Source: http://www.google.com/patents/US6096129?dq=6016038
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Patent US6096129 - Method of and apparatus for producing single-crystalline diamond of large size - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn initial single-crystalline diamond base material is prepared from a flat plate having a major surface and side surfaces consisting of low-index planes. Then, single crystalline diamond is homoepitaxially vapor-deposited on the single-crystalline diamond base material, and a resulting diamond material...http://www.google.com/patents/US6096129?utm_source=gb-gplus-sharePatent US6096129 - Method of and apparatus for producing single-crystalline diamond of large sizeAdvanced Patent SearchPublication numberUS6096129 APublication typeGrantApplication numberUS 09/060,555Publication dateAug 1, 2000Filing dateApr 15, 1998Priority dateApr 18, 1997Fee statusPaidAlso published asDE69802037D1, DE69802037T2, EP0879904A1, EP0879904B1Publication number060555, 09060555, US 6096129 A, US 6096129A, US-A-6096129, US6096129 A, US6096129AInventorsHirohisa Saito, Takashi Tsuno, Takahiro Imai, Yoshiaki KumazawaOriginal AssigneeSumitomo Electric Industries, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (7), Non-Patent Citations (14), Referenced by (24), Classifications (19), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetMethod of and apparatus for producing single-crystalline diamond of large size
US 6096129 AAbstract
An initial single-crystalline diamond base material is prepared from a flat plate having a major surface and side surfaces consisting of low-index planes. Then, single crystalline diamond is homoepitaxially vapor-deposited on the single-crystalline diamond base material, and a resulting diamond material is cut and polished in a particular manner to provide a successive base material on which single-crystalline diamond is again grown, thereby forming a single-crystalline diamond having a large area. A holder for the single-crystalline diamond base material consists of or is coated with a material hardly forming a compound with carbon. Single crystalline diamond can be stably formed on the surfaces of the base material. Consequently, single-crystalline diamond of high quality having a large area can be stably produced in a shorter time using either plasma CVD or a thermal filament method.
1. A method of producing single-crystalline diamond comprising the following steps:a) providing a single-crystalline diamond base material having a base material major surface and base material side surfaces respectively extending along low-index planes; b) vapor-depositing single-crystalline diamond on said base material major surface and said base material side surfaces to form an intermediate product; and c) cutting said intermediate product along at least one cutting plane substantially perpendicular to said base material major surface so as to cut out a cut single-crystalline diamond product from said intermediate product, wherein said single-crystalline diamond product has cut product side surfaces that extend along different low-index planes in comparison to said low-index planes along which said base material side surfaces extend. 2. The method according to claim 1, wherein said low-index planes are selected from {100}, {110}, and {111} planes, planes within 5� with respect to {100}, {110} or {111} planes, {311}, {331}, {511}, {551}, and {771} planes, and planes within 1� with respect to {311}, {331}, {511}, {551} or {771} planes.
3. The method according to claim 1, wherein said step of vapor-depositing single-crystalline diamond is performed under a <100> orientation condition, using a methane concentration of at least 8% and a substrate temperature of not more than 1000� C.
4. The method according to claim 1, wherein said step of vapor-depositing single-crystalline diamond is carried out under a <100> orientation condition with a growth rate ratio defined as V<100>/V<111> being at least 30.5, wherein V<100> is a vapor deposition rate in a <100> direction and V<111> is a vapor deposition rate in a <111> direction.
5. The method according to claim 1, wherein said step of vapor-depositing single-crystalline diamond is carried out under a <110> orientation condition with a growth rate ratio defined as V<100>/V<111> being at least 0.5�30.5 wherein V<100> is a vapor deposition rate in a <100> direction and V<111> is a vapor deposition rate in a <111> direction.
6. The method according to claim 1, wherein said step of vapor-depositing single-crystalline diamond is carried out under a <111> orientation condition with a methane concentration of not more than 1.5%, a substrate temperature of 1100� C., and a growth rate ratio defined as V<100>/V<111> being not more than 3-0.5 wherein V<100> is a vapor deposition rate in a <100> direction and V<111> is a vapor deposition rate in a <111> direction.
