Method and apparatus for manufacturing boron-containing diamond films.

Abstract

The objective is to provide a method for producing boron-containing diamond films (MPCVD method) that does not use boron-containing gas G1 as a boron-doping element source. [Solution] A method for manufacturing a boron-containing diamond film using the MPCVD method, in which a film-forming gas G0 is supplied from a film-forming gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to form a boron-containing diamond film on a substrate P0, characterized in that the film-forming gas G0 is supplied from the film-forming gas intake port S0 and a boron-containing quartz component 95 constituting a quartz injection head 90 is used as a boron-doping element source.

Description

[Technical Field]

[0001] This invention relates to a method and apparatus for manufacturing boron-containing diamond films. [Background technology]

[0002] Currently, high-quality boron-containing CVD diamond films are typically produced using the MPCVD method with dish-shaped and cylindrical chambers (see Figure 1 and Figure 11(A) for details on dish-shaped and cylindrical chambers). These conventional methods require introducing boron-containing gas G1 separately into the MPCVD equipment reaction chamber via a vent pipe, and boron-containing CVD diamond can be deposited by reacting it with other gases under set power, pressure, and other conditions. Boron-containing diamond film deposition requires a boron-doped element source, and currently, the main method for obtaining a boron-doped element source is to introduce boron-containing gas G1 into the reaction chamber of the MPCVD equipment via a vent pipe (Figure 1). Furthermore, the shortcomings of conventional technology are as follows: (1) The first drawback of the conventional technology is that boron-containing gas G1 is highly toxic and extremely harmful to human health, and at the same time is flammable and explosive, which poses a significant potential safety problem. In this invention, as an alternative method for obtaining a boron-doped element source, instead of introducing a boron-containing gas G1 into the MPCVD equipment reaction chamber via a vent pipe, a method is adopted in which a boron-containing quartz component 95 is placed on a film deposition stage P01 in the center of the chamber, and the upper part of the boron-containing quartz component is adjacent to the upper part of the chamber, thereby uniformly releasing the boron-doped element and solving the first problem of this invention (Figure 2). Boron-containing gas G1 contains borane and is toxic, but boron-containing quartz component 95 is a solid, and the borons released from the solid are not toxic, or have very low toxicity. (2) The second drawback of the conventional technology is that when boron-containing gas G1 is introduced into the chamber via a vent pipe, it causes an unbalanced distribution of boron-containing gas G1, which affects the quality of the boron-containing diamond film deposition. In order to overcome the second drawback of the prior art, the inventors have come up with the following two solutions (characteristic constituent elements). (2-1) First characteristic element In this invention, by using a method (means) for introducing boron using a boron-containing quartz component 95 (solid material) as an alternative method (means) to the conventional boron gas inhalation method (mouth), which is a boron-doped element source, we were able to achieve a remarkable effect of releasing the boron-doped element more uniformly than with the boron gas inhalation method (mouth). This is because the boron distribution in the boron-containing quartz component 95 is very uniform, allowing the boron-containing quartz component to release boron uniformly (solving the second problem of the present invention described below). (2-2) Second characteristic element In this invention, in addition to the first characteristic constituent element, the remarkable effects of the second characteristic constituent element were achieved as follows. The quartz injection head 90, consisting of boron-containing quartz components 95, employs a method for uniformly releasing boron-doped elements through a large number of holes and their regular arrangement (for example, the boron-containing diamond film deposition method described in any of claims 4 to 6; the boron-containing diamond film deposition apparatus 100 described in any of claims 10 to 12), thereby solving the second problem of the present invention described below. [Disclosure of the Invention]

[0003] In light of the shortcomings of the prior art, the inventor conducted diligent research and, as a result, completed the present invention. [Prior art documents] [Patent Documents]

[0004] Regarding the boron-containing diamond film formation method (manufacturing apparatus) related to the present invention, a FI and keyword search was performed, but no documents describing inventions similar to the present invention (the invention described in any of claims 1 to 12) were found; therefore, the description of patent documents is omitted. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] ○The first problem that the present invention aims to solve The first problem that this invention aims to solve is, The objective is to provide a method (manufacturing means) for producing boron-containing diamond films using the MPCVD method, without using boron-containing gas G1 as the boron-doping element source. ○The second problem that the present invention aims to solve The second problem that this invention aims to solve is, The objective is to provide a method (manufacturing means) for manufacturing boron-containing diamond films that overcomes the drawback of conventional technology, where introducing boron-containing gas G1 into the chamber via a vent pipe causes an unbalanced distribution of boron-containing gas G1, affecting the quality of the boron-containing diamond film. [Means for solving the problem]

