Method for calculating the thickness of the graphite layer and measuring the silicon carbide content with XPS

Abstract

Provided are a method of measuring a thickness of a graphene layer and a method of measuring a content of silicon carbide by using X-ray photoelectron spectroscopy (XPS). The method of calculating a thickness of a graphene layer directly grown on a silicon substrate includes measuring a thickness of a graphene layer directly grown on a silicon substrate by using a ratio between a signal intensity of a photoelectron beam emitted from the graphene layer and a signal intensity of a photoelectron beam emitted from the silicon substrate.

Description

Technical Field

[0001] One or more embodiments relate to methods for calculating the thickness of a graphene layer grown directly on a silicon substrate using X-ray photoelectron spectroscopy (XPS) and methods for measuring the content of silicon carbides included in the interface layer between the silicon substrate and the graphene layer. Background Technology

[0002] In the field of semiconductor devices, research on graphene has been actively pursued to address the increasing resistance as the width of metal interconnects decreases and to develop new metal barrier materials. Graphene is a material formed from two-dimensionally interconnected carbon atoms with a hexagonal honeycomb structure. Graphene has an extremely small thickness at the atomic scale. Compared to silicon, graphene exhibits superior electrophoretic properties and possesses numerous advantages, such as excellent thermal properties, chemical stability, and a large surface area. Summary of the Invention

[0003] One or more example embodiments provide a method for calculating the thickness of a graphene layer grown directly on a silicon substrate using X-ray photoelectron spectroscopy (XPS) and a method for measuring the content of silicon carbide included in the interface layer between the silicon substrate and the graphene layer.

[0004] Other aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments presented in this disclosure.

[0005] According to one embodiment, a method is provided for measuring the thickness of a graphene layer directly grown on a silicon substrate using an X-ray photoelectron spectroscopy (XPS) instrument. The method includes: using an XPS instrument, in response to emitting X-ray radiation towards the graphene layer directly grown on the silicon substrate, obtaining a signal intensity from the graphene layer directly grown on the silicon substrate; and calculating the thickness t of the graphene layer according to the following equation. G :

[0006]

[0007] in

[0008] λ EAL It is the effective attenuation length, α is the detection angle of the XPS instrument, and I co I is the signal intensity of the photoelectron beam emitted from bulk graphene. sio I is the signal intensity of the photoelectron beam emitted from bulk silicon. c I is the signal intensity of the photoelectron beam emitted from the graphene layer in response to X-ray radiation received by the graphene layer through the XPS instrument and detected by sensors on the XPS instrument. siIt is the signal intensity of the photoelectron beam emitted from the silicon substrate in response to X-ray radiation received by the XPS instrument and detected by a sensor on the XPS instrument, wherein

[0009] XPS instruments can detect the signal intensity I of the photoelectron beam emitted from a silicon substrate. si and the signal intensity I of the photoelectron beam emitted from the graphene layer c The linear relationship between them yields R0.

[0010] In some embodiments, the graphene layer may include crystalline graphene or nanocrystalline graphene.

[0011] In some implementations, the effective attenuation length can be obtained through calibration based on the linear relationship between the results measured by transmission electron microscopy and the results measured by XPS.

[0012] In some implementations, bulk graphene may have a thickness greater than or equal to about 10 nm.

[0013] According to another embodiment, a method is provided for measuring the thickness of a graphene layer directly grown on a silicon substrate using an X-ray photoelectron spectroscopy (XPS) instrument. An interface layer is formed between the silicon substrate and the graphene layer. The method includes: using an XPS instrument, in response to emitting X-ray radiation toward the graphene layer directly grown on the silicon substrate, obtaining a signal intensity from the graphene layer directly grown on the silicon substrate; and calculating the thickness t of the graphene layer according to the following equation. G ,

[0014]

[0015] in

[0016] λ EAL It is the effective attenuation length, α is the detection angle of the XPS instrument, and I co I is the signal intensity of the photoelectron beam emitted from bulk graphene. sio I is the signal intensity of the photoelectron beam emitted from bulk silicon. c I is the signal intensity of the photoelectron beam emitted from the graphene layer in response to X-ray radiation received by the graphene layer through the XPS instrument and detected by sensors on the XPS instrument. si K is the signal intensity of the photoelectron beam emitted from the silicon substrate in response to X-ray radiation received by the XPS instrument and detected by a sensor on the XPS instrument. K is a correction value based on the effect of the interface layer.

[0017] XPS instruments can detect the signal intensity I of a photoelectron beam emitted from a silicon substrate. siand the signal intensity I of the photoelectron beam emitted from the graphene layer c The linear relationship between them yields R0.

[0018] In some embodiments, the interface layer includes silicon carbide, silicon carbide oxide, and silicon oxide.

[0019] In some embodiments, the graphene layer may include crystalline graphene or nanocrystalline graphene.

[0020] In some implementations, the effective attenuation length can be obtained through calibration based on the linear relationship between the results measured by transmission electron microscopy and the results measured by XPS.

[0021] According to another embodiment, a method is provided for measuring the content of silicon carbide in an interface layer comprising a silicon substrate and a graphene layer grown directly on the silicon substrate. The method includes measuring the content of silicon carbide using X-ray photoelectron spectroscopy (XPS) by utilizing the spectrum of a photoelectron beam emitted from the silicon substrate.

