Abstract: Carbon nanotubes are formed on a surface of a substrate using a plasma chemical deposition process. After the nanotubes have been grown, a purification step is performed on the newly formed nanotube structures. The purification removes graphite and other carbon particles from the walls of the grown nanotubes and controls the thickness of the nanotube layer. The purification is performed with the plasma at the same substrate temperature. For the purification, the hydrogen containing gas added as an additive to the source gas for the plasma chemical deposition is used as the plasma source gas. Because the source gas for the purification plasma is added as an additive to the source gas for the chemical plasma deposition, the grown carbon nanotubes are purified by reacting with the continuous plasma which is sustained in the plasma process chamber. This eliminates the need to purge and evacuate the plasma process chamber as well as to stabilize the pressure with the purification plasma source gas.

Abstract: A method of making a Schottky diode comprising the steps of: providing a single crystal diamond comprising a surface; placing the single crystal diamond in a CVD system; heating the diamond to a temperature of at least about 950° C.; providing a gas mixture capable of growing diamond film and comprising a sulfur compound through the CVD system; growing an epitaxial diamond film on the surface of the single crystal diamond; baking the diamond at a temperature of at least about 650° C. in air for a period of time that minimizes oxidation of the diamond; and fabricating a Schottky diode comprising the diamond film. A Schottky diode comprising an epitaxial diamond film and capable of blocking at least about 6 kV in a distance of no more than about 300 &mgr;m.

Abstract: MEMS structure and a method of fabricating them from ultrananocrystalline diamond films having average grain sizes of less than about 10 nm and feature resolution of less than about one micron . The MEMS structures are made by contacting carbon dimer species with an oxide substrate forming a carbide layer on the surface onto which ultrananocrystalline diamond having average grain sizes of less than about 10 nm is deposited. Thereafter, microfabrication process are used to form a structure of predetermined shape having a feature resolution of less than about one micron.

Abstract: An electrically conducting n-type ultrananocrystalline diamond (UNCD) having no less than 1019 atoms/cm3 of nitrogen is disclosed. A method of making the n-doped UNCD. A method for predictably controlling the conductivity is also disclosed.

Abstract: Novel uses of diamondoid-containing materials in the field of microelectronics are disclosed. Embodiments include, but are not limited to, thermally conductive films in integrated circuit packaging, low-k dielectric layers in integrated circuit multilevel interconnects, thermally conductive adhesive films, thermally conductive films in thermoelectric cooling devices, passivation films for integrated circuit devices (ICs), and field emission cathodes. The diamondoids employed in the present invention may be selected from lower diamondoids, as well as the newly provided higher diamondoids, including substituted and unsubstituted diamondoids. The higher diamondoids include tetramantane, pentamantane, hexamantane, heptamantane, octamantane, nonamantane, decamantane, and undecamantane.

Abstract: Disclosed are compositions comprising one or more undecamantanes. Specifically disclosed are compositions comprising 25 to 100 weight percent of one or more undecamantanes. Also disclosed are novel processes for the separation and isolation of undecamantane components into recoverable fractions from a feedstock containing at least a higher diamondoid component which contains one or more undecamantane components.

Abstract: A mandrel for use in a diamond deposition process has surfaces with different diamond adhesion properties. According to one embodiment, a mandrel is provided and has first and second surfaces on which a diamond film is deposited, with the second surface forming a perimeter around the first surface. The first surface of the mandrel has a first diamond bonding strength which is less than a second diamond bonding strength of the second surface. In an embodiment for forming a cup-shaped diamond film, the mandrel is a titanium nitride (TiN) coated molybdenum (Mo) substrate having a stepped solid cylindrical shape with a central mesa having a side wall or flank. The side wall is etched near the top surface of the mesa to expose a molybdenum band and to form a second surface which bounds the TiN first surface.

Abstract: A film (carbon and/or diamond) for a field emitter device, which may be utilized within a computer display, is produced by a process utilizing treatment of a substrate and then depositing the film. The treatment step creates nucleation and growth sites on the substrate for the film deposition process and promotes election emission of the deposited film. With this process, a patterned emission can be achieved without post-deposition processing of the film. A field emitter device can be manufactured with such a film.

