Patent Description:
In the field of semiconductor devices, studies on graphene have been actively conducted to address the increase of resistance caused by a decrease in the width of metal wiring and satisfy the necessity of new metal barrier material development. Graphene is a material having a hexagonal honeycomb structure formed by two-dimensionally connected carbon atoms, and the thickness of graphene is very small. Graphene may have an atom-size thickness. Such graphene may have high electrical mobility, satisfactory thermal characteristics, chemical stability, and a wide surface area compared to silicon (Si).

Document <CIT> discloses a method for preparing a free or transferrable graphene sheet comprising pre-treating the surface of a polycrystalline copper sulfate with a Hydrogen-containing plasma.

Document <NPL>, discloses synthesizing graphene of <NUM> to <NUM> layers on a polycrystalline Co film by radio-frequency plasma-enhances chemical vapor deposition.

Document <CIT> discloses a method for growing graphene on a surface of a gate electrode and a method for growing graphene on a surface of a source.

Provided are methods of directly forming graphene on a substrate.

According to an aspect of an embodiment, there is provided a method of forming graphene according to claim <NUM>.

In some embodiments, the treating the surface of the substrate may include forming at least one of charges and activation sites inducing adsorption of activated carbon on the surface of the substrate. The activation sites may include at least one of roughness and defects.

In some embodiments, the treating the surface of the substrate may include: injecting a pretreatment gas into the reaction chamber; applying the bias to the substrate; and generating the plasma in the reaction chamber while applying the bias to the substrate.

In some embodiments, the pretreatment gas may include at least one of an inert gas, hydrogen, oxygen, ammonia, chlorine, bromine, fluorine, and fluorocarbon.

In some embodiments, the applying bias to the substrate may include supplying a bias power to the substrate. The bias power may range from about <NUM> W to about <NUM> W.

In some embodiments, the reaction gas may further include at least one of an inert gas and hydrogen gas.

In some embodiments, the treating the surface of the substrate may be performed at a lower processing pressure than the growing the graphene.

In some embodiments, the plasma used in the treating the surface of the substrate may be generated by at least one a radio frequency (RF) plasma generating device or a microwave (MW) plasma generating device. The plasma used in the growing the graphene may be generated by at least one a radio frequency (RF) plasma generating device or a microwave (MW) plasma generating device.

In some embodiments, the growing the graphene further may include applying a bias to the substrate.

According to an aspect of another embodiment, a method of forming graphene may include: treating a surface of a substrate by applying a bias to the substrate; and growing graphene on the surface of the substrate.

In some embodiments, the treating the surface of the substrate may include: injecting a pretreatment gas into a reaction chamber; applying the bias to the substrate; and generating plasma in the reaction chamber while applying the bias to the substrate.

In some embodiments, the growing the graphene may include: injecting a reaction gas including a carbon source into a reaction chamber; and directly growing the graphene on the surface of the substrate by generating plasma in the reaction chamber.

According to an aspect of another embodiment, a method of forming graphene may include: preparing a substrate including a plasma-treated surface and growing graphene on the plasma-treated surface of the substrate by plasma enhanced chemical vapor deposition (PECVD). The preparing the substrate may include performing a plasma operation on the substrate while applying a bias to the substrate.

In some embodiments, the preparing the substrate may include placing the substrate including the plasma-treated surface in a reaction chamber, injecting a pretreatment gas into the reaction chamber, applying the bias to the substrate, and generating a plasma in the reaction chamber while applying the bias to the substrate in the reaction chamber.

In some embodiments, the pretreatment gas may include at least one of an of an inert gas, hydrogen, oxygen, ammonia, chlorine, bromine, fluorine, and fluorocarbon. The substrate may include at least one of a group IV semiconductor material, a semiconductor compound, a metal, and an insulating material.

In some embodiments, the preparing the substrate may be performed at a processing temperature of about <NUM> or less, a processing pressure in a range of about <NUM> torr to about <NUM> torr, a bias power in a range from about <NUM> W to about <NUM> W, and a plasma power in range from about <NUM> W to about <NUM> W.

In some embodiments, the growing graphene on the plasma-treated surface of the substrate may include injecting a reaction gas including a carbon source into a reaction chamber, and generating a plasma in the reaction chamber from the reaction gas while the substrate including the plasma-treated surface is in the reaction chamber.

These and/or other aspects will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings in which:.