[0022] In some implementations, the interface layer may include silicon carbide, silicon carbide oxide, and silicon oxide.

[0023] In some implementations, the content of silicon carbide is measured based on the ratio of the composition of silicon carbide to the sum of the compositions of silicon carbide, silicon carbide oxide, and silicon oxide.

[0024] In some embodiments, the silicon carbide content is measured by calculating the ratio of the peak area of ​​silicon carbide to the sum of the peak areas of silicon carbide, silicon carbide, and silicon oxide in the spectrum of the photoelectron beam emitted on the silicon substrate. Attached Figure Description

[0025] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This shows a graphene layer grown directly on a silicon substrate;

[0027] Figure 2 An example of C1s spectrum of a photoelectron beam emitted from a graphene layer using X-ray photoelectron spectroscopy (XPS) is shown;

[0028] Figure 3 An example of the Si2p spectrum of a photoelectron beam emitted from a silicon substrate using XPS is shown;

[0029] Figure 4A The generation of photoelectron beams from graphene layers, their emission to the outside, and their detection are shown.

[0030] Figure 4B The diagram shows the relationship between the thickness of the graphene layer and the thickness of the graphene layer. Figure 4A The signal intensity of the photoelectron beam emitted by the graphene layer;

[0031] Figure 5A The generation, emission, and detection of a photoelectron beam from a silicon substrate are illustrated.

[0032] Figure 5B The diagram shows the results based on the thickness of the graphene layer, from... Figure 5A The signal intensity of the photoelectron beam emitted by the silicon substrate through the graphene layer;

[0033] Figure 6 This is a data graph showing the variation in the thickness of the graphene layer (nanocrystalline graphene) grown on the silicon substrate, and the signal intensity (I) of the photoelectron beam emitted from the silicon substrate. Si The measurement results and the signal intensity (I) of the photoelectron beam emitted from the graphene layer (nanocrystalline graphene) C The results of the measurement;

[0034] Figure 7 Another example of Si2p spectrum is shown using a photoelectron beam emitted from a silicon substrate via XPS.

[0035] Figure 8 The results show experimental findings regarding the variation in the content of silicon carbide in the interface layer formed between the silicon substrate and the graphene layer when the graphene layer is grown directly on a silicon substrate, with the variation occurring with changes in deposition process conditions.

[0036] Figure 9 This is a flowchart illustrating a method for manufacturing a graphene apparatus according to an example embodiment;

[0037] Figures 10A to 10D This is a cross-sectional view illustrating a method for manufacturing a graphene apparatus according to an exemplary embodiment; and

[0038] Figures 11A to 11D This is a cross-sectional view illustrating a method for manufacturing a graphene apparatus according to an example embodiment. Detailed Implementation

[0039] In the following description, exemplary embodiments will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals refer to the same parts, and the dimensions of parts may be exaggerated for clarity and ease of description. The embodiments described below are merely examples, and various modifications can be made according to these embodiments.

[0040] In the following text, when a component is referred to as “above” or “on” another component, the component may be directly on or indirectly on the other component, with an intervening component in between. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms, unless the context clearly indicates otherwise. Furthermore, when a component is referred to as “including” another component, it indicates that the component may further include, rather than exclude, other components, unless a specific description to the contrary exists.

[0041] The term "the" and other similar indicative words can be used in both singular and plural forms. Unless a specific order is described for the operations included in the method, or a contrary description exists, the operations may be performed in any appropriate order. This disclosure is not necessarily limited to the described order. All examples and exemplary terms are used to describe this disclosure in detail, and this disclosure is not limited to these examples and exemplary terms unless defined by the scope of the claims.

[0042] When the terms “approximately” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the associated numerical values ​​include manufacturing or operational tolerances (e.g., ±10%) around said values. Furthermore, when the words “usually” and “substantially” are used in conjunction with geometry, it is intended that precision of the geometry is not required, but the latitude of the shape is within the scope of this disclosure. Additionally, regardless of whether a numerical value or shape is modified to “approximately” or “substantially”, it will be understood that these values ​​and shapes should be interpreted as including manufacturing or operational tolerances (e.g., ±10%) around said values ​​or shapes.

[0043] Figure 1 A graphene layer 120 directly grown on a silicon substrate 110 is shown.

[0044] Reference Figure 1 The graphene layer 120 can be grown directly on the silicon substrate 110. In this case, an interface layer 130 can be further formed between the silicon substrate 110 and the graphene layer 120. Here, when silicon, carbon, oxygen, etc. are bonded on the silicon substrate 110, the interface layer 130 can be formed before the growth of the graphene layer 120. Alternatively, the interface layer 130 may not be formed between the silicon substrate 110 and the graphene layer 120.

[0045] The graphene layer 120 can be grown directly on the surface of the silicon substrate 110 without a catalyst using a deposition process. For example, the graphene layer 120 can be formed by thermochemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), etc. However, this is only one example. The graphene layer 120 can also be formed by atomic layer deposition (ALD), physical vapor deposition (PVD), etc.