Abstract: A method is described for the production of a suitable substrate for the subsequent growth of a mono-crystalline diamond layer. This method includes the following steps: Selection of a substrate of a mono-crystalline material having a fixed lattice constant (aSi) or with a layer consisting of such a material. Manufacture of a strained silicon layer with foreign material atoms incorporated at substitutional lattice sites on the mono-crystalline material of the substrate. Transfer of the strained layer into an at least partly relaxed state in which it adopts by relaxation and through the selected foreign material concentration a lattice constant (aSi(C) which satisfies the condition n.aSi(C)=m.aD, wherein n and m are integers and aD is the lattice constant of diamond, with the relaxed layer forming the substrate or substrate surface for the epitaxial growth.

Abstract: Synthetic monocrystalline diamond compositions having one or more monocrystalline diamond layers formed by chemical vapor deposition, the layers including one or more layers having an increased concentration of one or more impurities (such as boron and/or isotopes of carbon), as compared to other layers or comparable layers without such impurities. Such compositions provide an improved combination of properties, including color, strength, velocity of sound, electrical conductivity, and control of defects. A related method for preparing such a composition is also described, as well as a system for use in performing such a method, and articles incorporating such a composition.

Abstract: An apparatus for producing diamond in a deposition chamber including a heat-sinking holder for holding a diamond and for making thermal contact with a side surface of the diamond adjacent to an edge of a growth surface of the diamond, a noncontact temperature measurement device positioned to measure temperature of the diamond across the growth surface of the diamond and a main process controller for receiving a temperature measurement from the noncontact temperature measurement device and controlling temperature of the growth surface such that all temperature gradients across the growth surface are less than 20° C.

Abstract: A low free energy method for more rapidly diffusing an impurity as exemplified by boron, into a natural or synthetic diamond or other crystalline element in powdered or granular form, without degradation of the crystalline structure. The present method includes the steps of providing a mixture of the diamond or other crystalline element and the impurity in a solid phase; treating the mixture to bring the impurity into conforming contact with the outer surface of the crystalline element; and heating the mixture to a temperature between about 200° C. and about 2000° C. As an example, a diamond is disclosed having boron as an impurity diffused into the crystalline structure thereof by the present method, at a ratio of from about 0.1 part of the impurity per 1 million parts of the diamond to about 600 parts of the impurity per 1 million parts of the diamond.

Abstract: A method of forming a diamond film includes synthesizing a diamond film on a surface of a substrate, where the surface of the substrate has trenches. The trenches inhibit delamination of the diamond film.

Abstract: An easy method of forming purified carbon nanotubes from which graphitic phase or carbon particles are removed, using a high-density plasma. Carbon nanotubes are grown on a substrate using a plasma chemical vapor deposition method at a high plasma density of 1011 cm−3 or more. The carbon nanotube formation includes: growing a carbon nanotube layer on a substrate to have a predetermined thickness by plasma deposition; purifying the carbon nanotube layer by plasma etching; and repeating the growth and the purification of the carbon nanotube layer. For the plasma etching, a halogen-containing gas, for example, a carbon tetrafluoride gas, is used as a source gas.

Abstract: A method of synthesizing an even free-standing diamond film without growth cracks is disclosed. The intrinsic tensile stress of a diamond film is compensated by an artificial compressive stress with a step down control of the deposition temperature during deposition. After a diamond film is deposited with a predetermined thickness at a deposition temperature, the deposition temperature is decreased in multiple steps during the deposition. The bending of the diamond wafer is minimized by using a tungsten substrate with higher elastic modulus than molybdenum.

Abstract: The present invention describes a novel abrasive tool that contains abrasive particles distributed in a predetermined pattern. Such a pattern is produced by fabricating two-dimensional slices and subsequently assembling and consolidating them into a three-dimensional tool. Abrasive particles 20 may be incorporated during the process of making these two-dimensional slices, or they may be planted afterwards into these slices 100 that contains matrix powder. In the latter case, the planting may be guided by a template 110 with apertures 114 laid in a specific pattern.

Abstract: A polycrystalline carbon body is converted to a different crystallography by directing an infrared laser beam at a crystal boundary interface. By using a beam having a 5.3 micron wavelength so as to fall within a 5-9 micron range of normal spectral transmittance of the carbon, the interface is heated for solid state conversion by passing the beam through a forward portion of the body without appreciably heating the forward portion. During heating, the interface propagates through the body, thus converting an ever-decreasing aft portion of the body to the different crystallography.