In the drawings, like reference numerals refer to like elements, and the sizes of elements may be exaggerated for clarity of illustration. Expressions such as "at least one of," when preceding a list of elements (e.g., A, B, and C), modify the entire list of elements and do not modify the individual elements of the list. For example, "at least one of A, B, and C," and "at least one of A, B, or C" may be construed as covering any one of the following combinations: A; B; A and B; A and C; B and C; and A, B, and C.

In the following description, when an element is referred to as being "above" or "on" another element, it may be directly on the other element while making contact with the other element or may be above the other element without making contact with the other element. The terms of a singular form may include plural forms unless otherwise mentioned. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features or elements, but do not preclude the presence or addition of one or more other features or elements.

An element referred to with the definite article or a demonstrative pronoun may be construed as the element or the elements even though it has a singular form. Operations of a method may be performed in appropriate order unless explicitly described in terms of order or described to the contrary. That is, operations are not limited to the order in which the operations are described. Examples or exemplary terms are just used herein to describe technical ideas and should not be considered for purposes of limitation unless defined by the claims.

Graphene is a material having a hexagonal honeycomb structure formed by two-dimensionally connected carbon atoms, and the thickness of graphene is very small, that is, graphene has an atom-size thickness. Such graphene has high electrical mobility, satisfactory thermal characteristics, chemical stability, and a wide surface area compared to silicon (Si). In the following embodiments, a method of forming graphene will be described.

<FIG> are views illustrating a method of forming graphene according to an example embodiment that includes a substrate pretreatment process and a graphene growth process. <FIG> are views illustrating the substrate pretreatment process, and <FIG> are views illustrating the graphene growth process.

Hereinafter, the substrate pretreatment process will be first described with reference to <FIG>.

Referring to <FIG>, a pretreatment gas is injected into a reaction chamber (not shown) in which a substrate <NUM> is provided.

For example, the substrate <NUM> may include a semiconductor material. The semiconductor material may include, for example, a group IV semiconductor material or a semiconductor compound. For example, the group IV semiconductor material may include silicon (Si), germanium (Ge), or tin (Sn). In addition, for example, the semiconductor compound may include a material in which at least two of silicon (Si), germanium (Ge), carbon (C), zinc (Zn), cadmium (Cd), aluminum (Al), gallium (Ga), indium (In), boron (B), nitrogen (N), phosphorus (P), sulfur (S), selenium (Se), arsenic (As), antimony (Sb), and tellurium (Te) are combined with each other.

The substrate <NUM> may include a metal. For example, the metal may include at least one of copper (Cu), molybdenum (Mo), nickel (Ni), aluminum (Al), tungsten (W), ruthenium (Ru), cobalt (Co), manganese (Mn), titanium (Ti), tantalum (Ta), gold (Au), hafnium (Hf), zirconium (Zr), zinc (Zn), yttrium (Y), chromium (Cr), and gadolinium (Gd). In addition, the substrate <NUM> may include an insulating material. The insulating material may include, for example, an oxide, a nitride, a carbide, or the like. The above-mentioned materials of the substrate <NUM> are merely examples, and the substrate <NUM> may include various other materials. In addition, the substrate <NUM> may further include a dopant. The substrate <NUM> may include a surface 110a.

For example, the pretreatment gas injected into the reaction chamber in the substrate pretreatment process may include at least one of an inert gas, hydrogen, oxygen, ammonia, chlorine, bromine, fluorine, and fluorocarbon. For example, the inert gas may include at least one of argon gas, neon gas, nitrogen gas, helium gas, krypton gas, and xenon gas. <FIG> shows an example in which hydrogen is used as the pretreatment gas.

Next, a bias is applied to the substrate <NUM> using a bias supply <NUM>. The bias applied to the substrate <NUM> may be, for example, a radio frequency (RF) bias or a direct current (DC) bias. Accordingly, a positive (+) bias voltage or a negative (-) bias voltage may be applied to the substrate <NUM>. To this end, bias power having a given value may be applied to the substrate <NUM>. For example, the bias power applied to the substrate <NUM> in the substrate pretreatment process may range from about <NUM> W to about <NUM> W. However, this is merely an example, and the bias power applied to the substrate <NUM> may be diversely varied.

Referring to <FIG>, in a state in which the bias is applied to the substrate <NUM>, power for generating plasma is applied to the inside of the reaction chamber from a plasma power source (not shown). The plasma power applied in the substrate pretreatment process is greater than plasma power applied in the graphene growth process described later. For example, the plasma power applied in the substrate pretreatment process may range from about <NUM> W to about <NUM> W.