[0046] Graphene layer 120 may comprise crystalline graphene or nanocrystalline graphene. The sp parameters can be obtained by measuring the D parameter via X-ray photoelectron spectroscopy (XPS). 2 The ratio of carbon in the bonded structure to all carbon. Specifically, based on the ratio of carbon in the sp... 2 The ratio of bonded carbon to total carbon can alter the peak shape of the Auger spectrum of carbon. The gap between the highest and lowest points in the D-parameter spectrum, formed by differentiating the peak shape, corresponds to the D-parameter. Therefore, crystalline graphene and nanocrystalline graphene can be distinguished by measuring the D-parameter in the Auger spectrum of carbon.

[0047] Crystalline graphene, also known as intrinsic graphene, can comprise crystals with dimensions, for example, larger than approximately 100 nm. In the case of crystalline graphene, the D parameter in the Auger spectrum of carbon can be approximately 23 eV. In this case, it has sp... 2 The ratio of carbon in the bonded structure to all carbon can be approximately 100%. Crystalline graphene may contain almost no hydrogen. Moreover, crystalline graphene may have a density of, for example, about 2.1 g / cc, and a sheet resistance of, for example, about 100 Ohm / sq to about 300 Ohm / sq. However, this disclosure is not limited thereto.

[0048] Nanocrystalline graphene can comprise crystals having a size smaller than that of crystalline graphene. For example, nanocrystalline graphene can comprise crystals with a size, for example, from about 0.5 nm to about 100 nm. In the case of nanocrystalline graphene, the D parameter in the Auger spectrum with respect to carbon can be from about 18 eV to about 22.9 eV. In this case, having sp 2 The ratio of carbon in the bonded structure to total carbon can be, for example, from about 50% to about 99%. Nanocrystalline graphene may include, for example, from about 1% to about 20% (atomic percentage) hydrogen. Furthermore, nanocrystalline graphene may have a density of, for example, from about 1.6 g / cc to about 2.1 g / cc, and a sheet resistance of, for example, greater than about 1000 Ohm / sq. However, this disclosure is not limited thereto.

[0049] An interface layer 130 may be formed between the silicon substrate 110 and the graphene layer 120. When silicon, carbon, oxygen, etc., are bonded, the interface layer 130 may be formed before the growth of the graphene layer 120. For example, the interface layer 130 may include: a silicon carbide in which silicon and carbon are bonded, a silicon carbide in which silicon, carbon, and oxygen are bonded, and a silicon oxide in which silicon and oxygen are bonded.

[0050] Figure 2 and Figure 3 It shows how to use XPS from Figure 1 Example spectrum of the photoelectron beam emitted by the structure shown.

[0051] Figure 2 An example C1s spectrum of a photoelectron beam emitted from graphene layer 120 using XPS is shown. Figure 2 In Csp 2 Indicates having sp 2 Csp, a carbon structure with bonded structure 3 Indicates having sp 3 Carbon in a bonded structure. Furthermore, SiOC represents silicon-carbon oxide, CO represents single-bonded carbon and oxygen, and C=O represents double-bonded carbon and oxygen. (See reference...) Figure 2 The graphene layer 120 includes nanocrystalline graphene, which has sp... 2 The proportion of carbon in the bonded structure, which corresponds to approximately 50% to approximately 99%.

[0052] Figure 3 An example Si2p spectrum is shown using a photoelectron beam emitted from a silicon substrate 110 via XPS. Figure 3 In this context, SiC represents silicon carbide, SiOC represents silicon carbide, and SiO represents silicon oxide. (See reference...) Figure 3 In addition to the silicon peak, SiC, SiOC, and SiO peaks were also detected. Therefore, it was determined that an interface layer 130 comprising SiC, SiOC, and SiO was formed between the silicon substrate 110 and the graphene layer 120.

[0053] Figure 4A The generation of a photoelectron beam from graphene layer 120, its emission to the outside, and its detection are illustrated. (Refer to...) Figure 4A When X-rays emitted from an X-ray source (not shown) are irradiated onto the graphene layer 120, a photoelectron beam can be generated from the graphene layer 120 and emitted to the outside, and the emitted photoelectron beam as described above can be detected by a detector (not shown). Figure 4A The photoelectron beam generated from graphene layer 120 is shown to be emitted at a specific angle α relative to the vertical direction of graphene layer 120 and detected.

[0054] Figure 4B The thickness of graphene layer 120 is shown as... Figure 4A The signal intensity of the photoelectron beam emitted from the graphene layer 120. The interaction formula between the signal intensity of the photoelectron beam emitted from the graphene layer 120 and the thickness t of the graphene layer 120 can be expressed as Equation 1 below.

[0055]

[0056] In Equation 1, "I C "I" represents the signal intensity of the photoelectron beam emitted from graphene layer 120. C0"λ" represents the signal intensity measured from the photoelectron beam emitted from bulk graphene. Here, bulk graphene can be a graphene bulk with a large thickness (e.g., equal to or greater than about 10 nm). c,c "α" represents the inelastic mean free path of the photoelectron beam generated from and transmitted through the graphene layer 120. Furthermore, "α" represents the detection angle of the photoelectron beam emitted from the graphene layer 120.

[0057] Figure 5A The generation, emission, and detection of a photoelectron beam generated from a silicon substrate 110 are illustrated. (Refer to...) Figure 5A When X-rays emitted from the X-ray source and transmitted through the graphene layer 120 irradiate the silicon substrate 110, a photoelectron beam can be generated from the silicon substrate 110 and emitted to the outside, and the emitted photoelectron beam can be detected by a detector. Figure 5A The photoelectron beam generated from silicon substrate 110 is shown to be emitted at a specific angle α based on the vertical direction of graphene layer 120 and detected.