[0006] The means for solving the problem are the inventions described in each claim of the [claims] of this application. To resolve any ambiguities regarding the interpretation of terms in the claims, specifications, drawings, etc., the following explanations of terms are provided. <Explanation of Terms> ******************************************************* <(Regarding the right-handed XYZ coordinate system)> In this invention, the coordinate system adopted is the right-handed XYZ coordinate system. The XYZ coordinate system is defined, in principle, as follows (Figure 9). The X direction refers to the direction from the front to the back (horizontal direction). The Y direction refers to the vertical direction (anti-gravity direction). The Z direction refers to the direction from the left side to the right side (horizontal direction) toward X. With the center of gravity of the object (for example, a boron-containing diamond film-forming apparatus) as the center, the side closer to the center is defined as the inner side, and the side farther from the center is defined as the outer side. ******************************************************* <Relationship between the XYZ coordinate system and six views (front view, rear view, top view, bottom view, left side view, right side view)> Hereinafter, the relationship between the XYZ coordinate system and the six views will be described. Already, in <(right-handed) XYZ coordinate system>, the definition of the (right-handed) XYZ coordinate system has been given (Figure 9). In such an XYZ coordinate system, as follows, the six views (front view, rear view, top view, bottom view, left side view, right side view) are defined (Figure 9) In the six views, first, the front view is defined. In the object, the view that an observer on the front side observes the object on the rear side is defined as the front view (the direction from the front side of the paper to the back side of the paper is the X direction). Then, the rear view is defined. The view that an observer on the rear side observes the object on the front side is defined as the rear view (the direction from the front side of the paper to the back side of the paper is the -X direction). Next, the top view is defined. The view that an observer on the upper side observes the object on the lower side is defined as the top view (the direction from the front side of the paper to the back side of the paper is the -Y direction). Then, the bottom view is defined. The view that an observer on the lower side observes the object on the upper side is defined as the bottom view (the direction from the front side of the paper to the back side of the paper is the Y direction). Next, the left side view is defined. The view that an observer on the left side observes the object on the right side is defined as the left side view (the direction from the front side of the paper to the back side of the paper is the Z direction). Then, the right side view is defined. The view that an observer on the right side observes the object on the left side is defined as the right side view (the direction from the front side of the paper to the back side of the paper is the -Z direction). Here, A frontal perspective view is a diagram that shows an object located behind an observer, as seen from the upper right. Furthermore, once the six views (front view, rear view, top view, bottom view, left side view, and right side view) are identified, the XYZ coordinate system defined above can be uniquely determined for each of the identified views. ******************************************************* ● Boron-containing diamond (also called boron-doped diamond) BD refers to diamond in which some of the carbon atoms that make up the diamond have been replaced with boron atoms. Doping diamond with boron affects its conductivity. At low doping concentrations, the diamond remains an insulator, but as the doping concentration increases, it changes from a semiconductor to a conductor. It has been reported that at high doping concentrations of approximately 3%, the diamond exhibits superconductivity at extremely low temperatures. ● The boron-containing diamond film deposition manufacturing method (manufacturing apparatus 100) refers to the MPCVD method (manufacturing apparatus 99) which uses the MPCVD method to form a thin film of boron-containing diamond (boron-doped diamond) BD (deposition of boron-containing diamond BD). ● MPCVD (Microwave Plasma CVD) is a method of synthesizing diamond on a predetermined substrate by using microwave discharge to separate gas molecules into ions and electrons (into a plasma state) with the energy of electrons. ●MPCVD apparatus 99 refers to an apparatus (conventional technology) that uses the above MPCVD method (microwave plasma CVD method) to deposit boron-containing diamond BD onto a substrate P0. ●Film deposition refers to the process of forming a thin film on the surface of an object. ●Regarding the film-forming gas G0, in this invention, hydrogen is used as the carrier gas and methane is used as the working gas, with methane making up 6-12% of the hydrogen. Nitrogen, oxygen, or borane can also be added in ppm proportions. ●The film-forming gas intake port S0 refers to the intake port for taking in the film-forming gas G0. ●Boron-containing gas G1 generally refers to various boranes (boranes are compounds of boron and hydrogen, and are a general term for hydrides of boron), such as BH3 and B2H6. ● Chamber CB refers to the space inside the apparatus of this invention. In this invention, the chamber consists of two chambers. Specifically, chamber CB is composed of a lower dish-shaped chamber CB2 and an upper cylinder-shaped chamber CB1 (Figures 1, 2, and Figure 11(A)). ● In this invention, boron doping refers to replacing (doping) some of the carbon atoms that make up diamond with boron atoms. ● A boron-doped element source is a source that releases boron to replace some of the carbon atoms that make up diamond with boron atoms. In this invention, a boron-doped element source refers to a quartz component that uniformly contains boron to replace some of the carbon atoms that make up diamond with boron atoms. A boron-doped element source refers to a boron-containing gas G1 that, in conventional technology, replaces some of the carbon atoms that make up diamond with boron atoms. In this invention, the term refers to a quartz component containing boron, which replaces some of the carbon atoms that make up diamond with boron atoms. ●Substrate P0 refers to a plate used to form a boron-containing diamond thin film. ●The deposition stage P01 refers to the stage on which the substrate P0 is placed. ●The quartz spray head 90 is an airflow spray head (shower head) composed of a boron-containing quartz component 95 (solid material) that sprays boron-containing gas G1. ●Boron-containing quartz component 95 is a solid component composed of boron and quartz that uniformly releases boron, and there are two types as follows: (First type) The first type is traditional boron-containing quartz glass (solid material), also known as borax glass (borosilicate glass). Borax glass (borosilicate glass) is a type of glass made by mixing 5% or more boric acid with the molten glass to increase its softening temperature and hardness. It is a representative example of heat-resistant and hard glass. It has a low coefficient of thermal expansion, making it more resistant to thermal shock than ordinary glass. Due to its excellent heat and chemical resistance, it is used in scientific and chemical equipment and