7. The method according to claim 1, wherein said low-index plane along which said base material major surface extends is a plane oriented within 5� of {100} planes, said low-index planes along which said base material side surfaces extend respectively are planes oriented within 5� of {111} planes, and said base material has a total of four of said base material side surfaces.
9. The method according to claim 8, wherein said low index planes along which said base material side surfaces extend are respective planes having an inclination of not more than 5� relative to {100} planes, and wherein said different low-index planes along which said cut product side surfaces extend are respective planes having an inclination of not more than 5� relative to {110} planes.
10. The method according to claim 9, further comprising providing said cut single-crystalline diamond product as a successive base material, vapor-depositing single-crystalline diamond on a major surface of said successive base material to form an enlarged intermediate product, and cutting said enlarged intermediate product to cut out from said enlarged intermediate product an enlarged cut single-crystalline diamond product having enlarged cut product side surfaces extending along respective planes having an inclination of not more than 5� relative to {100} planes.
11. The method according to claim 8, wherein said low index planes along which said base material side surfaces extend are respective planes having an inclination of not more than 5� relative to {110} planes, and wherein said different low-index planes along which said cut product side surfaces extend are respective planes having an inclination of not more than 5� relative to {100} planes.
12. The method according to claim 11, further comprising providing said cut single-crystalline diamond product as a successive base material, vapor-depositing single-crystalline diamond on a major surface of said successive base material to form an enlarged intermediate product, and cutting said enlarged intermediate product to cut out from said enlarged intermediate product an enlarged cut single-crystalline diamond product having enlarged cut product side surfaces extending along respective planes having an inclination of not more than 5� relative to {110} planes.
13. The method according to claim 1, wherein said steps of vapor-depositing and cutting are successively repeated while successively using said cut product of said step c) as said base material for a successive repetition of said step b), so as to produce a single-crystalline diamond of a size of about 10 mm�10 mm.
19. The method according to claim 16, wherein said step of vapor-depositing single-crystalline diamond is performed under a <100> orientation condition using a methane concentration of at least 8% and a substrate temperature of not more than 1000� C.
20. The method according to claim 16, wherein said step of vapor-depositing single-crystalline diamond is performed under a <100> orientation condition, with a growth rate ratio defined as V<100>/V<111> being at least 30.5, wherein V<100> is a vapor deposition rate in a <100> direction and V<111> is a vapor deposition rate in a <111> direction.
21. The method according to claim 16, wherein said low-index planes are-selected from {100}, {110}, and {111} planes, planes within 5� with respect to {100}, {110} or {111} planes, {311}, {331}, {511}, {551}, and {771} planes, and planes within 1� with respect to {311}, {331}, {511}, {551} or {771} planes.
23. A method of producing single-crystalline diamond comprising the following steps:a) providing a single-crystalline diamond base material having two major surfaces extending along low-index planes and four side surfaces extending along planes respectively having an inclination within 5� with respect to {110} planes; b) growing single-crystalline diamond on an upper one of said major surfaces and on said side surfaces of said base material so as to form a newly grown upper surface of said single-crystalline diamond grown on said upper major surface of said base material and respective pairs of newly grown inclined surfaces of said single-crystalline diamond grown respectively on said four side surfaces, wherein each of said inclined surfaces respectively has an inclination within 5� with respect to {111} planes and an edge line along an outer edge of said inclined surface protruding outwardly away from said side surface respectively, and terminating said growing no later than a stage at which said edge lines of said inclined surfaces of each said pair respectively join one another at an intersection of said inclined surfaces of each said pair respectively thereby covering any growth plane parallel to a respective one of said side surfaces, so as to form an intermediate product; c) after terminating said growing, removing a first portion of said intermediate product between said newly grown upper surface and a first plane defined by said edge lines of said newly grown inclined surfaces extending from said newly grown upper surface, so as to form a growth-start surface along said first plane, consisting of a plane having an inclination within 5� with respect to a {100} plane; d) vapor-depositing single-crystalline diamond on said growth-start surface to form a new single-crystalline diamond layer; e) removing a second portion of said intermediate product between a lower surface of said intermediate product and said growth-start surface; and f) after said step e), cutting at least said new single-crystalline diamond layer along a plane substantially perpendicular to said growth-start surface so as to cut out a single-crystalline diamond product substantially in a form of a rectangular parallelepiped. 24. The method according to claim 23, wherein said step of vapor-depositing single-crystalline diamond is performed under a <110> orientation condition, with a growth rate ratio defined as V<100>/V<111> being 0.5�30.5, wherein V<100> is the vapor deposition rate in a <100> direction and V<111> is the vapor deposition rate in a <111> direction.
