecting the first carbon-containing gas. That is, by forming a plasma, a crystalline first carbon-containing film (21a) can be formed at a low temperature of 100°C to 700°C. Accordingly, damage to at least one of the first carbon-containing film (21a), the lower film of the carbon-containing film (20), and the substrate (10) due to high heat can be suppressed or prevented.

[0121] In addition, when each of the first and second process cycles (CY1, CY2) is performed two or more times, a crystalline first carbon-containing film (21a) can be formed on an amorphous second carbon-containing film (21b). Here, the second carbon-containing film (21b) may have a high radical density due to nitrogen. Therefore, when crystallizing the first carbon-containing film (21a) on the second carbon-containing film (21b), nucleation of the first carbon-containing film (21a) may be facilitated, and growth in the vertical direction may be promoted.

[0122]

[0123] According to the embodiments as described above, a crystalline carbon-containing film (20) can be easily formed at a low temperature. That is, by forming a plasma inside a chamber in which a substrate (10) is loaded, the carbon-containing film can be easily crystallized in a low-temperature environment. Accordingly, when crystallizing the carbon-containing film, damage to at least one of the substrate (10) and the lower film by high-temperature heat can be suppressed or prevented.

[0124] Furthermore, by forming an amorphous carbon-containing film on a crystalline carbon-containing film, defects formed in the crystalline carbon-containing film can be filled. Therefore, there is an effect of improving the properties of the carbon-containing film. In addition, when crystallizing the carbon-containing film, nucleation can be facilitated and the growth rate can be improved.

[0125]

[0126] Figure 11 is a diagram showing a thin-film transistor.

[0127] The carbon-containing film according to the embodiments of the present invention can be used as a channel layer of a thin-film transistor. That is, the method for forming the carbon-containing film according to the embodiments of the present invention can be used to form the channel layer of a thin-film transistor. Therefore, for convenience of explanation, the reference numeral '20' is used below to denote the channel layer, identical to that of the carbon-containing film according to the embodiments.

[0128] First, a thin-film transistor will be described with reference to Fig. 11.

[0129] A thin-film transistor may include a substrate (10), a gate electrode (11) formed on the substrate (10), a channel layer (20) formed on the gate electrode (11), and a source electrode (13a) and a drain electrode (13b) formed on the channel layer (20) so as to be spaced apart from each other. At this time, the source electrode (13a) and the drain electrode (13b) may also be formed on a gate insulating layer (12) exposed to the outside of the channel layer (20). Furthermore, the source electrode (13a) and the drain electrode (13b) may be spaced apart by a predetermined distance. Accordingly, a portion of the channel layer (20) may be exposed in the spaced-apart area between the source electrode (13a) and the drain electrode (13b). The channel layer (20) may also be referred to as an active layer.

[0130] The channel layer (20) may be a carbon-containing film (20) according to embodiments of the present invention. That is, the channel layer (20) may be a nitrogen-doped carbon-containing film (20). Additionally, the channel layer (20) may be a carbon-containing film (20) formed by any one of the first to fourth embodiments.

[0131] When forming a carbon-containing film (or channel layer) by any one of the first to fourth embodiments, a gate electrode (11) and a gate insulating layer (12) may be formed on the substrate (10). Then, a carbon-containing film may be formed on the gate insulating layer (12) to form a channel layer (20) by any one of the first to fourth embodiments.

[0132] Accordingly, by forming a channel layer (carbon-containing film) on the gate insulating layer (12) by the method according to the embodiments, damage to the gate insulating layer (12) by high heat can be suppressed or prevented. Accordingly, the performance of the thin-film transistor can be improved.

[0133] According to embodiments of the present invention, a crystalline carbon-containing film can be easily formed at a low temperature. Accordingly, when forming a crystalline carbon-containing film, damage to one or more of the substrate and the underlying film by high-temperature heat can be suppressed or prevented.

Claims

1. A method for forming a carbon-containing film inside a chamber containing a substrate, wherein A step of injecting a carbon-containing gas into the interior of the chamber; and A method for forming a carbon-containing film comprising the step of forming a direct plasma inside the chamber.

2. In Claim 1, The step of forming the above direct plasma is, A method for forming a carbon-containing film by forming a plasma using a nitrogen-containing gas.

3. In Claim 2, The step of forming the above direct plasma is, A method for forming a carbon-containing film by further using a gas comprising one or more of argon (Ar), helium (He) and hydrogen (H) to form a plasma.

4. A method for forming a carbon-containing film inside a chamber in which a substrate is received, A step of injecting carbon-containing gas into the interior of the chamber; A step of forming a direct plasma using a gas containing one or more of argon (Ar), helium (He), and hydrogen (H) inside the chamber; and A method for forming a carbon-containing film comprising the step of forming a direct plasma using a nitrogen-containing gas inside the chamber.

5. A method for forming a carbon-containing film inside a chamber in which a substrate is received, A step of injecting carbon-containing gas into the interior of the chamber; A step of forming a direct plasma using a nitrogen-containing gas inside the chamber; and A method for forming a carbon-containing film comprising the step of forming a direct plasma using a gas containing one or more of argon (Ar), helium (He), and hydrogen (H) inside the chamber.

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