kitchenware. (Second type) The second method involves plating solid boron onto the surface of a quartz component using a plating-like technique. Plating methods include chemical formation methods for boron thin films such as PECVD (Plasma Enhanced Chemical Vapor Deposition), MOCVD (Metal Organic Chemical Vapor Deposition), PVD (Physical Vapor Deposition, a surface treatment method also known as physical vapor deposition), and electrical plating. ● Exhaust gas G2 refers to exhaust gas that is no longer needed for the synthesis of boron-containing diamond BD. ● Exhaust port E refers to the outlet for discharging exhaust gas G2, which is no longer needed for the synthesis of boron-containing diamond BD, outside the chamber CB. ●Gap 10 refers to the open, planar space between the top of the quartz injection head 90 and the top of the chamber CB. ●A hole refers to a number of holes (or one of many holes) that are regularly arranged in the quartz injection head 90 (Figures 4-8, Figure 10). ●The bore diameter d (cm) refers to the bore diameter (cm) of the hole in the quartz injection head 90 (Figures 7-8, 10, and 1). ●The bore position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90 (Figures 7-8, Figure 10). ●const. stands for constant (cm 2 It refers to ,cm. ●C1 is a constant (cm 2 ) refers to. ● Incidence angle θ... This refers to the angle (°) that the jet stream makes with respect to the vertical direction (Y direction) (Figures 8 and 10). ●C2 refers to the constant (cm). <Differences between the prior art and the present invention (summary)> 1. The common features of the prior art and the present invention are as follows: Regarding the commonalities between the prior art and the present invention, firstly, both technologies are MPCVD methods for depositing high-quality boron-containing CVD diamond films. Secondly, the quality and applications of the boron-containing diamond BDs deposited by the two technologies are basically the same. Thirdly, except for the method of introducing boron, the methods of introducing other raw material gases are the same. 2. Differences between the prior art and the present invention The differences between the prior art and the present invention are: Firstly, the boron-doped element source was changed from boron-containing gas G1 to boron-containing quartz components. Secondly, the vent pipes for boron-containing gas that were introduced into the structure of the existing dish-shaped and cylinder-shaped chambers were removed, and boron-containing quartz components were added to the chambers. The first major difference is that the boron-doped element source has been changed from boron gas to boron-containing quartz components, and the second difference is that boron-containing quartz components have been added inside the chamber. 3. The function of the present invention This invention uses a novel method to provide a boron source by placing boron-containing quartz components inside the chamber of the manufacturing equipment, thereby preventing the use of toxic and harmful gases during production. As shown in Figure 1, in MPCVD, the quartz injection head is placed on the deposition stage P01 located in the center of the chamber. The top of the injection head is adjacent to the top of the chamber, with a gap of less than 1 mm. The lower support is in a predetermined position on the deposition stage. The structure of a typical boron-containing quartz injection head is shown in Figure 2. Multiple designs are possible for the pores of the injection head. One is to increase the pore diameter in proportion to the radius of the injection head so that the gas flow rate does not change fundamentally with respect to the head radius. Another is to change the direction of the pores from straight to proportion to the radius so that the airflow is stably distributed. By adjusting the boron content of the quartz injection head according to the amount of boron doping in the diamond, various types of boron-doped diamond films can be achieved. 4. Effects of the present invention By adding boron-containing quartz components to the existing dish-shaped and cylindrical chamber structures, a boron-doped element source is created in the MPCVD diamond deposition process, followed by the deposition of boron-containing diamond films. This method avoids the use of conventional boron-containing toxic gases, and the quartz components allow for a regular response to gas diffusion, resulting in uniform boron-containing diamond film deposition and effective improvement of diamond film quality. <Method for calculating airflow (plasma flow) (Part 1)> To clarify the regularity of the "numerous regularly arranged holes" in the quartz injection head 90, the following calculations were performed (see Figures 4 to 7). n; Number of holes (number of holes in a circle with radius r and circumference 2πr (cm)) r; Radius (cm) from the center O of multiple holes to the position of each hole. d; Hole diameter (cm) S; Range of fluid ejected from the hole (cm) ∝; a symbol meaning proportionality const.; constant (cm 2 ,cm) C1;Constant(cm 2 ) C2. Constant (cm) Here, the cross-sectional area of the hole (cm 2 ) = (π / 4)d 2 , and the circumference of a circle with radius r (cm) = 2πr Total area in the circumference of the hole (cm 2 ) = (π / 4)d 2 ×n Therefore, n ∝ 2πr / d ∝ r / d ∴ Total area in the circumference of the hole (cm 2 ) = (π / 4)d 2 ×n ∝ (π / 4)d 2 ×r / d = (π / 4)dr ∝ dr... Equation (1-1) Also, from another perspective Total area in the circumference of the hole (cm 2 ) = 2πrS ∝ rS... Equation (1-2) Combining Equation (1-1) and Equation (1-2), we obtain Equation (1-3). [[ID=3�]]dr ∝ rS (i.e., d ∝ S)... Equation (1-3) (1) In Equation (1-1), if the total area in the circumference of the hole (cm 2 ) = const., then we obtain Equation (A). dr = const. = C1 That is d == C1 / r... Equation (A) On the other hand, in Equation (1-2), if the total area in the circumference of the hole (cm 2 ) = const., then we obtain Equation (A’). rS = const. (S = const. / r)... Equation (A’) (2) In Equation (1-3) (d ∝ S), when d = const., we obtain S = const. Here d = const.... Equation (B) S = const.... Equation (B’) Therefore Equation (A) represents the cases of claims 4 and 10 Equation (B) represents the cases of claims 5 and 11 <Method for calculating airflow (plasma flow) (Part 2)> To determine the regularity of the "numerous regularly arranged holes" in the quartz injection head 90, the following calculations were performed (see Figures 4-8 and 10). θ; Incidence angle of the jet stream (°) n; number of holes r; Radius (cm) from the center O of multiple holes to the position of each hole. d; Hole diameter (cm)... Diameter of the cross-sectional area of ​​the hole (cm) const.; constant (cm 2 ) C2.; Constant (cm) Here, the cross-sectional area of ​​the hole (cm²) 2 )=(π / 4)d 2 The circumference of a circle with radius r (cm) = 2πr Total area along the circumference of the hole (cm²) 2 )=(π / 4)d 2 ×n The fluid flow rate in the direction of gravity (-Y direction) is (π / 4)d 2 ×n × cos(θ) Also, n∝2πr / d∝r / d Therefore, the fluid flow rate in the direction of gravity (-Y direction) is (π / 4)d 2 ×COS(θ)×n∝(π / 4)d 2 ×COS(θ)×r / d =(π / 4)dr×COS(θ)∝dr×COS(θ)= const.