Abstract: A method for making n-type semiconducting diamond by use of CVD in which n-type impurities are doped simultaneously with the deposition of diamond. As the n-type impurities, an Li compound and a B compound, both, are used at once. After doping, a diamond film thus obtained is etched to peel off its surface. The n-type semiconducting diamond is superior in specific resistivity, 10.sup.-2 .OMEGA.cm or less.

Abstract: A method for solid state formation of diamond includes providing a diamond growth substrate, such as single-crystal silicon, forming on the diamond growth substrate an alloy of carbon and a metal which permits carbon to exist in a matrix therein, and causing carbon atoms from the alloy to precipitate on the diamond growth substrate in a diamond cubic lattice. The alloy may be an alloy of aluminum and carbon. The alloy is annealed in a hydrogen ambient to cause diffusion of hydrogen through the alloy to the surface of the substrate, providing a high concentration of hydrogen at the interface between the substrate and the alloy. The alloy is heated to cause carbon atoms in the alloy to diffuse through the alloy to the interface and form diamond.

Abstract: Diamond films and novel method to grow the diamond films can improve the performance of products utilizing diamond films. In the cathodoluminescence taken at room temperature, the integrated intensity ratio of the diamond films, CL.sub.1 /CL.sub.2, is equal or greater than 1/20, where CL.sub.1 is the integrated intensity of the emission band in the wavelength region shorter than 300 nm while CL.sub.2 is the integrated intensity of the emission band in the wavelength region from 300 nm to 800 nm. Such high quality diamond films with intensive coalescence on the surface can be obtained by deposition on the substrates or films, made of at least one member selected from the group consisting of platinum, platinum alloys, iridium, iridium alloys, nickel, nickel alloys, silicon, and metal silicides.

Abstract: A method for the growth of diamond on a substrate combines an ECR (Electron cyclotron resonance) MPCVD (Microwave plasma chemical vapor deposition) method with a MPCVD method in one system. A two-step diamond growing method comprises firstly etching and nucleation performed by the ECR method and then diamond grown by the microwave plasma CVD method. Not only are high quality continuous polycrystalline diamond films on silicon wafer obtained but also heteroepitaxial growth has been achieved in the present invention. Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and Raman spectroscopy have been used to characterize the structure and morphology of the synthesized diamond films.

Abstract: There is provided a diamond crystal in which the (111) oriented plane is of the diamond crystal synthesized on a substrate by a chemical vapor deposition method parallel to a substrate surface, and the area of the (111) oriented plane parallel to the substrate surface is 1/24or less an area of the crystal on the substrate. A source gas is activated on a substrate consisting of a material which is not reactive with carbon. The source gas contains at least carbon and hydrogen in such a manner that the ratio of the number of carbon atoms to the total number of molecules of the source gas is 0.5% or less. Subsequently, a diamond crystal in which the (111) orientation plane is parallel to the substrate surface, and the area of the (111) orientation plane parallel to the substrate surface is precipitated on the substrate. A copper plate is preferably contains used as the substrate.

Abstract: A diamond wafer including a substrate and a (100) oriented polycrystalline diamond film grown on the substrate for making surface acoustic wave devices, semiconductor devices or abrasion-resistant discs. The (100) oriented film is produced by changing a hydrocarbon ratio in a material gas halfway from a higher value to a lower value. The wafer is monotonously distorted with a distortion height H satisfying 2 .mu.m.ltoreq..vertline.H.vertline..ltoreq.150 .mu.m. The film is polished to a roughness of less than Rmax50 nm and Ra20 nm.

Abstract: A method to grow diamond crystal by an utilization of liquid template on which carbon precursor is deposited. The liquid template is to replace the conventional solid template to improve the quality and the size of the diamond crystal through the inherent property of the liquid. Its ideal smoothness, its amorphosity and therefore, an absence of the grain boundary, and its high surface mobility for carbon aggregation to form diamond crystal, thus to grow diamond crystal.

Abstract: An article and method of manufacture of a nanocrystalline diamond film. The nanocrystalline film is prepared by forming a carbonaceous vapor, providing an inert gas containing gas stream and combining the gas stream with the carbonaceous containing vapor. A plasma of the combined vapor and gas stream is formed in a chamber and fragmented carbon species are deposited onto a substrate to form the nanocrystalline diamond film having a root mean square flatness of about 50 nm deviation from flatness in the as deposited state.