For example, the plasma power supply may be an RF plasma generating device or a microwave (MW) plasma generating device. The RF plasma generating device may generate RF plasma, for example, within a frequency range of about <NUM> to about <NUM>, and the MW plasma generating device may generate MW plasma, for example, within a frequency range of about <NUM> to about <NUM>. However, these frequency ranges are merely examples. That is, other frequency ranges may be used. Alternatively, the plasma power supply may include a plurality of RF plasma generating devices or a plurality of MW plasma generating devices.

Referring to <FIG>, when plasma power is applied to the inside of the reaction chamber in a state in which a bias is applied to the substrate <NUM>, gas plasma (for example, hydrogen plasma) may be generated in the reaction chamber. As described above, when gas plasma is generated in the reaction chamber in a state in which a bias applied to the substrate <NUM>, charges <NUM> may be formed on the surface 110a of the substrate <NUM>. For example, positive (+) charges <NUM> may be formed on the surface 110a of the substrate <NUM> as shown in <FIG> when a negative (-) bias voltage is applied to the substrate <NUM>. Alternatively, negative (-) charges may be formed on the surface 110a of the substrate <NUM> when a positive (+) bias voltage is applied to the substrate <NUM>.

The charges <NUM> formed on the surface 110a of the substrate <NUM> by applying plasma power in a state in which a bias is applied to the substrate <NUM> may induce adsorption of activated carbon <NUM> (refer to <FIG>) in the graphene growth process described later.

When gas plasma is generated by applying plasma power in a state in which a bias is applied to the substrate <NUM>, activation sites <NUM> (refer to <FIG>) capable of inducing adsorption of activated carbon <NUM> (refer to <FIG>) may be formed on the surface 110a of the substrate <NUM>.

<FIG> shows the activation sites <NUM> formed on the surface 110a of the substrate <NUM> by applying plasma power in a state in which a bias is applied to the substrate <NUM>. Referring to <FIG>, when plasma is generated by applying plasma power in a state in which a bias is applied to the substrate <NUM>, charges <NUM> may move toward the substrate <NUM> and may collide with the surface 110a of the substrate <NUM> in the reaction chamber. Accordingly, the activation sites <NUM> may be formed on the surface 110a of the substrate <NUM>, and the activation sites <NUM> may induce adsorption of activated carbon <NUM> (refer to <FIG>) in the graphene growth process described later. Here, the activation sites <NUM> may include, for example, roughness or defects. <FIG> illustrates roughness as an example of the activation sites <NUM>.

When gas plasma is generated by applying plasma power in a state in which a bias is applied to the substrate <NUM>, charges <NUM> and activation sites <NUM> capable of inducing adsorption of activated carbon <NUM> (refer to <FIG>) may all be formed on the surface 110a of the substrate <NUM>.

<FIG> illustrates charges <NUM> and activation sites <NUM> formed on the surface 110a of the substrate <NUM> by applying plasma power in a state in which a bias is applied to the substrate <NUM>. Referring to <FIG>, when plasma is generated by applying plasma power in a state in which a bias is applied to the substrate <NUM>, charges <NUM> may move toward the substrate <NUM> in the reaction chamber. In this process, some of the charges <NUM> may be formed on the surface 110a of the substrate <NUM>, and the other of the charges <NUM> may collide with the surface 110a of the substrate <NUM> and may form the activation sites <NUM>. Here, the activation sites <NUM> may include, for example, roughness or defects.

In the substrate pretreatment process, the processing temperature and the processing pressure of the inside of the reaction chamber may be varied diversely according to growth conditions of graphene. For example, the substrate pretreatment process may be performed at a relatively low temperature. For example, the substrate pretreatment process may be performed at a processing temperature of about <NUM> or less. For example, the substrate pretreatment process may be performed at a processing temperature of about <NUM> or less (for example, about <NUM> or less). In addition, for example, the processing pressure at which the substrate pretreatment process is performed may be less than the processing pressure at which the graphene growth process (described later) is performed. However, this is a non-limiting example. That is, the processing pressure at which the substrate pretreatment process is performed may be variously varied according to growth conditions of graphene. For example, the processing pressure at which the substrate pretreatment process is performed may range from about <NUM> torr to about <NUM> torr.