…(1-3) formula In equation (1-3), if r = const., d × COS(θ) = C² ∴d=C2 / COS(θ) …(C) formula This is true. Formula (C) represents the case of claims 6 and 12. In Figures 8 and 10, the jet is ejected in a downward-right direction relative to the plane of the paper (within the YZ plane of the XYZ coordinate system), so no rotational force acts on the fluid, and therefore no swirling flow occurs. However, if the incidence angle θ(°) of the jet has an angle θ' with respect to the YZ plane, a rotational force acts on the fluid, and a swirling flow occurs. <Why the regularly arranged numerous holes in the quartz injection head 90 are a characteristic feature of the design> (1) When the regularly arranged numerous holes (characteristic constituent element) of the quartz injection head 90 are not introduced. Since there are no distinctive constituent elements that control airflow, the flow of air can be likened to flow in a pipe. Because there are no regularly arranged holes, the airflow remains non-swirling (continues to swirl), and since the airflow is relatively concentrated in the center, the amount of gas flowing in is greater in the center and smaller at the walls, resulting in an unbalanced flow. This follows the fundamental properties of fluids: the fluid velocity in a pipe is fastest in the center of the pipe and becomes zero near the walls. Therefore, the gas flow velocity (or flow rate) differs across the same cross-section of the pipe, with the velocity being faster (higher flow rate) in the center and slower (lower flow rate) near the walls. (2) Introduction of numerous regularly arranged holes in the quartz injection head 90 To correct the unbalanced flow described above, the inventor conceived the present invention to equalize the gas inflow by changing the area of ​​the diameter (size and number of diameters) depending on the location of the flow. In this case, when a showerhead (quartz jet head 90) is added to the fluid cross-section, the gas flow rate at each location is directly related to the area and number of channels (holes). If the hole size is the same, reducing the number of holes in the center may obstruct the gas flow in the central area. It is said that reducing the gas flow in the central region causes the gas flow to shift towards the edges, promoting a more uniform flow. The same effect can be obtained by keeping the number of holes the same and reducing the number of holes in the center. The holes described above are generally vertical, but if the direction of the holes is inclined to some extent, and the direction of that inclination coincides with the direction of the airflow (gas flow), the airflow can rotate and form a tornado-like effect. A stable airflow can be maintained (see Figures 8 and 10). The means for solving the problem are the inventions described in each claim of the present patent application, and the specific means for solving the problem are as follows. ○First invention (the invention described in claim 1) The first invention (the invention described in claim 1) for solving the above problem is, A method for manufacturing a boron-containing diamond film using the MPCVD method, in which a film deposition gas G0 is supplied from a film deposition gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to deposit a boron-containing diamond BD on a substrate P0, characterized in that the film deposition gas G0 is supplied from the film deposition gas intake port S0 and a boron-containing quartz component 95 constituting the quartz injection head 90 is used as the boron-doping element source. ○Second invention (the invention described in claim 2) The second invention (the invention described in claim 2) for solving the above problem is: The method for producing a boron-containing diamond film according to claim 1 is characterized in that the film-forming gas G0 consists of a mixed gas of methane and hydrogen. ○ Third invention (the invention described in claim 3) A third invention (the invention described in claim 3) for solving the above problems is: A method for manufacturing a boron-containing diamond film according to either of claims 1 or 2, characterized in that a quartz injection head 90 made of boron-containing quartz components 95 is placed on a film deposition stage P01 located in the center of a chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. ○Fourth invention (the invention described in claim 4) The fourth invention (the invention described in claim 4) for solving the above problems is: A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (A). d = C1 / r ... (Equation A) Here, the bore position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. C1 is a constant (cm 2 ) refers to. ○ Fifth invention (the invention described in claim 5) A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B). d=const.……(B) formula Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. "Const." refers to a constant (cm). ○The sixth invention (the invention described in claim 6) The sixth invention (the invention described in claim 6) for solving the above problems is: A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C). d = C² / cos(θ) ... (C) equation Here, the bore position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). C² refers to the constant (cm). ○The seventh invention (the invention described in claim 7) The seventh invention (the invention described in claim 7) for solving the above problems is: A boron-containing diamond film deposition manufacturing apparatus 100 that utilizes an MPCVD apparatus 99 for depositing boron-containing diamond BD on a substrate P0, is characterized by comprising a film deposition gas intake port S0 for supplying film deposition gas G0, an exhaust port E for discharging exhaust gas G2, and a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source. ○The eighth invention (the invention described in claim 8) The eighth invention (the invention described in claim 8) for solving the above problems is: The boron-containing diamond film deposition apparatus 100 according to claim 7 is characterized in that the film deposition gas G0 consists of a mixed gas of methane gas and hydrogen gas. ○Ninth invention (the invention described in claim 9) The ninth invention (the invention described in claim 9) for solving the above problems is: The boron-containing diamond film deposition apparatus 100 according to claim 7 is characterized in that a quartz injection head 90, consisting of boron-containing quartz components 95, is installed on a film deposition stage P01 located in the center of the chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. ○The tenth invention (the invention described in claim 10) The tenth invention (the invention described in claim 10) for solving the above problems is: A boron-containing diamond film manufacturing apparatus 100 according to any one of 7 to 9, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (A). d = C1 / r ... (Equation A) Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. C1 is a constant (cm 2 ) refers to. ○The 11th invention (the invention described in claim 11) The eleventh invention (the invention described in claim 11) for solving the above problems is: A boron-containing diamond film deposition apparatus 100 according to any one of 7 to 9, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B). d=const.……(B) formula Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. "Const." refers to a constant (cm). ○The 12th invention (the invention described in claim 12) The twelfth invention (the invention described in claim 12) for solving the above problems is: A boron-containing diamond film production apparatus 100 according to any one of 7 to 9, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C). d = C² / cos(θ) ... (C) equation Here, the bore position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). "Const." refers to a constant (cm). [Effects of the Invention]