Abstract: No wide bulk diamond wafer exists at present. A wide diamond-coated wafer is proposed instead of the bulk diamond wafer. Diamond is heteroepitaxially deposited on a convex-distorted non-diamond single crystal substrate by a vapor phase deposition method. In an early step, a negative bias is applied to the substrate. In the case of a Si substrate, an intermediate layer of .beta.-SiC is first deposited on the Si substrate by supplying a low carbon concentration material gas. Then the carbon concentration is raised for making a diamond film. The convex-distorted wafer is stuck to a holder having a shaft which is capable of inclining to the holder. The wafer is pushed to a turn-table of a polishing machine. The convex diamond wafer can fully be polished by inclining the holder to the shaft. A wide distorted mirror wafer of diamond is produced. Fine wire patterns can be made on the diamond mirror wafer by the photolithography.

Abstract: A synthesis of phosphorus-doped diamond by a microwave plasma method using a volatile hydrocarbon and hydrogen mixed therewith, as a reaction gas, wherein phosphorus is used as a dopant, and hydrogen bonded to the phosphorus is dissociated so that the phosphorus is introduced into diamond as an impurity without being bonded to hydrogen.

Abstract: The present invention provides a process for selectively depositing diamond films, which includes two stages of diamond deposition and the gas source used is a mixture of C.sub.x H.sub.y plus CO.sub.2 or C.sub.x H.sub.y O.sub.z plus CO.sub.2. In the period between the first and second stage, the substrate is immersed in an aqueous solution of HF plus HNO.sub.3. The obtained diamond films exhibit good crystallinity and selectivity and the growth rate is fast.

Abstract: Method and apparatus are disclosed for growing diamond films on a non-diamond substrate, such as a silicon wafer. The substrate surface is subjected to nucleation by means of a microwave-generated plasma while applying an electrical bias to the substrate and while an electrode is positioned adjacent to but spaced from the substrate surface. After the nucleation step, crystalline diamond is deposited on the nucleated surface from a carbon-containing plasma.

Abstract: A head drum is coated with double films, each having different characteristics, by forming a first diamond-like hard carbon film of high degree of hardness and then forming a second diamond-like hard carbon film of a lower degree of hardness thereon. The degree of hardness of the second film is lower than that of the first film. The double coating is performed by means of a synthesizing apparatus which comprises a reactor consisting of a power supply electrode, a workpiece support and and an annular ground electrode spaced from the stacked head drums by a predetermined distance.

Abstract: Secondary recrystallized grains having a plurality of crystal orientations in a polycrystalline compact of molybdenum or tungsten, which contains at least one element selected from the group consisting of calcium and magnesium in amount of 0.007 to 0.090 atom %, are formed by locally heating an end portion(s) of the polycrystalline compact. Some grains, which have a prescribed crystal orientation, selected from these secondary recrystallized grains are subsequently grown in the whole polycrystalline compact by annealing.

Abstract: A surface of a diamond, particularly a diamond window, is treated by depositing a layer of a carbide-forming metal such as titanium, on the surface and thereafter removing the layer. The treatment has the effect of passivating stress surface defects in the diamond such as grain boundaries, twin defects and polishing damage.

Abstract: A colorless, transparent low defect density, synthetic type IIa diamond single crystal, in which the etch pits due to needle-shaped defects are at most 3.times.10.sup.5 pieces/cm.sup.2, and which can be applied to uses needing high crystallinity of diamond, for example, monochromators, semiconductor substrates, spectroscopic crystals in X-ray range, electronic materials, etc., is provided by a process for the production of the colorless, transparent low defect density, synthetic diamond single crystal by growing new diamond crystal on a seed crystal of diamond by the temperature gradient method which comprises using a crystal defect-free diamond single crystal, as a seed crystal of diamond, and optionally subjecting to a heat treatment in a non-oxidizing atmosphere at a low pressure and a temperature of 1100 to 1600.degree. C.

Abstract: Processes are disclosed for performing non-microwave, non-arcjet plasma-assisted chemical vapor deposition of diamond in which substantially no particles impact the growing diamond surface with energies sufficient to prevent the growth of diamond. The energies of the particles are limited by selecting frequency, pressure, magnetic fields, electrical bias, or a combination thereof to the deposition region of the chamber. Diamond materials formed by these processes are also disclosed.