At least one of the charges <NUM> and the activation sites <NUM> capable of inducing adsorption of activated carbon <NUM> (refer to <FIG>) may be formed on the surface 110a of the substrate <NUM> through the above-described substrate pretreatment process. Owing to the charges <NUM> or the activation sites <NUM> formed on the surface 110a of the substrate <NUM>, activated carbon <NUM> (refer to <FIG>) may be effectively adsorbed on the surface 110a of the substrate <NUM> in the graphene growth process (described later), and thus graphene <NUM> (refer to <FIG>) may be directly grown and formed on the surface 110a of the substrate <NUM> at a relatively low temperature of about <NUM> or less.

Hereinafter, a process of growing graphene <NUM> (refer to <FIG>) on the surface 110a of the substrate <NUM> on which the substrate pretreatment process has been performed as described above will be described with reference to <FIG>. As described above, at least one of the charges <NUM> and the activation sites <NUM> capable of inducing adsorption of activated carbon <NUM> (refer to <FIG>) may be formed on the surface 110a of the substrate <NUM> through the above-described substrate pretreatment process. In <FIG>, the charges <NUM> and the activation sites <NUM> formed on the surface 110a of the substrate <NUM> through the substrate pretreatment process are not shown for convenience sake.

<FIG> illustrate operations for growing graphene <NUM> on the surface 110a of the substrate <NUM> by plasma enhanced chemical vapor deposition (PECVD).

Referring to <FIG>, after the substrate pretreatment process, reaction gas for growing graphene <NUM> is injected into the reaction chamber. Here, the reaction gas may include a carbon source. Here, the carbon source may be a source for supplying carbon for growing the graphene <NUM>.

For example, the carbon source may include at least one of hydrocarbon gas and vapor of a liquid precursor containing carbon. For example, the hydrocarbon gas may include methane gas, ethylene gas, acetylene gas, or propylene gas, a sub-combination thereof, or a combination thereof. In addition, the liquid precursor containing carbon may include, for example, benzene, toluene, xylene, anisole, hexane, octane, isopropyl alcohol, ethanol, a sub-combination thereof, or a combination thereof, or the like. However, the carbon source materials mentioned above are merely examples. That is, various other materials may be used as the carbon source.

The reaction gas may further include at least one of an inert gas and hydrogen gas. For example, the inert gas may include at least one of argon gas, neon gas, nitrogen gas, helium gas, krypton gas, and xenon gas. <FIG> illustrates an example in which the reaction gas includes a carbon source, an inert gas, and hydrogen gas, wherein acetylene gas and argon gas are respectively used as the carbon source the inert gas. Meanwhile, the mixing ratio of the reaction gas injected into the reaction chamber may be diversely varied according to growth conditions of the graphene <NUM>.

Referring to <FIG>, power for generating plasma inside the reaction chamber is applied from a plasma power supply (not shown). The plasma power applied in the graphene growth process is less than the plasma power applied in the substrate pretreatment process.

For example, the plasma power supply may be an RF plasma generating device or an MW plasma generating device. The RF plasma generating device may generate RF plasma, for example, within a frequency range of about <NUM> to about <NUM>, and the MW plasma generating device may generate MW plasma, for example, within a frequency range of about <NUM> to about <NUM>. However, these frequency ranges are merely examples. That is, other frequency ranges may be used. Alternatively, the plasma power supply may include a plurality of RF plasma generating devices or a plurality of MW plasma generating devices.

When power for generating plasma inside the reaction chamber is applied from the plasma power supply, plasma of the reaction gas may be generated in the reaction chamber. In addition, activated carbon <NUM> (refer to <FIG>), for example, activated carbon source radicals, may be formed in the reaction chamber by the plasma of the reaction gas.

Referring to <FIG>, carbon <NUM> activated by the plasma of the reaction gas, that is, carbon source radicals, is adsorbed on the surface 110a of the substrate <NUM>. Here, as described above, since at least one of the charges <NUM> (refer to <FIG>) and the activation sites <NUM> (refer to <FIG>) capable of inducing adsorption of the activated carbon <NUM> are formed on the surface 110a of the substrate <NUM> through the substrate pretreatment process, the activated carbon <NUM> may be more effectively adsorbed on the surface 110a of the substrate <NUM> owing to the charges <NUM> and the activation sites <NUM>.