[0007] The boron-containing diamond film manufacturing method according to the present invention is composed of the characteristic constituent elements described above, and produces the following effects unique to the present invention, corresponding to the characteristic constituent elements. Furthermore, a boron-containing diamond film manufacturing method, composed of the characteristic constituent elements described above according to each of the above inventions, was able to fully resolve the problems of the present invention. ○ Effects of the first invention According to the first invention, In a boron-containing diamond film manufacturing method utilizing the MPCVD method, in which a film-forming gas G0 is supplied from a film-forming gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to form a boron-containing diamond BD on a substrate P0, the first and second problems that the present invention aims to solve can be achieved by the characteristic configuration requirements of supplying the film-forming gas G0 from the film-forming gas intake port S0 and using a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source, and remarkable effects that are unpredictable to those skilled in the art can be achieved. ○ Effects of the second invention According to the second invention, The distinctive constituent requirement that the film-forming gas G0 consists of a mixed gas of methane and hydrogen makes it possible to achieve the first and second problems that the present invention aims to solve, and to produce remarkable effects that are unpredictable to those skilled in the art. ○ Effects of the third invention According to the third invention, The quartz injection head 90, consisting of boron-containing quartz components 95, is installed on a film deposition stage P01 located in the center of the chamber CB. The upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. These characteristic configuration requirements allow the first and second problems that the present invention aims to solve to be achieved, resulting in remarkable effects that are unpredictable to those skilled in the art. ○ Effects of the fourth invention According to the fourth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy equation (A) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. ○ Effects of the fifth invention According to the fifth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. ○ Effects of the sixth invention According to the sixth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. ○ Effects of the seventh invention According to the seventh invention, In a boron-containing diamond film deposition manufacturing apparatus 100 that utilizes an MPCVD apparatus 99 for depositing boron-containing diamond BD on a substrate P0, the apparatus is characterized by having a film deposition gas intake port S0 for supplying film deposition gas G0 and a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source. This characteristic configuration makes it possible to solve the first and second problems that the present invention aims to solve, and to achieve remarkable effects that are unpredictable to those skilled in the art. ○Effects of the 8th Invention According to the eighth invention, The distinctive constituent requirement that the film-forming gas G0 consists of a mixed gas of methane and hydrogen makes it possible to achieve the first and second problems that the present invention aims to solve, and to produce remarkable effects that are unpredictable to those skilled in the art. ○ Effects of the 9th Invention According to the ninth invention, The quartz injection head 90, consisting of boron-containing quartz components 95, is installed on a film deposition stage P01 located in the center of the chamber CB. The upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. These characteristic configuration requirements allow the first and second problems that the present invention aims to solve to be achieved, resulting in remarkable effects that are unpredictable to those skilled in the art. ○ Effects of the 10th Invention According to the tenth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy equation (A) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. ○ Effects of the 11th Invention According to the 11th invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. ○ Effects of the 12th Invention According to the twelfth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. [Best Mode for Carrying Out the Invention]