25. The method according to claim 23, wherein said step of vapor-depositing single-crystalline diamond is performed under a <111> orientation condition with a methane concentration of not more than 1.5%, a substrate temperature of 1100� C., and a growth rate ratio defined as V<100>/V<111> being not more than 3-0.5, therein V<100> is the vapor deposition rate in a <100> direction and V<111> is the vapor deposition rate in a <111>direction.
26. The method according to claim 23, wherein said low-index planes are selected from {100}, {110}, and {111} planes, planes within 5� with respect to {100}, {110}, or {111} planes, {311}, {331}, {511}, {551}, and {771} planes, and planes within 10 with respect to {311}, {331}, {511}, {551} or {771} planes.
An object of the present invention is to provide a method of stably producing single-crystalline diamond having a large area, using either plasma CVD or a thermal filament method, and an apparatus for producing the same.
The term "low-index planes" is defined as indicating all of {100}, {110} and {111} planes and those forming angles within 5� with respect to these planes, as well as {311}, {331}, {511}, {551} and {711} planes and those forming angles within 1� with respect to these planes, in Miller indices.
In the single-crystalline diamond base material, the major surface preferably consists of a square plane having an inclination within 5� with respect to {100} planes, and the four side surfaces are preferably prepared from planes having an inclination within 5� with respect to {100} or {110} planes.
The ratio of a vapor deposition rate V<100> in a <100> direction to a vapor deposition rate V<111> in a <111> direction, i.e. a growth rate ratio defined as V<100>/V<111>, is employed as an index of the vapor deposition rate of the single-crystalline diamond on the side surfaces of the base material consisting of such low-index planes. A condition for homoepitaxial growth is determined in response to the plane orientation of the side surfaces of the base material. In more concrete terms, the single-crystalline diamond is grown under a <100> orientation growth condition at a growth rate ratio of at least 1.62, particularly preferably at least 30.5, when the side surfaces of the base material are formed by {100} planes. On the other hand, the single-crystalline diamond is grown under a <110> orientation condition at a growth rate ratio of 0.81 to 0.92, particularly preferably 0.5�30.5, when the side surfaces are formed by {110} planes, or under a <111> orientation growth condition at a growth rate ratio of not more than 0.64, particularly preferably not more than 3-0.5, when the side surfaces are formed by {111} planes. When the side surfaces are formed by two plane orientations, the single-crystalline diamond is grown under a condition responsive to either plane orientation. Thus, the growth rate toward this orientation is at the maximum on extensions of the side surfaces and thereby hardly causes abnormal growth, whereby regions including abnormal growth can be limited.
In another preferred embodiment of the present invention, the single-crystalline diamond base material is prepared from material having a major surface consisting of a square plane having an inclination within 5� with respect to {100} planes and four side surfaces consisting of planes having an inclination within 5� with respect to {100} planes, using a vapor deposition condition that will provide the greatest increase in the vapor deposition rate of the single-crystalline diamond with respect to {111} planes.
When such a <111> orientation condition is employed in place of the <110> orientation condition, the thickness of the {110} side surfaces is not gradually reduced as growth progresses, dissimilarly to the case of the <110> orientation condition, whereby single-crystalline diamond base having a larger area can be readily formed.
In still another preferred embodiment of the present invention, the single-crystalline diamond base material is prepared from material having four side surfaces consisting of planes having an inclination within 5� with respect to {100} planes. Prior to the step of cutting the base material along a plane substantially perpendicular to the major surface of the base material for cutting out single-crystalline diamond that is substantially in the form of a rectangular parallelepiped he inventive method further comprises a step of removing (by grinding or polishing) portions of material between an upper surface and the upper major surface of the single-crystalline diamond base material and between a lower surface and upper ends of inclined surfaces growing from lower sides of the four side surfaces when the upper ends of the inclined surfaces reach the vertical position of the upper major surface of the single-crystalline diamond base material or a preceding stage.