[0058] Figure 5B The thickness of graphene layer 120 is shown as... Figure 5A The signal intensity of the photoelectron beam emitted from the silicon substrate 110. The interaction formula between the signal intensity of the photoelectron beam emitted from the silicon substrate 110 and the thickness t of the graphene layer 120 can be expressed as Equation 2 below.

[0059]

[0060] In equation 2, "I" Si "I" represents the signal intensity of the photoelectron beam emitted from the silicon substrate 110. Si0 "λ" represents the signal intensity measured from a photoelectron beam emitted from bulk silicon. Here, bulk silicon can be a silicon substrate with a large thickness. si,c "" represents the inelastic mean free path of the photoelectron beam generated from the silicon substrate 110 and transmitted through the graphene layer 120.

[0061] One method for calculating the thickness of the graphene layer 120 is to use the signal intensity of the photoelectron beam emitted from the graphene layer 120. Based on this method, the thickness t of the graphene layer 120 can be calculated using Equation 1 above and Equation 3 below. G .

[0062]

[0063] In equation 3, “λ EAL "I" is a value defined for measuring actual thickness and represents the effective attenuation length. Additionally, "I" C0"I" represents the signal intensity measured from the photoelectron beam emitted from bulk graphene. C "" indicates the signal intensity measured from the photoelectron beam emitted from graphene layer 120.

[0064] λ described in Equation 3 EAL The following calibration can be used to obtain and calculate the thickness of the graphene layer 120 relatively accurately.

[0065] As described above, while the absolute thickness may not be precisely calculated using the method of measuring thickness via XPS based on Equation 1, the ratio between different thicknesses can be accurately calculated. Specifically, in the absence of a detected measurement signal, the actual thickness can be precisely reduced to "0". Based on the method of measuring thickness using XPS, the offset can be "0". Therefore, the actual thickness t of the graphene layer 120 can be precisely calculated. G The thickness t of the graphene layer 120 calculated by XPS XPS The following equation 4 is formed between them.

[0066] t G =t XPS ×m (Equation 4)

[0067] In Equation 4, "m" represents the scaling factor used for XPS.

[0068] Furthermore, Equation 5 can be derived from Equation 4.

[0069] λ EAL =m×λ C,C (Equation 5)

[0070] While absolute thickness can be measured using transmission electron microscopy (TEM), the precise location of the interface can be difficult to pinpoint due to roughness or contamination. Therefore, the absolute thickness measured using TEM may contain some deviation.

[0071] Therefore, the actual thickness t of the graphene layer is 120. G The thickness t of graphene layer 120 calculated by TEM TEM The interaction between them forms an equation such as Equation 6 below.

[0072] t G =t TEM +c (Equation 6)

[0073] In Equation 6, "c" represents the offset with respect to TEM.

[0074] Furthermore, Equation 7 below can be formed from Equations 4 and 6.

[0075] t G =t XPS ×m=t MEM +c (Equation 7)

[0076] Based on Equation 7, the thickness t of the graphene layer 120, which can be calculated via XPS, is shown. XPS The thickness t of the graphene layer calculated by TEM TEM A linear relationship is established between them. Therefore, the conversion factor m for XPS can be determined via calibration from the linear relationship between the XPS measurement results and the TEM measurement results. Moreover, λ can be obtained from Equation 5 using the determined conversion factor m for XPS. EAL Furthermore, the thickness t of the graphene layer 120 can be calculated using Equation 3. G .

[0077] In the following, a method for calculating the thickness of a graphene layer 120 directly grown on a silicon substrate 110 using XPS will be described according to an example embodiment.

[0078] The method for calculating the thickness of the graphene layer 120 according to the example embodiment may include using the ratio between the signal intensity of the photoelectron beam emitted from the graphene layer 120 and the signal intensity of the photoelectron beam emitted from the silicon substrate 110. This method can be used both when no interface layer 130 is formed between the silicon substrate 110 and the graphene layer 120 and when the effect of the interface layer 130 is not reflected.

[0079] The thickness t of the graphene layer is 120. G It can be calculated using Equation 8 below, based on Equations 1 and 2 above. Here, it is based on λ described in Equation 1. c,c And the λ described in Equation 2 si,c Equation 8 is calculated by assuming that the values ​​are the same.

[0080]

[0081] in,

[0082]

[0083] “λ EAL "I" represents a value defined for measuring the actual thickness of the layer as described above, and indicates the effective attenuation length. Furthermore, "I" C0 "I" represents the signal intensity measured from the photoelectron beam emitted from bulk graphene. Si0 "I" indicates the signal strength measured from the photoelectron beam emitted from bulk silicon. Furthermore, "I" C"I" represents the signal intensity measured from the photoelectron beam emitted from graphene layer 120. Si "" indicates the signal intensity measured by the photoelectron beam emitted from the silicon substrate 110 and passing through the graphene layer 120.