[0008] The best embodiment of the boron-containing diamond film manufacturing method according to the present invention will be described below with reference to the drawings. [Figure 1] Figure 1 shows a front view of the prior art. [Figure 2] Figure 2 shows a front view of the present invention. [Figure 3] Figure 3 shows a front view of the boron-containing quartz component 95. (A) Figure shows a front view of the first type of boron-containing quartz component 95. (B) Figure shows a front view of the second type of boron-containing quartz component 95. [Figure 4] Figure 4 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (A). Figure 4(A) shows a plan view of the quartz injection head 90. Figure 4(B) shows a cross-sectional view taken along the arrow AA. Figure 4(C) shows a front view of the quartz injection head 90. Figure 4(D) shows a perspective view of the quartz injection head 90. [Figure 5] Figure 5 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (B). Figure 5(A) shows a plan view of the quartz injection head 90. Figure 5(B) is missing. Figure 5(C) shows a cross-sectional view taken along the BB arrow. Figure 5(D) shows a perspective view of the quartz injection head 90. [Figure 6] Figure 6 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (C). Figure 6(A) shows a plan view of the quartz injection head 90. Figure 6(B) is missing. Figure 6(C) shows a cross-sectional view taken along the BB arrow. Figure 6(D) shows a perspective view of the quartz injection head 90. [Figure 7] Figure 7 is a reference diagram in the calculation method (part 1) for airflow (plasma flow). [Figure 8] Figure 8 is a reference diagram in the calculation method for airflow (plasma flow) (Part 2). (A) Figure shows a perspective view in the calculation method for airflow (plasma flow) (Part 2). (B) Figure shows a cross-sectional view when a fluid flows into a hole in the boron-containing quartz component 95 at an incidence angle θ (°). (C) Figure shows the view from arrow AA in Figure (B), where the cross-sectional area of ​​the airflow = cross-sectional area of ​​the hole = (π / 4)d 2 (cm) [Figure 9] Figure 9 shows the relationship between the XYZ coordinate system and the six-view drawings (front view, rear view, top view, bottom view, left side view, and right side view). [Figure 10] Figure 10(A) is a perspective view of the quartz injection head 90. Figure 10(B) is a front cross-sectional view of the boron-containing quartz component 95. (B) The upper part of the figure shows a front cross-sectional view of the boron-containing quartz component 95 that satisfies equation (A). The middle section of Figure (B) shows a front cross-sectional view of the boron-containing quartz component 95 that satisfies equation (B). (B) The lower part of the figure shows a front cross-sectional view of a boron-containing quartz component 95 that satisfies equation (C). [Figure 11] Figure 11(A) is a front view of the invention showing the area of ​​chamber CB (the area with thick diagonal lines). Figure 11(B) is an enlarged view of the front view of the invention showing the area around the gap 10 and the quartz injection head 90. The boron-containing diamond film manufacturing method according to the present invention will be described below with reference to the drawings. 11111************************************************** In the boron-containing diamond film production method of the present invention, A method for manufacturing a boron-containing diamond film using the MPCVD method, in which a film deposition gas G0 is supplied from a film deposition gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to deposit a boron-containing diamond BD on a substrate P0, is disclosed, characterized in that the film deposition gas G0 is supplied from the film deposition gas intake port S0 and a boron-containing quartz component 95 constituting a quartz injection head 90 is used as a boron-doping element source. ○ Effects of the first invention According to the first invention, In a boron-containing diamond film manufacturing method utilizing the MPCVD method, in which a film-forming gas G0 is supplied from a film-forming gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to form a boron-containing diamond BD on a substrate P0, the first and second problems that the present invention aims to solve can be achieved by the characteristic configuration requirements of supplying the film-forming gas G0 from the film-forming gas intake port S0 and using a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source, and remarkable effects that are unpredictable to those skilled in the art can be achieved. 22222************************************************** In the above method for producing boron-containing diamond films, A method for producing a boron-containing diamond film according to claim 1 is disclosed, characterized in that the film-forming gas G0 consists of a mixed gas of methane and hydrogen. ○ Effects of the second invention According to the second invention, The distinctive constituent requirement that the film-forming gas G0 consists of a mixed gas of methane and hydrogen makes it possible to achieve the first and second problems that the present invention aims to solve, and to produce remarkable effects that are unpredictable to those skilled in the art. 33333**************************************************** In the above method for producing boron-containing diamond films, A method for manufacturing a boron-containing diamond film is disclosed, characterized in that a quartz injection head 90, consisting of a boron-containing quartz component 95, is placed on a film deposition stage P01 located in the center of a chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. ○ Effects of the third invention According to the third invention, The quartz injection head 90, consisting of boron-containing quartz components 95, is installed on a film deposition stage P01 located in the center of the chamber CB. The upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. These characteristic configuration requirements allow the first and second problems that the present invention aims to solve to be achieved, resulting in remarkable effects that are unpredictable to those skilled in the art. 44444************************************************** In the above method for producing boron-containing diamond films, A method for producing a boron-containing diamond film according to any one of claims 1 to 3 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (A). d = C1 / r ... (Equation A) Here, the bore position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. C1 is a constant (cm 2 ) refers to. ○ Effects of the fourth invention According to the fourth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy equation (A) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. 55555************************************************** In the above method for producing boron-containing diamond films, A method for producing a boron-containing diamond film according to any one of claims 1 to 3 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B). d=const.