In a further preferred embodiment of the present invention, the single-crystalline diamond base material is prepared from material having four side surfaces consisting of planes having an inclination within 5� with respect to {110} planes. Prior to the step of cutting the base material along a plane substantially perpendicular to the major surface of the base material for cutting out single-crystalline diamond that is substantially in the form of a rectangular parallelepiped, the method further comprises the following steps. A first step involves removing a portion of material between an upper surface formed by growth of the upper major surface of the base material and a plane that includes edge lines formed by intersection lines between pairs of inclined surfaces, have an angle within 5� with respect to {110} planes, and that were vertically oppositely grown on the four side surfaces respectively, in order to form a new growth-start major surface consisting of a plane having an inclination within 5� with respect to a {111} plane when the pairs of inclined surfaces grow until the intersection lines therebetween form the edge lines and cover up the growth planes that are parallel to the four side surfaces or in a preceding stage. A next step involves vapor-depositing the single-crystalline diamond on the new growth start major surface. Thereafter, a further step involves removing a portion of material between the lower surface and the new growth start major surface.
The step of cutting out the single-crystalline diamond substantially in the form of a rectangular parallelepiped by cutting the base material along the planes substantially perpendicular to the major surface includes a step of cutting out the diamond so that planes having an inclination within 5� with respect to {100} planes form new side surfaces when planes having an inclination within 5� with respect to {100} planes form the side surfaces before cutting, or a step of cutting out the diamond so that planes having an inclination within 5� with respect to {100} planes form new side surfaces when planes having an inclination within 5� with respect to {110} planes form the side surfaces before cutting.
According to the inventive method of producing single-crystalline diamond, single-crystalline diamond having a large area is formed by alternately repeating steps of vapor depositing single-crystalline diamond onto single-crystalline diamond base material and then cutting the single-crystalline diamond into a rectangular parallelepiped shape. According to the invention, the steps of cutting include alternately repeating a step of cutting out single-crystalline diamond having side surfaces consisting of planes having an inclination within 5� with respect to {100} planes before cutting so that planes having an inclination within 5� with respect to {110} planes form new side surfaces, and a step of cutting out single-crystalline diamond having side surfaces consisting of planes having an inclination within 5� with respect to {110} planes before cutting so that planes having an inclination within 5� with respect to {100} planes form new side surfaces.
FIG. 1A is a perspective view showing an initial single-crystalline diamond base material having an upper surface of a square {100} plane and side surfaces of {100} planes, which will be employed in each pertinent Example of the present invention.
FIG. 9A is a plan view in case of, illustrating cutting the base material along cut lines 12 forming a square when the growth thickness toward a {100} plane in a <100> direction is preferably about 22% of the initial length of each side of the base material in order to cut out diamond in the form of a square pole.
FIG. 9B is a plan view illustrating cutting the base material along cut lines 12 forming a square on corner portions when the growth thickness toward a {100} plane in a <100> direction is preferably about 22% of the initial length of each side of the base material similarly to the case shown in FIG. 9A, in order to cut out diamond in the form of an octagonal pole.
FIG. 9C is a plan view illustrating cutting the base material along cut lines 12 forming a square when the vapor deposition thickness toward a {100} plane in a <100> direction is preferably about 50% of the initial length of each side of the base material, in order to cut out diamond in the form of a square pole.
FIG. 10 is a model diagram showing a microwave CVD apparatus for diamond vapor-phase synthesis employed for an experiment in Example 1 of the present invention. In the microwave CVD apparatus shown in FIG. 10, a microwave generator comprising a microwave power source 4, an isolator, tuners 5 and the like generates microwaves, which are directed to a plunger 10 through a waveguide 6. The waveguide 6 is provided in an intermediate position thereof with a silica tube 7 that serves as a reaction vessel. The silica tube 7 is provided with a source gas inlet port 9 and an outlet port 8 on its upper and lower portions respectively. A base material holder 1 is arranged at a position of the silica tube 7 that intersects with the waveguide 6, so that a base material 2 can be set on this base material holder 1.