[0084] The above describes how to obtain λ EAL The method is therefore omitted in its detailed description. The signal intensity I can be measured by calculating the photoelectron beam emitted from the bulk graphene. C0 The signal intensity I measured from the photoelectron beam emitted from bulk silicon Si0 The ratio is used to obtain R0. However, in this case, bulk graphene with a thickness equal to or greater than about 10 nm must be manufactured.

[0085] According to this embodiment, the signal intensity I of the photoelectron beam emitted from the silicon substrate 110 can be... Si The signal intensity I of the photoelectron beam emitted by the graphene layer 120 C The linear relationship formed between them yields R0.

[0086] In detail, Equation 9 below can be formed from Equations 1 and 2. Here, by assuming that...

[0087] The λ described in Equation 1 c,c And the λ described in Equation 2 si,c Use the same values ​​to calculate Equation 9.

[0088]

[0089] According to Equation 9, the signal intensity I of the photoelectron beam emitted from the silicon substrate 110 is identified. Si The signal intensity I of the photoelectron beam emitted from graphene layer 120 C A linear relationship can be formed between them.

[0090] Figure 6 This is a data graph showing the signal intensity I of the photoelectron beam emitted from the silicon substrate 110. Si The signal intensity I of the photoelectron beam emitted from graphene layer 120 (nanocrystalline graphene) C The measurement results were obtained by varying the thickness of a graphene layer (nanocrystalline graphene) 120 grown on a silicon substrate 110 within the range of about 1 nm to about 5 nm.

[0091] from Figure 6 The data curves shown in the figure identify the signal intensity I of the photoelectron beam emitted from the silicon substrate 110. Si The signal intensity I of the photoelectron beam emitted from graphene layer 120 C A linear relationship is formed between them. Here, by Figure 6The slope of the straight line formed by the data curves shown can correspond to -1 / R0 in Equation 9. Therefore, it can be determined by measuring the slope of the line formed by the data curves shown. Figure 6 The value of R0 is obtained by measuring the slope of the straight line formed by the data curve graph shown in the figure.

[0092] As shown above, according to the method for calculating the thickness of the graphene layer 120 according to this embodiment, the thickness of the graphene layer 120 can be measured by using the ratio between the signal intensity of the photoelectron beam emitted from the graphene layer 120 and the signal intensity of the photoelectron beam emitted from the silicon substrate 110, as shown in Equation 8.

[0093] According to another embodiment, another example of a method for calculating the thickness of the graphene layer 120 may include a method that reflects the effect of the interface layer 130 when an interface layer 130 is formed between the silicon substrate 110 and the graphene layer 120 in Equation 8 above. Here, the interface layer 130 may include silicon carbide, silicon carbide oxide, and silicon oxide as described above. Based on this method, the thickness t of the graphene layer 120 is... G It can be calculated using the following equation 10.

[0094]

[0095] In Equation 10, “K” is a correction value based on the effect of interface layer 130, and can be defined by Equation 11 below.

[0096]

[0097] in,

[0098]

[0099] “I SiC0 “I” SiOC ” and “I SiO0 "These are the signal intensities measured from photoelectron beams emitted from bulk silicon carbide, bulk silicon carbide, and bulk silicon oxide, respectively."

[0100] In Equation 10, as described above, the signal intensity I of the photoelectron beam emitted from the silicon substrate 110 can be obtained from... Si The signal intensity I of the photoelectron beam emitted from the graphene layer 120 C The linear relationship formed between them yields R0.

[0101] As described above, according to the method for calculating the thickness of graphene layer 120 according to the example embodiment, the thickness of graphene layer 120 directly grown on silicon substrate 110 can be calculated relatively accurately by using the ratio between the signal intensity of the photoelectron beam emitted from graphene layer 120 and the signal intensity of the photoelectron beam emitted from silicon substrate 110, the signal intensity being measured using XPS.

[0102] like Figure 1 As shown, an interface layer 130 can be formed between the silicon substrate 110 and the graphene layer 120. Furthermore, silicon carbide can be included in the interface layer 130. Here, silicon carbide is a material formed when silicon and carbon are bonded together. With increasing silicon carbide content, the adhesion between the silicon substrate 110 and the graphene layer 120 can be improved.

[0103] The measurement will be described below. Figure 1 The method for determining the amount of silicon carbide contained in the interface layer 130 formed between the silicon substrate 110 and the graphene layer 120 in the structure shown.

[0104] Figure 7 An example Si2p spectrum is shown using a photoelectron beam emitted from a silicon substrate 110 via XPS. Figure 7 In this context, SiC represents silicon carbide, SiOC represents silicon carbide, and SiO represents silicon oxide.

[0105] Reference Figure 7 In addition to the silicon peak, SiC, SiOC, and SiO peaks were also detected. Therefore, an interface layer 130 comprising SiC, SiOC, and SiO was identified between the silicon substrate 110 and the graphene layer 120.

[0106] The content of silicon carbide in interface layer 130 can be measured by the ratio of the composition of silicon carbide to the sum of the compositions of silicon carbide, silicon carbide oxide, and silicon oxide.

[0107] According to this exemplary embodiment, the content of silicon carbide included in the interface layer 130 can be determined by measuring... Figure 7 The signal intensity of silicon carbide, silicon carbide, and silicon oxide in the spectrum shown is used for measurement.