Referring to <FIG>, as described above, as the activated carbon <NUM> is continuously adsorbed on the surface 110a of the substrate <NUM>, graphene <NUM> may be grown and formed on the surface 110a of the substrate <NUM>. In this case, carbides may be formed on the surface 110a of the substrate <NUM> that is in contact with the graphene <NUM> because carbon combines with a substrate material.

In the graphene growth process, the processing temperature and the processing pressure of the inside of the reaction chamber may be diversely varied according to growth conditions of graphene. For example, the graphene growth process may be performed at a relatively low temperature like the substrate pretreatment process. For example, the graphene growth process may be performed at a processing temperature of about <NUM> or less. For example, the graphene growth process may be performed at a processing temperature of about <NUM> or less.

The processing pressure at which the graphene growth process is performed may be greater than the processing pressure of the above-described substrate pretreatment process. However, this is a non-limiting example. That is, the processing pressure at which the graphene growth process is performed may be diversely varied according to growth conditions of graphene.

As described above, in the substrate pretreatment process, a bias is applied to the substrate <NUM>, and plasma is generated such that charges <NUM> or activation sites <NUM> capable of inducing adsorption of activated carbon <NUM> may be formed on the surface 110a of the substrate <NUM>. Therefore, owing to the charges <NUM> or the activation sites <NUM>, activated carbon <NUM> may be more effectively adsorbed on the surface 110a of the substrate <NUM> in the graphene growth process. Therefore, the graphene <NUM> may be directly grown on the surface 110a of the substrate <NUM> at a relatively low temperature.

For example, when a semiconductor device including graphene that may be used as a metal barrier material is fabricated, it may be necessary to directly grow graphene on a non-catalytic substrate at a relatively low temperature of about <NUM> or less. According to the example embodiment, the substrate pretreatment process may be performed at a relatively low temperature to induce adsorption of activated carbon <NUM> on the surface 110a of the substrate <NUM>, and graphene <NUM> may be directly grown and formed on the pretreated surface 110a of the substrate <NUM> by PECVD. Therefore, a semiconductor device including graphene may be easily fabricated through low-temperature processes.

<FIG> illustrates Raman spectra measured from surfaces of silicon substrates after graphene was grown on the surfaces of the silicon substrates according to a first method (a process that includes applying a bias to a silicon substrate in a pretreatment process of the silicon substrate (curve B)) and a second method (a process that does not include applying a bias to a silicon substrate in a pretreatment process of the silicon substrate (curve A)). <FIG> illustrates results when bias power of <NUM> W was applied to the silicon substrate for <NUM> minutes.

Referring to <FIG>, Raman peaks were greater when a bias was applied to the silicon substrate in the pretreatment process of the silicon substrate (curve B) than when a bias was not applied to the silicon substrate in the pretreatment process of the silicon substrate (curve A). Therefore, it could be understood that it is possible to directly grow graphene on a surface of a silicon substrate even at a relatively low temperature of about <NUM> or less by applying a bias to the silicon substrate in a pretreatment process of the silicon substrate.

<FIG> illustrates the amounts of Si-C bonds formed on surfaces of silicon substrates after graphene was grown on the surfaces of the silicon substrates according to a first method (a process that includes applying a bias to a silicon substrate in a pretreatment process of the silicon substrate (curve D)) and a second method (a process that does not include applying a bias to a silicon substrate in a pretreatment process of the silicon substrate (curve C)). <FIG> illustrates results when bias power of <NUM> W was applied to the silicon substrate for <NUM> minutes.

Referring to <FIG>, more Si-C bonds were formed when a bias was applied to the silicon substrate in the pretreatment process of the silicon substrate (curve D) than when a bias was not applied to the silicon substrate in the pretreatment process of the silicon substrate (curve C). Accordingly, it could be understood that it is possible to increase the bonding strength between a silicon substrate and graphene by applying a bias to the silicon substrate in a pretreatment process of the silicon substrate.

<FIG> are views illustrating a method of forming graphene according to another example embodiment.

The method of forming graphene of the present embodiment includes a substrate pretreatment process and a graphene growing process. The substrate pretreatment process is the same as the substrate pretreatment process illustrated with reference to <FIG>, and thus a description thereof will not be presented here. However, in the present embodiment, for example, a trench having a given shape may be formed in a substrate <NUM>. As described above, at least one of charges and activation sites capable of inducing adsorption of activated carbon may be formed on a surface of the substrate <NUM> through the substrate pretreatment process.