A base material (hereinafter referred to as a prime base material) 50 shown in FIGS. 1A and 4A is prepared from single-crystalline diamond of at least 0.5 mm in thickness having an upper surface 50a of a square {100} plane and side surfaces 50b and 50c of {100} planes and is set on the base material holder 1, which is made of molybdenum, in the microwave CVD apparatus shown in FIG. 10. Then, diamond is homoepitaxially grown under a <100> preferential orientation growth condition at a growth rate ratio of about 30.5 with methane-hydrogen mixed gas having a methane concentration of 10�0.5% while maintaining the pressure in the reaction vessel 7 at 140�5 Torr and the temperature of the prime base material 50 at 1000�10� C. Under these conditions diamond grows as shown in FIGS. 1B, 3A and 4B so that inclined surfaces 51 appear from lower portions of the side surfaces 50b and 50c of the prime base material 50 while abnormal growing parts 11 (see FIG. 4B) and depressed parts 52 appear on the four corners and upper corner portions of an upper surface respectively.
Then, diamond is grown under a <110> preferential orientation growth condition at a growth rate ratio of 0.5 �30.5 with methane-hydrogen mixed gas having methane concentration of 3+0.5% while maintaining the pressure in the reaction vessel 7 at 140�5 Torr and the temperature of the prime base material 60 at 1050�10� C., whereby the diamond grows as shown in FIGS. 5B and 7A. Due to the aforementioned step, inclined surfaces 61 and 62 appear as shown in FIGS. 5B and 8B from upper and lower ends of the four side surfaces 60b and 60c of the prime base material 60 shown in FIGS. 5A and 8A. While abnormal growing parts 11 appear on the four corners of the prime base material 60, the diamond grows with no abnormal growth on the extensions of the {110} side surfaces 60b and 60c.
The diamond grows until intersection lines 63a between the inclined surfaces 61 and 62 appearing from the upper and lower ends of the side surfaces 60b and 60c form edge lines 63 as shown in FIG. 5C. A portion between an upper surface 63b and a plane that includes the edge lines 63 is removed by polishing so that a surface having no abnormal growth appears as a front surface, thereby forming a substrate 64 having a growth start surface 64a shown in FIG. 6A. Then, the <100> preferential orientation growth condition is applied to homoepitaxially grow diamond on the growth-start surface 64a, thereby forming a single-crystalline diamond layer 65 on the substrate 64, as shown in FIG. 6B. Thereafter the substrate 64 located under the single-crystalline diamond layer 65 is removed by polishing from a lower surface 64b, to obtain the flat single-crystalline diamond layer 65 including the abnormal growing parts 11 on the four corners as shown in FIGS. 6C and 8C. This single-crystalline diamond layer 65 is cut with a YAG laser beam along cut lines 12 shown in FIG. 6C, thereby forming single-crystalline diamond 50 having an upper surface 50a and four side surfaces 50b and 50c all consisting of {100} planes and having no abnormal growing parts, as shown in FIG. 1A. Flat single-crystalline diamond having a large area can be obtained by repeating the aforementioned steps.
While the <110> preferential orientation growth condition is employed in the homoepitaxy step shown in FIG. 5A with the single-crystalline substrate 60 serving as a prime base material in this Example, the object of the present invention can also be attained by employing a <111> preferential orientation growth condition to obtain the greatest increase in the growth rate in <111> directions, instead of the <110> preferential orientation growth condition, for the following reason.
It is generally known that isolated grains of diamond that are formed by homoepitaxy from points are generally formed by two types of planes, i.e. {100} and {111} planes. This is because the diamond mainly grows toward the {100} and {111} planes in <100> and <111> directions while relatively hardly growing toward the remaining planes. As understood from the fact that the growth rate ratio as an index specifying each orientation growth direction, is defined as the ratio of the vapor deposition rate V<100> in the <100> direction to the vapor deposition rate V<111> in the <111> direction, it is therefore also known that the growth rates toward the remaining low-index planes are determined by the large-small relation between the growth rates in the <100> and <111> directions.