[0108] In detail, the content of silicon carbide included in the interface layer 130 can be measured by calculating the ratio of the area of ​​the silicon carbide peak to the sum of the areas of the silicon carbide peak, the silicon carbide peak, and the silicon oxide peak.

[0109] Figure 8The results show the content of silicon carbide and silicon oxide in the interface layer formed between the silicon substrate and the graphene layer when a graphene layer is grown on a silicon substrate by changing the process conditions in the PECVD process.

[0110] Figure 8 The silicon carbide and silicon oxide contents shown correspond to the results obtained by measuring the contents of silicon carbide and silicon oxide according to the above-described exemplary embodiment. Specifically, the silicon carbide content can be measured by calculating the ratio of the area of ​​the silicon carbide peak in the spectrum emitted from the silicon substrate to the sum of the areas of the silicon carbide peak, the silicon carbide peak, and the silicon oxide peak. Similarly, the silicon oxide content can be measured by calculating the ratio of the area of ​​the silicon oxide peak in the spectrum emitted from the silicon substrate to the sum of the areas of the silicon carbide peak, the silicon carbide peak, and the silicon oxide peak.

[0111] According to this embodiment, the content of silicon carbide included in the interface layer can be measured relatively accurately by measuring the signal intensity of silicon carbide, the signal intensity of silicon carbide oxide, and the signal intensity of silicon oxide in the spectrum emitted from the silicon substrate.

[0112] According to the above-described exemplary embodiments, the thickness of the graphene layer grown directly on the silicon substrate can be calculated relatively accurately using XPS by measuring the ratio between the signal intensity of the photoelectron beam emitted from the graphene layer and the signal intensity of the photoelectron beam emitted from the silicon substrate. Furthermore, the content of silicon carbide contained in the interface layer can be measured relatively accurately by measuring the signal intensities of silicon carbide, silicon carbide oxide, and silicon oxide in the spectrum emitted from the silicon substrate.

[0113] Figure 9 This is a flowchart illustrating a method for manufacturing a graphene device according to an example embodiment. Figures 10A to 10D This is a cross-sectional view illustrating a method for manufacturing a graphene device according to an example embodiment. Figures 11A to 11D This is a cross-sectional view illustrating a method for manufacturing a graphene device according to an example embodiment.

[0114] exist Figure 9 , Figures 10A to 10D as well as Figures 11A to 11D For ease of description, an example in which an interface layer 130 is formed between the graphene layer 120 and the substrate 110 is described; however, the exemplary embodiment is not limited to this. Figure 9 , Figures 10A to 10D as well as Figures 11A to 11D The example in the example can be modified to fabricate a graphene device without forming an interface layer 130 between the graphene layer 120 and the substrate 110.

[0115] Reference Figure 9 , Figure 10A and Figure 11A In operation S100, a substrate 110 (e.g., a silicon substrate) may be provided. Figure 10A As shown, spaced-apart doped regions 140' can be formed in the upper region of substrate 110 by implanting impurities into the substrate 110. (Refer to...) Figure 11A The substrate 110 may include an undoped region 140 or a doped region 140' below the upper surface of the substrate 110.

[0116] Reference Figure 9 , Figure 10B and Figure 11B In operation S110, a graphene layer 120 can be grown directly on the upper surface of the substrate 110. An interface layer 130 can be formed between the substrate 110 and the graphene layer 120, but in other embodiments, the interface layer 130 may not be formed.

[0117] Reference Figure 9 In operation S120, an XPS instrument can be used to measure the graphene layer 120 and / or the interface layer 130. For example, the thickness of the graphene layer 120 can be measured according to the embodiments discussed above to provide a measured thickness of the graphene layer 120. Furthermore, the content of the interface layer 130 (e.g., silicon carbide content) can be measured using an XPS instrument according to the embodiments discussed above to provide a measured content of the interface layer 130. In operation S130, the controller (not shown) of the XPS instrument can compare the measured thickness of the graphene layer 120 with a first threshold and a second threshold greater than the first threshold. The first and second thresholds can be reference values ​​corresponding to control limits for the thickness of the graphene layer 120, but are not limited thereto.

[0118] In operation S130, the controller (not shown) can compare the content of interface layer 130 with a third threshold and a fourth threshold greater than the third threshold. The third threshold and the fourth threshold can be reference values ​​corresponding to control limits for the content of interface layer 130 (e.g., the content of silicon carbide in interface layer 130), but are not limited thereto.

[0119] Reference Figure 9 , Figure 10C and Figure 11CIn response to the fact that the measured thickness of the graphene layer 120 and / or the measured content of the interface layer 130 in operation S130 have acceptable values, operation S140 can be performed. For example, in operation S130, the acceptable value for the measured thickness of the graphene layer 120 can be greater than or equal to a first threshold and less than or equal to a second threshold. Moreover, in operation S130, the acceptable value for the measured content of the interface layer 130 can be greater than or equal to a third threshold and less than or equal to a fourth threshold. However, the example implementation is not limited to this.

[0120] In operation S140, such as Figure 10C As shown, the interface layer 130 and the graphene layer 120 can be patterned to provide an interface pattern 1030 and a graphene pattern 1020 thereon, both of which cover at least a portion of the doped regions 140' and expose portions of the substrate 110 between the doped regions 140'. Figure 11C As shown, the interface layer 130 and the graphene layer 120 can be patterned to provide an interface pattern 1130 and a graphene pattern 1120 thereon, both of which cover at least a portion of the undoped region 140 or the doped region 140' and expose a portion of the substrate 110 surrounding the undoped region 140 or the doped region 140'.