……(B) formula Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. "Const." refers to a constant (cm). ○ Effects of the fifth invention According to the fifth invention, The distinctive structural requirement that the diameter d (cm) and diameter position r (cm) of the hole in the quartz injection head 90 satisfy formula (B) makes it possible to achieve the first and second problems that the present invention aims to solve, and to produce remarkable effects that are unpredictable to those skilled in the art. 66666************************************************** In the above method for producing boron-containing diamond films, A method for producing a boron-containing diamond film according to any one of claims 1 to 3 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C). d = C² / cos(θ) ... (C) equation Here, the bore position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). "Const." refers to a constant (cm). ○ Effects of the sixth invention According to the sixth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C) allows the first and second problems that the present invention aims to solve to be achieved, resulting in remarkable effects that are unpredictable to those skilled in the art. 77777************************************************** In the boron-containing diamond film deposition apparatus 100 of the present invention, A boron-containing diamond film deposition manufacturing apparatus 100 is disclosed, which utilizes an MPCVD apparatus 99 for depositing boron-containing diamond BD on a substrate P0, and is characterized by comprising a film deposition gas intake port S0 for supplying film deposition gas G0 and a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source. ○ Effects of the seventh invention According to the seventh invention, In a boron-containing diamond film deposition manufacturing apparatus 100 that utilizes an MPCVD apparatus 99 for depositing boron-containing diamond BD on a substrate P0, the apparatus is characterized by having a film deposition gas intake port S0 for supplying film deposition gas G0 and a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source. This characteristic configuration makes it possible to solve the first and second problems that the present invention aims to solve, and to achieve remarkable effects that are unpredictable to those skilled in the art. 88888************************************************** In the above method for producing boron-containing diamond films, A boron-containing diamond film deposition apparatus 100 is disclosed according to claim 7, characterized in that the film deposition gas G0 consists of a mixed gas of methane gas and hydrogen gas. ○Effects of the 8th Invention According to the eighth invention, The distinctive constituent requirement that the film-forming gas G0 consists of a mixed gas of methane and hydrogen makes it possible to achieve the first and second problems that the present invention aims to solve, and to produce remarkable effects that are unpredictable to those skilled in the art. 99999**************************************************** In the above method for producing boron-containing diamond films, A boron-containing diamond film deposition apparatus 100 is disclosed according to claim 7, characterized in that a quartz injection head 90, consisting of a boron-containing quartz component 95, is installed on a deposition stage P01 located in the center of the chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. ○ Effects of the 9th Invention According to the ninth invention, The quartz injection head 90, consisting of boron-containing quartz components 95, is installed on a film deposition stage P01 located in the center of the chamber CB. The upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm. These characteristic configuration requirements allow the first and second problems that the present invention aims to solve to be achieved, resulting in remarkable effects that are unpredictable to those skilled in the art. 101010************************************************ In the above method for producing boron-containing diamond films, A boron-containing diamond film deposition apparatus 100 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (A). d = C1 / r ... (Equation A) Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. C1 is a constant (cm 2 ) refers to. ○ Effects of the 10th Invention According to the tenth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy equation (A) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. 111111************************************************ In the above method for producing boron-containing diamond films, A boron-containing diamond film deposition apparatus 100 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B). d=const.……(B) formula Here, the bore position r refers to the distance (cm) from the center of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) in the quartz injection head 90. "Const." refers to a constant (cm). ○ Effects of the 11th Invention According to the 11th invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (B) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. 121212************************************************ In the above method for producing boron-containing diamond films, A boron-containing diamond film deposition apparatus 100 is disclosed, characterized in that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C). d = C² / cos(θ) ... (C) equation Here, the bore position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a bore diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). "Const." refers to a constant (cm). ○ Effects of the 12th Invention According to the twelfth invention, The distinctive structural requirement that the bore diameter d (cm) and bore position r (cm) of the quartz injection head 90 satisfy formula (C) allows the present invention to achieve the first and second problems it aims to solve, resulting in remarkable effects unpredictable to those skilled in the art. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows a front view of the conventional technology. [Figure 2] Figure 2 shows a front view of the present invention. [Figure 3] Figure 3 shows a front view of the boron-containing quartz component 95. (A) shows a front view of the first type of boron-containing quartz component 95. (B) shows a front view of the second type of boron-containing quartz component 95. [Figure 4] Figure 4 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (A). Figure 4(A) is a plan view of the quartz injection head 90. Figure 4(B) is a cross-sectional view taken along the arrow AA. Figure 4(C) is a front view of the quartz injection head 90. Figure 4(D) is a perspective view of the quartz injection head 90. [Figure 5] Figure 5 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (B). Figure 5(A) shows a plan view of the quartz injection head 90. Figure 5(B) is missing. Figure 5(C) shows a cross-sectional view taken along the BB arrow. Figure 5(D) shows a perspective view of the quartz injection head 90. [Figure 6] Figure 6 shows the regularly arranged numerous holes of the quartz injection head 90 that satisfy equation (C). Figure 6(A) shows a plan view of the quartz injection head 90. Figure 6(B) is missing. Figure 6(C) shows a cross-sectional view taken along arrow BB. Figure 4(D) shows a perspective view of the quartz injection head 90. [Figure 7]Figure 7 is a reference diagram for the calculation method of airflow (plasma flow) (Part 1). [Figure 8] Figure 8 is a reference diagram in the calculation method for airflow (plasma flow) (Part 2). Figure (A) shows a perspective view in the calculation method for airflow (plasma flow) (Part 2). Figure (B) shows a cross-sectional view when a fluid flows into a hole in the boron-containing quartz component 95 at an incidence angle θ (°). Figure (C) shows the view from arrow AA in Figure (B), where the cross-sectional area of ​​the airflow = the cross-sectional area of ​​the hole = (π / 4)d² (cm). [Figure 9] Figure 9 shows the relationship between the XYZ coordinate system and the six-view drawings (front view, rear view, top view, bottom view, left side view, and right side view). [Figure 10] Figure 10(A) is a perspective view of the quartz injection head 90. Figure 10(B) is a front cross-sectional view of the boron-containing quartz component 95. The upper part of Figure (B) shows a front cross-sectional view of the boron-containing quartz component 95 that satisfies equation (A). The middle part of Figure (B) shows a front cross-sectional view of the boron-containing quartz component 95 that satisfies equation (B). The lower part of Figure (B) shows a front cross-sectional view of the boron-containing quartz component 95 that satisfies equation (C). [Figure 11] Figure 11(A) is a front view of the invention, showing the area of ​​chamber CB (the area with thick diagonal lines). Figure 11(B) is an enlarged view of the front view of the invention, showing the area around the gap 10 and the quartz injection head 90. [Explanation of Symbols]