When the <110> preferential orientation growth condition is applied to the prime base material 60 shown in FIG. 5A as described above, the growth rate ratio is 0.5�30.5 and the vapor deposition rate in the <111> direction is higher than that in the <100> direction, whereby the growth of the diamond is remarkably influenced by the vapor deposition in the <111> direction. Therefore, the diamond grows into the shape shown in FIG. 7A after vapor deposition, and the thickness of each {110} plane is gradually reduced as shown in FIG. 7B, thereby reducing the thickness of each region, that causes no abnormal growth. When the <111> preferential orientation growth condition is applied to the prime base material 60 shown in FIG. 5A in place of the <110> preferential orientation condition, on the other hand, it is possible to grow the diamond without reducing the thickness of the regions that do not cause abnormal growth. Namely, the object of the present invention can also be attained by applying the <111> orientation growth condition dissimilarly to the <110> orientation growth condition to achieve the greatest increase in the growth rate toward the side surfaces, when homoepitaxially growing diamond on a prime base material having a major surface of a {100} plane and side surfaces of {110} planes.
FIGS. 9A to 9C illustrate preferable ranges of growth thicknesses of single-crystalline diamond toward side surfaces of base materials for the stages of cutting the base materials. First, consider the case of cutting the base material into the form of a square pole having no abnormal growing parts 11 when the growth thickness toward each {100} plane in a <100> direction is about 22% of the initial length of each side of the base material. Cut lines 12, shown in FIG. 9A, form respective sides of a square, i.e. along {110} planes in four corners. In this case, the area s1 of a triangle formed on each corner of diamond, that is cut out from the initial base material and remains as a new corner of the diamond after it is cut is substantially identical to the area s2 of each previously grown part that is cut off. Consequently, the plane area of the cut base material is substantially equal to that of the base material. If the base material is cut along the {110} planes across the four corners to form a square pole while removing the abnormal growing parts when the growth thickness toward the {100} planes in the <100> directions is not in excess of about 22% of the initial length of each side of the base material, the plane area of the cut base material is then merely identical to or smaller than that of the initial base material. When cutting out diamond in the form of a flat square, therefore, it is necessary to cut the base material when the growth thickness toward the {100} planes in the <100> directions is at least in excess of about 22% of the initial length of each side of the base material.
Even if the growth thickness toward the {100} planes in the <100> directions is not in excess of about 22% of the initial length of each side of the base material, however, it is possible to obtain a single-crystalline diamond base material having a larger plane area than the initial one by cutting the base material along the lines 12, i.e. along {110} planes on the corner portions so as to cut out diamond in the form of an octagonal pole that includes {100} and {110} planes on its side surfaces, while removing abnormal growing parts 11, as shown in FIG. 9B.
When the growth thickness toward {100} planes in <100> directions is about 50% of the initial length of each side of the base material, cutting the base material along cut lines 12 forming a square, i.e. cutting along {110} planes on four corners to form a square pole while removing abnormal growing parts 11, will result in a new base material having a plane area of about twice the initial one, as can be seen in FIG. 9C. This provides the greatest improvement in efficiency when considering the yield of single-crystalline diamond from which the abnormal growing parts 11 are removed. When the base material is cut after the diamond grows to a growth thickness in excess of 50%, however, single-crystalline diamond portions are excessively removed when removing the abnormal growing parts 11 and the obtained plane area is merely identical to that in the case of 50%. Therefore, the diamond is preferably cut out by cutting the base material along the {110} planes on the four corners when the growth thickness toward the {100} planes in the <100> directions is not more than 50% of the initial length of each side of the base material, and it is most optimum to cut out the diamond when the growth thickness is 50%.
Example 2 of the present invention for vapor-phase synthesizing single-crystalline diamond using a thermal filament method is now described.