[0121] Alternatively, refer to Figure 9 , Figure 10B and Figure 11B In response to unacceptable values ​​in the measured thickness of graphene layer 120 and / or the measured content of interface layer 130 during operation S130, operation S170 can be performed. Operation S170 can be referred to as a rework operation. In operation S170, graphene layer 120 and interface layer 130 can be removed. After removing graphene layer 120 and interface layer 130 in operation S170, the method can proceed to operation S110, where another graphene layer 120 can be grown on substrate 110, such as... Figure 10B and Figure 11B As shown. Another interface layer 130 may be formed between the graphene layer 120 and the substrate 100, or the interface layer 130 may be omitted in other embodiments. Next, after performing operation S110, the manufacturing method may proceed to operation S120.

[0122] Reference Figure 9 , Figure 10C and Figure 11C It can be formed according to operation S140 Figure 10C After the graphene pattern 1020 and interface pattern 1030 are formed and / or formed Figure 11C After the graphene pattern 1120 and interface pattern 1130 are formed, operation S150 is performed.

[0123] In operation S150, graphene patterns 1020 and 1120 and / or interface patterns 1030 and 1130 can be measured using an XPS instrument. Operation S150 can be similar to operation S120. For example, the thickness of graphene patterns 1020 and 1120 can be measured according to the embodiments discussed above to provide the measured thickness of graphene patterns 1020 and 1120. Moreover, the content of interface patterns 1030 and 1130 (e.g., silicon carbide content) can be measured using an XPS instrument according to the embodiments discussed above to provide the measured content of interface layer 130.

[0124] In operation S160, the controller (not shown) of the XPS instrument can compare the measured thicknesses of the graphene patterns 1020 and 1120 with a fifth threshold and a sixth threshold greater than the fifth threshold. The fifth and sixth thresholds can be reference values ​​corresponding to control limits for the thicknesses of the graphene patterns 1020 and 1120, and can be the same as or different from the first and second thresholds, respectively, but are not limited thereto.

[0125] In operation S160, the controller (not shown) can compare the contents of interface patterns 1030 and 1130 with a seventh threshold and an eighth threshold greater than the seventh threshold. The seventh threshold and the eighth threshold can be reference values ​​corresponding to control limit values ​​for the contents of interface patterns 1030 and 1130 (e.g., the content of silicon carbide in the interface patterns), and can be the same as or different from the third threshold and the fourth threshold, respectively, but are not limited thereto.

[0126] Reference Figure 9 , Figure 10C and Figure 11C In response to the measured thicknesses of graphene patterns 1020 and 1120 and / or the measured content of interface patterns 1030 and 1130 in operation S160 having acceptable values, one or more subsequent manufacturing processes can be performed in step S180. For example, in operation S160, the acceptable value for the measured thicknesses of graphene patterns 1020 and 1120 can be greater than or equal to a fifth threshold and less than or equal to a sixth threshold. Furthermore, in operation S160, the acceptable value for the measured content of interface patterns 1030 and 1130 can be greater than or equal to a seventh threshold and less than or equal to an eighth threshold. However, the example implementation is not limited to this.

[0127] In operation S180, such as Figure 10D As shown, a gate insulating layer (GIL) can be formed on the portion of substrate 110 exposed by the graphene pattern 1020 and interface pattern 1030. The GIL can comprise an insulating material such as silicon oxide or a high-k dielectric material (e.g., silicon nitride, hafnium oxide). Furthermore, as... Figure 10DAs shown, a source electrode S, a gate electrode G, and a drain electrode D can be formed on a substrate 110, wherein the source electrode S and the drain electrode D are spaced apart from each other on a graphene pattern 1020. The gate electrode G can be formed on a gate insulating layer GIL and can be spaced apart from the source electrode S and the drain electrode D. The source electrode S, the gate electrode G, and the drain electrode D can be formed of a conductive material such as a metal or a metal alloy.

[0128] Reference Figure 9 and Figure 11D In operation S180, an electrode EL can be formed on top of the graphene pattern 1120. The electrode EL can be formed of a conductive material such as a metal or metal alloy.

[0129] Alternatively, refer to Figure 9 , Figure 10C and Figure 11C Operation S170 can be performed in response to unacceptable values ​​in the measured thicknesses of graphene patterns 1020 and 1120 and / or the measured content of interface patterns 1030 and 1130 in operation S160. Operation S170 can be referred to as a rework operation. In operation S170, graphene patterns 1020 and 1120, as well as interface patterns 1030 and 1130, can be removed. After the removal of graphene patterns 1020 and 1120, as well as interface patterns 1030 and 1130, in operation S170, the method can proceed to operation S110, where another graphene layer 120 can be grown on substrate 110, such as... Figure 10B and Figure 11B As shown. Another interface layer 130 may be formed between the graphene layer 120 and the substrate 100, or in other embodiments, the interface layer 130 may not be formed. Next, after performing operation S110, the manufacturing method may proceed to operation S120.