[0010] BD... Boron-containing diamond 100...Boron-containing diamond film deposition manufacturing equipment G0...Film-forming gas S0...Film-forming gas inlet G1... Boron-containing gas S1... Boron-containing gas intake port G2... Exhaust gas E... Exhaust port CB... Chamber CB1... Cylinder-type chamber CB2... Dish-shaped chamber P0... Circuit board P01……Filming table 90... Quartz jet head 95... Boron-containing quartz component 10... Gap

Claims

1. A method for manufacturing a boron-containing diamond film using the MPCVD method, in which a film-forming gas G0 is supplied from a film-forming gas intake port S0 and exhaust gas G2 is discharged from an exhaust port E to form a boron-containing diamond BD on a substrate P0, characterized in that the film-forming gas G0 is supplied from the film-forming gas intake port S0 and a boron-containing quartz component 95 constituting a quartz injection head 90 is used as a boron-doping element source.

2. The method for producing a boron-containing diamond film according to claim 1, characterized in that the film-forming gas G0 consists of a mixed gas of methane gas and hydrogen gas.

3. A method for producing a boron-containing diamond film according to claim 1, characterized in that a quartz injection head 90 made of boron-containing quartz components 95 is installed on a film deposition stage P01 located in the center of a chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm.

4. A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the diameter d (cm) and diameter position r (cm) of the quartz injection head 90 satisfy formula (A). A method for producing a boron-containing diamond film according to claim 1, characterized by the above. d=C1 / r...Formula (A) Here, the diameter position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. C1 is a constant (cm ２ ) refers to.

5. A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the diameter d (cm) and the position r (cm) of the hole of the quartz injection head 90 satisfy formula (B). d=const. ...Formula (B) Here, the diameter position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. "Const." refers to a constant (cm).

6. A method for producing a boron-containing diamond film according to any one of claims 1 to 3, characterized in that the diameter d (cm) and the position r (cm) of the hole of the quartz injection head 90 satisfy formula (C). d=C2 / cos(θ)...Formula (C) Here, the diameter position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). C² refers to the constant (cm).

7. A boron-containing diamond film deposition manufacturing apparatus 100 that utilizes an MPCVD apparatus 99 for depositing boron-containing diamond on a substrate P0, comprising a film deposition gas intake port S0 for supplying film deposition gas G0, an exhaust port E for discharging exhaust gas G2, and a boron-containing quartz component 95 that constitutes a quartz injection head 90 as a boron-doping element source.

8. The boron-containing diamond film deposition apparatus 100 according to claim 7, characterized in that the film deposition gas G0 consists of a mixed gas of methane gas and hydrogen gas.

9. A boron-containing diamond film deposition apparatus 100 according to claim 7, characterized in that a quartz injection head 90 made of boron-containing quartz components 95 is installed on a film deposition stage P01P01 located in the center of the chamber CB, the upper part of the injection head 90 is adjacent to the upper part of the chamber CB, and the gap 10 is less than 1 mm.

10. A boron-containing diamond film manufacturing apparatus 100 according to any one of 7 to 9, characterized in that the diameter d (cm) and the position r (cm) of the hole of the quartz injection head 90 satisfy formula (A). d=C1 / r...Formula (A) Here, the diameter position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. C1 is a constant (cm ２ ) refers to.

11. A boron-containing diamond film manufacturing apparatus 100 according to any one of 7 to 9, characterized in that the diameter d (cm) and the position r (cm) of the hole of the quartz injection head 90 satisfy formula (B). d=const. ...Formula (B) Here, the diameter position r refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. "Const." refers to a constant (cm).

12. A boron-containing diamond film manufacturing apparatus 100 according to any one of claims 7 to 9, characterized in that the diameter d (cm) and the position r (cm) of the hole of the quartz injection head 90 satisfy formula (C). d=C2 / cos(θ)...Formula (C) Here, the diameter position r (cm) refers to the distance (cm) from the center O of the quartz injection head 90 to the center of the hole with a diameter d (cm) of the quartz injection head 90. θ represents the angle of incidence (°). "Const." refers to a constant (cm).

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