The single-crystalline diamond base material 26 is prepared from the single-crystalline diamond base material (prime base material) 50 of at least 0.5 mm in thickness having the upper surface 50a of a square {100} plane and the side surfaces 50b and 50c of {100} planes as shown in FIGS. 1A and 4A. The base material 26 is set on the base material holder 27 of molybdenum provided in the aforementioned thermal filament CVD apparatus. Diamond is homoepitaxially grown under a <100> preferential orientation growth condition at a growth rate ratio of about 30.5 using methane-hydrogen mixed gas having a methane concentration of 1.3% while maintaining the pressure in the reaction vessel 21 at 100 Torr and the temperature of the prime base material 50 at 850� C. Under these conditions, diamond grows as shown in FIGS. 1B, 3A and 4B so that inclined surfaces 51 appear from lower portions or edges of the side surfaces 50b and 50c of the prime base material 50 while abnormal growing parts 11 (see FIG. 4B) and depressed parts 52 appear on four corners and upper corner portions of an upper surface respectively.
Then, diamond is grown under a <110> preferential orientation growth condition at a growth rate ratio of 0.5�30.5 with methane-hydrogen mixed gas having methane concentration of 1.2% while maintaining the pressure in the reaction vessel 27 at 100 Torr and the temperature of the prime base material 60 at 850� C. Under these conditions, diamond grows as shown in FIGS. SB and 7A. Due to the aforementioned step, inclined surfaces 61 and 62 appear as shown in FIGS. 5B and 8B from upper and lower ends of the four side surfaces 60b and 60c of the prime base material 60 shown in FIGS. 5A and 8A. While abnormal growing parts 11 appear on four corners of the prime base material 60, the diamond grows with no abnormal growth on extensions of the {110} side surfaces 60b and 60c.
The diamond grows until intersection lines 63a between the inclined surfaces 61 and 62 appearing from the upper and lower ends of the side surfaces 60b and 60c form edge lines 63 as shown in FIG. 5C. Then, a portion between an upper surface 63b and a plane including the edge lines 63 is removed by polishing so that a surface having no abnormal growth appears as a front surface, thereby forming a substrate 64 having a growth-start surface 64a shown in FIG. 6A. Then, the <100> preferential orientation growth condition is applied to homoepitaxially grow diamond on the growth-start surface 64a, thereby forming a single-crystalline diamond layer 65 on the substrate 64, as shown in FIG. 6B. Thereafter the substrate 64 located under the single-crystalline diamond layer 65 is removed by polishing from a lower surface, to obtain the flat single-crystalline diamond layer 65 that includes the abnormal growing parts 11 on four corners as shown in FIGS. 6C and 8C. This single-crystalline diamond layer 65 is cut with a YAG laser beam along cut lines 12 shown in FIG. 6C, thereby forming single-crystalline diamond having an upper surface 50a and four side surfaces 50b and 50c, all consisting of {100} planes and having no abnormal growing parts as shown in FIG. 1A. Flat single-crystalline diamond having a large area can be obtained by repeating the aforementioned steps.
Also in this Example, the object of the present invention can be attained by applying the <111> preferential orientation growth condition dissimilarly to the <110> preferential orientation growth condition to obtain the greatest increase in the growth rate toward the side surfaces when homoepitaxially growing diamond on a prime base material having a major surface of a {100} plane and side surfaces of {110} planes similarly to Example 1, as a matter of course.