[0130] In some example implementations, during operations S130 and S160, the XPS controller may be configured to compare the measured thickness of the graphene and / or interface layers and patterns with a reference value. The controller may include processing circuitry, which may include hardware such as logic circuitry; hardware / software combinations such as a processor executing software; or combinations thereof. For example, the processor may include, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), an application processor (AP) included in a neuromorphic device, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field-programmable gate array (FPGA), a system-on-a-chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit (ASIC), etc. The controller may include memory for storing the reference value, software, and instructions for controlling the operation of the XPS instrument discussed herein. The memory may be non-volatile memory, such as flash memory, phase-change random access memory (PRAM), magnetoresistive RAM (MRAM), resistive RAM (ReRAM), or ferroelectric RAM (FRAM), or volatile memory, such as static RAM (SRAM), dynamic RAM (DRAM), or synchronous DRAM (SDRAM).

[0131] In response to executing instructions from the software or commands received from the host, the controller can be converted into a dedicated controller for performing operations of the XPS instrument described herein, such as, but not limited to, calculating the thickness of graphene layer 120 and / or graphene patterns 1020 and 1120, measuring the content of interface layer 130 and / or interface patterns 1030 and 1130; and according to Figure 9 In operations S130 and S160, the measured thicknesses of graphene layers 120, graphene patterns 1020 and 1120 and / or the measured contents of interface layers 130 and interface patterns 1030 and 1130 are compared with reference values.

[0132] Although one or more embodiments have been described, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

[0133] This application claims the benefit of Korean Patent Application No. 10-2020-0063274, filed on May 26, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A method for measuring the thickness of a graphene layer directly grown on a silicon substrate using an X-ray photoelectron spectroscopy (XPS) instrument, the method comprising: Using the X-ray photoelectron spectroscopy instrument, in response to emitting X-ray radiation toward the graphene layer directly grown on the silicon substrate, a signal intensity is obtained from the graphene layer directly grown on the silicon substrate. as well as The thickness t of the graphene layer is calculated according to the following equation. G : ) in , , λ EAL It is the effective attenuation length. α is the detection angle of the X-ray photoelectron spectroscopy instrument. I co It is the signal intensity of the photoelectron beam emitted from bulk graphene. I sio It is the signal intensity of the photoelectron beam emitted from bulk silicon. I c It is the signal intensity of the photoelectron beam emitted from the graphene layer in response to X-ray radiation received by the graphene layer by the X-ray photoelectron spectrometer and detected by a sensor on the X-ray photoelectron spectrometer, and I si It is the signal intensity of the photoelectron beam emitted from the silicon substrate in response to X-ray radiation received by the silicon substrate by the X-ray photoelectron spectrometer and detected by a sensor on the X-ray photoelectron spectrometer, wherein The X-ray photoelectron spectroscopy instrument measures the signal intensity I of the photoelectron beam emitted from the silicon substrate. si and the signal intensity I of the photoelectron beam emitted from the graphene layer c The linear relationship between them yields R0.

2. The method according to claim 1, wherein, The graphene layer includes crystalline graphene or nanocrystalline graphene.

3. The method according to claim 1, wherein, The effective attenuation length is obtained through calibration based on the linear relationship between the results measured by transmission electron microscopy and the results measured by X-ray photoelectron spectroscopy.

4. The method according to claim 1, wherein, The bulk graphene has a thickness of 10 nm or more.

5. A method for measuring the thickness of a graphene layer using an X-ray photoelectron spectroscopy (XPS) instrument, wherein the graphene layer is grown directly on a silicon substrate, and an interface layer is formed between the silicon substrate and the graphene layer, the method comprising: Using the X-ray photoelectron spectroscopy instrument, in response to emitting X-ray radiation toward the graphene layer directly grown on the silicon substrate, a signal intensity is obtained from the graphene layer directly grown on the silicon substrate. as well as The thickness t of the graphene layer is calculated according to the following equation. G , in , λ EAL It is the effective attenuation length. α is the detection angle of the X-ray photoelectron spectroscopy instrument. I co It is the signal intensity of the photoelectron beam emitted from bulk graphene. I sio It is the signal intensity of the photoelectron beam emitted from bulk silicon. I c It is the signal intensity of the photoelectron beam emitted from the graphene layer in response to X-ray radiation received by the graphene layer by the X-ray photoelectron spectrometer and detected by a sensor on the X-ray photoelectron spectrometer, and I si It refers to the signal intensity of the photoelectron beam emitted from the silicon substrate in response to X-ray radiation received by the silicon substrate by the X-ray photoelectron spectrometer and detected by a sensor on the X-ray photoelectron spectrometer. K is a correction value based on the effect of the interface layer, where The X-ray photoelectron spectroscopy instrument measures the signal intensity I of the photoelectron beam emitted from the silicon substrate. si and the signal intensity I of the photoelectron beam emitted from the graphene layer c The linear relationship between them yields R0.

6. The method according to claim 5, wherein, The interface layer comprises silicon carbide, silicon carbide oxide, and silicon oxide.

7. The method according to claim 5, wherein, The graphene layer includes crystalline graphene or nanocrystalline graphene.

8. The method according to claim 5, wherein, The effective attenuation length is obtained through calibration based on the linear relationship between the results measured by transmission electron microscopy and the results measured by X-ray photoelectron spectroscopy.

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