Hereinafter, the graphene growth process performed after the substrate pretreatment process will be described with reference to <FIG> illustrate operations for growing graphene <NUM> on the substrate <NUM> by PECVD. In <FIG>, charges and activation sites formed on the surface of the substrate <NUM> by the substrate pretreatment process are not shown for convenience sake.

Referring to <FIG>, after the substrate pretreatment process, reaction gas for growing graphene <NUM> (refer to <FIG>) is injected into a reaction chamber. Here, the reaction gas may include a carbon source. For example, the carbon source may include at least one of hydrocarbon gas and vapor of a liquid precursor containing carbon.

The reaction gas may further include at least one of an inert gas and hydrogen gas. For example, the inert gas may include at least one of argon gas, neon gas, nitrogen gas, helium gas, krypton gas, and xenon gas. <FIG> illustrates an example in which the reaction gas includes a carbon source, an inert gas, and hydrogen gas, wherein acetylene gas and argon gas are respectively used as the carbon source the inert gas.

Next, a bias is applied to the substrate <NUM> using a bias supply <NUM>. The bias applied to the substrate <NUM> may be, for example, an RF bias or a DC bias. Here, bias power applied to the substrate <NUM> may be diversely varied. Accordingly, a positive (+) bias voltage or a negative (-) bias voltage may be applied to the substrate <NUM>. Next, in a state in which the bias is applied to the substrate <NUM>, power for generating plasma is applied to the inside of the reaction chamber from a plasma power source (not shown). For example, the plasma power supply may be an RF plasma generating device or an MW plasma generating device. Alternatively, the plasma power supply may include a plurality of RF plasma generating devices or a plurality of MW plasma generating devices.

When power for generating plasma inside the reaction chamber is applied from the plasma power supply, plasma of the reaction gas may be generated in the reaction chamber. In addition, activated carbon <NUM>, for example, activated carbon source radicals, may be formed in the reaction chamber by the plasma of the reaction gas.

The activated carbon <NUM> generated by the plasma of reaction gas, that is, carbon source radicals, is adsorbed on the surface of the substrate <NUM>. In this case, since the bias is applied to the substrate <NUM>, the activated carbon <NUM> generated by the plasma of the reactive gas may move linearly toward the substrate <NUM>. Thus, the activated carbon <NUM> may be attached to a selected region of the substrate <NUM>. For example, since the activated carbon <NUM> moves linearly toward the substrate <NUM> as illustrated in <FIG>, the activated carbon <NUM> may be selectively absorbed to a bottom surface 210a of the trench instead of being attached to slopes 210b of the trench.

In addition, since charges or activation sites capable of inducing adsorption of activated carbon <NUM> are formed on the surface of the substrate <NUM> by the substrate pretreatment process, the activated carbon <NUM> may be more effectively adsorbed on the bottom surface 210a of the trench.

Referring to <FIG>, as the activated carbon <NUM> is continuously adsorbed on the surface of the substrate <NUM>, for example, on the bottom surface 210a of the trench, graphene <NUM> may be selectively grown and formed on the bottom surface 210a of the trench.

In the graphene growth process, the processing temperature and the processing pressure of the inside of the reaction chamber may be diversely varied according to growth conditions of graphene. For example, the graphene growth process may be performed at a processing temperature of about <NUM> or less (for example, about <NUM> or less).

As described above, since plasma of the reaction gas is generated in a state in which a bias is applied to the substrate <NUM> in the graphene growth process, the graphene <NUM> may be grown by causing the activated carbon <NUM> to be selectively adsorbed on a surface of the substrate <NUM>, for example, on the bottom surface 210a of the trench.

<FIG> is a cross-sectional view of an apparatus for forming graphene according to some example embodiments.

Referring to <FIG>, an apparatus <NUM> may include a gas supply <NUM>, a process chamber <NUM>, a plasma generation unit <NUM>, a substrate transporter <NUM>, a pumping system <NUM>, a heater <NUM>, a power supply <NUM>, and an operation station <NUM>. The process chamber <NUM> may include a chamber housing <NUM>, an upper electrode <NUM> in the chamber housing <NUM>, and a substrate support <NUM> in the chamber housing <NUM>. The upper electrode <NUM> may be connected to a gas supply <NUM> with conduits and gas flow controllers for providing reaction gases into the process chamber <NUM>. The substrate support <NUM> may be an electrostatic chuck, but is not limited thereto.