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Res., vol. 10, No. 12, Dec. 1995, pp. 3115 to 3123.11 *Hiromu Shiomi et al.: Epitaxial Growth of High Quality Diamond Film by the Microwave Plasma Assisted Chemical Vapor Deposition Method; 362 Japanese Journal of Applied Physics, 29(1990)Jan., No. 1, Part 1, Tokyo, JP, pp. 34 to 40.12Hiromu Shiomi et al.: Epitaxial Growth of High Quality Diamond Film by the Microwave Plasma-Assisted Chemical-Vapor-Deposition Method; 362 Japanese Journal of Applied Physics, 29(1990)Jan., No. 1, Part 1, Tokyo, JP, pp. 34 to 40.13 *Morphology and Quantitiative Nitrogen Impurity Measurements in Homoepitaxial Chemical Vapor Deposited Diamond ; by Catledge et al.; Mat.Res.Soc.Symp.Proc.vol.441, 1997; pp. 635 640.14 *Mosaic growth of diamond; Janssen et al.; Diamond and Related Materials, No. 4 (1995) pp. 1025 1031.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7060130Aug 5, 2003Jun 13, 2006Board Of Trustees Of Michigan State UniversityHeteroepitaxial diamond and diamond nuclei precursorsUS7736435 *Nov 16, 2005Jun 15, 2010National Institute Of Advanced Industrial Science And TechnologyMethod of producing single crystalUS7964280 *Jun 22, 2006Jun 21, 2011Stephen David WilliamsHigh colour diamond layerUS8342164 *Jan 1, 2013SCIO Diamond Technology CorporationGemstone production from CVD diamond plateUS8574535Mar 7, 2008Nov 5, 2013Element Six LimitedDiamondUS9017633Jan 14, 2011Apr 28, 2015Element Six Technologies LimitedCVD single crystal diamond materialUS9034296Sep 6, 2013May 19, 2015Element Six Technologies LimitedDiamondUS9039832Jan 15, 2010May 26, 2015Element Six Technologies LimitedHigh pressure high temperature (HPHT) method for the production of single crystal diamondsUS9157170Dec 15, 2010Oct 13, 2015Element Six Technologies LimitedSingle crystal diamond materialUS9227343 *Dec 31, 2012Jan 5, 2016SCIO Diamond Technology CorporationGemstone production from CVD diamond plateUS20040069209 *Aug 5, 2003Apr 15, 2004Board Of Trustees Of Michigan State UniversityHeteroepitaxial diamond and diamond nuclei precursorsUS20060266279 *Nov 16, 2005Nov 30, 2006National Institute Of Advanced Industrial Science And TechnologyMethod of producing single crystalUS20100015438 *Jun 22, 2006Jan 21, 2010Stephen David WilliamsHigh colour diamond layerUS20100059034 *May 8, 2009Mar 11, 2010Apollo Diamond Gemstone CorporationGemstone production from cvd diamond plateUS20100111812 *Jan 8, 2010May 6, 2010Sumitomo Electric Industries, Ltd.Single crystalline diamond and producing method thereofUS20100119790 *Mar 7, 2008May 13, 2010Carlton Nigel DodgeDiamondUS20110150745 *Dec 15, 2010Jun 23, 2011Daniel James TwitchenSingle crystal diamond materialUS20110176563 *Jul 21, 2011Ian FrielCvd single crystal diamond materialUS20130192579 *Dec 31, 2012Aug 1, 2013SCIO Diamond Technology CorporationGemstone production from cvd diamond plateCN102959138A *Dec 15, 2010Mar 6, 2013六号元素有限公司Single crystal diamond materialCN102959138B *Dec 15, 2010May 6, 2015六号元素有限公司单晶金刚石材料WO2011076642A1Dec 15, 2010Jun 30, 2011Element Six LimitedSingle crystal diamond materialWO2011086164A1Jan 14, 2011Jul 21, 2011Element Six LimitedCvd single crystal diamond materialWO2014028831A1 *Aug 16, 2013Feb 20, 2014Gtat CorporationSystem and method of growing silicon ingots from seeds in a crucible and manufacture of seeds used therein* Cited by examinerClassifications U.S. Classification117/84, 117/902, 117/913, 117/93, 117/89International ClassificationC30B29/04, H01L21/205, C30B25/00, C30B25/10, C30B25/02Cooperative ClassificationC30B29/04, Y10S117/902, Y10S117/913, C30B25/105, C30B25/00, C30B25/02European ClassificationC30B25/00, C30B25/10B, C30B25/02Legal EventsDateCodeEventDescriptionApr 15, 1998ASAssignmentOwner name: SUMITOMO ELECTRIC INDUSTRIES, LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SAITO, HIROHISA;TSUNO, TAKASHI;IMAI, TAKAHIRO;AND OTHERS;REEL/FRAME:009156/0213;SIGNING DATES FROM 19980331 TO 19980401Aug 7, 2001CCCertificate of correctionJan 5, 2004FPAYFee paymentYear of fee payment: 4Jan 4, 2008FPAYFee paymentYear of fee payment: 8Sep 21, 2011FPAYFee paymentYear of fee payment: 12RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services