A substrate transporter <NUM>, such as a robot arm, may transport a substrate <NUM> into and out of the process chamber <NUM>. The process chamber <NUM> may include a gate valve that opens when the substrate transporter <NUM> transports the substrate <NUM> into or out of the process chamber <NUM> and closes when the process chamber <NUM> performs operations (e.g., vacuum processes). A heater <NUM> (e.g., electric heater) may control the temperature of the substrate support <NUM>, inner wall of process chamber <NUM>, and upper electrode <NUM>. The plasma generation unit <NUM> may be a RF power generator and may be connected to the substrate support <NUM> and may be used to generate a plasma P of a reaction gas in the process chamber <NUM>. Alternatively, a microwave power supply may be used to generate the plasma P in the process chamber <NUM>. A pumping system <NUM> connected to the process chamber <NUM> may create a vacuum in the process chamber <NUM>. A power supply <NUM> (e.g., circuit) may provide electrical power to the apparatus <NUM>.

The operation station <NUM> may control operations of the apparatus <NUM>. The operation station <NUM> may include a controller <NUM>, a memory <NUM>, a display <NUM> (e.g., monitor), and an input and output device <NUM>. The memory <NUM> may include a nonvolatile memory, such as a flash memory, a phase-change random access memory (PRAM), a magneto-resistive RAM (MRAM), a resistive RAM (ReRAM), or a ferro-electric RAM (FRAM), and/or a volatile memory, such as a static RAM (SRAM), a dynamic RAM (DRAM), or a synchronous DRAM (SDRAM). The input and output device <NUM> may be a keyboard and/or a touch screen.

The memory <NUM> may store an operating system and may store recipe instructions that include settings (e.g., gas flow rates, temperature, time, power, pressure, etc.) for different manufacturing processes performed by the apparatus <NUM>. The memory <NUM> may store recipe instructions for forming a graphene product on the substrate <NUM> according to one or more of the embodiments in <FIG> and/or <NUM> to <NUM> of the present application.

The controller <NUM> may be, a central processing unit (CPU), a controller, or an application-specific integrated circuit (ASIC), that when, executing recipe instructions stored in the memory <NUM> (for one or more of the embodiments in <FIG> and/or <NUM> to <NUM>) configures the controller <NUM> as a special purpose controller that operates apparatus <NUM> to form a graphene according to example embodiments on the substrate <NUM>.

As described above, according to the one or more of the above example embodiments, in the substrate pretreatment process, a bias is applied to a substrate, and plasma is used such that charges or activation sites capable of inducing adsorption of activated carbon on the surface of the substrate may be formed. Therefore, in the graphene growth process, activated carbon may be more effectively adsorbed on the surface of the substrate, and thus graphene may be grown and formed on the surface of the substrate at a relatively low temperature. Furthermore, in the graphene growth process, a bias may be applied to the substrate to selectively grow graphene on a selected surface of the substrate.

For example, when a semiconductor device including graphene that may be used as a metal barrier material is fabricated, it may be necessary to directly grow graphene on a non-catalytic substrate at a relatively low temperature of about <NUM> or less. According to the example embodiments, the substrate pretreatment process may be performed at a relatively low temperature to induce adsorption of activated carbon on the surface of the substrate, and graphene may be directly grown and formed on the pretreated surface of the substrate by PECVD. Therefore, a semiconductor device including graphene may be easily fabricated through low-temperature processes.

Claim 1:
A method of forming graphene, the method comprising:
treating a surface of a substrate placed in a reaction chamber with plasma while applying a bias to the substrate, wherein the substrate includes at least one of a group IV semiconductor material, a semiconductor compound, a metal, and an insulating material, and optionally wherein the substrate further includes a dopant, wherein the treating the surface of the substrate is performed at a processing pressure of <NUM> torr to <NUM> torr and a plasma power in the treating the surface of the substrate ranges from <NUM> W to <NUM> W; and
growing graphene on the surface of the substrate by plasma enhanced chemical vapor deposition, PECVD, wherein the treating the surface of the substrate and the growing the graphene are performed at a processing temperature of <NUM> or less, and wherein the growing of the graphene includes:
injecting a reaction gas including a carbon source into the reaction chamber; and
directly growing the graphene on the surface of the substrate by generating plasma in the reaction chamber;
and characterized in that:
the plasma power in the treating the surface of the substrate is greater than a plasma power in the growing of the graphene..