Abstract: Diamond materials are formed by sandwiching a carbon-containing material in a gap between two electrodes. A high-amperage electric current is applied between the two electrode plates so as cause rapid-heating of the carbon-containing material. The current is sufficient to cause heating of the carbon-containing material at a rate of at least approximately 5,000.degree. C./sec, and need only be applied for a fraction of a second to elevate the temperature of the carbon-containing material at least approximately 1000.degree. C. Upon terminating the current, the carbon-containing material is subjected to rapid-quenching (cooling). This may take the form of placing one or more of the electrodes in contact with a heat sink, such as a large steel table. The carbon-containing material may be rapidly-heated and rapidly-quenched (RHRQ) repeatedly (e.g., in cycles), until a diamond material is fabricated from the carbon-containing material.

Abstract: Hydrogenated amorphous carbon mainly composed of sp.sup.3 structure is prepared by adding hydrogen to carbon or decomposing hydrogenated carbon gas, and then rapidly cooling the mixed or decomposed gas on a substrate. The hydrogenated amorphous carbon is irradiated with X rays to excite electrons on the 1s shells of carbon atoms. The carbon atoms are rendered to a state excited with 2.sup.+ ion due to Auger effect caused by the exciation, so as to form atomic vacancies and interlattice atomic couples. The hydrogenated amorphous carbon is then annealed, and carbon atoms are rearranged to rotated triangular pattern. Thus, diamond good of crystallinity useful as a high-temperature semiconductor device, ultraviolet laser diode or protective film can be synthesized at a relatively low temperature and a low pressure. The process is applicable for the growth of a diamond single crystal thin film on a single crystal substrate such as amorphous carbon, silicon, or a Group III-V or II-VI compound semiconductor.

Abstract: Provided is a process for economically producing single crystal diamond film with a large surface area by gas-phase synthesis. The process comprises depositing platinum film or platinum alloy film containing more than 50 atomic % of platinum on a basal substrate with (111) or (001) surface while keeping the substrate temperature at 300.degree. C. or above, annealing the platinum or platinum alloy film at 1000.degree. C. or above, and performing the gas-phase synthesis of diamond using said platinum or platinum alloy film as the substrate.

Abstract: A composite structure for electronic components, having a base substrate with a flat side provided with a depression, and having a cover layer which is disposed on the flat side structured by the depression, and the depression being covered to form a hollow structure. The depression in the base substrate is created prior to the deposition of the cover layer and has a clear width measured parallel to the flat side that is less than one-half of its clear depth measured before the cover layer is applied. The vapor phase deposited cover layer is formed from a material which has a sufficiently high surface tension to promote three-dimensional growth of the vapor phase deposited layer.

Abstract: A structure is disclosed for growing semiconductor surfaces. A substrate such as a single crystal silicon substrate is treated by electrical biasing in the presence of a carbon-containing plasma to cause nucleation of the surface. By direct observation using atomic force microscopy (AFM), a nucleated surface consisting of a thin film of mutually parallel, quadrilateral carbon-containing platelets was seen to develop on the substrate. An optimum nucleated surface was determined to be substantially covered with such platelets whose slope relative to the substrate was less than 5.degree.. Such a surface can serve as a template for growing semiconductor films, particularly of diamond, of well defined structure.

Abstract: The invention relates to a composite structure including a semiconductor layer arranged on a diamond layer and/or a diamond-like layer, for subsequent processing to produce electronic components and/or groups of components and to a process for producing such a composite structure. In order to improve the quality of the subsequent components, the diamond layer is deposited underneath the component source zones from which the components are subsequently produced, and the diamond or diamond-like layer is provided at the margins of the component source zones and/or outside of the component source zones with edges where the thickness of the layer changes abruptly such that the edges have an edge height amounting to at least 1O%, preferably at least 50%, of the layer thickness of the diamond layer.

Abstract: A method is related to grow monocrystalline diamond films by chemical vapor deposition on large area at low cost. The substrate materials are either bulk single crystals of Pt or its alloys, or thin films of those materials deposited on suitable supporting materials. The surfaces of those substrates must be either (111) or (001), or must have domain structures consisting of (111) or (001) crystal surfaces. Those surfaces can be inclined within .+-.10 degree angles from (111) or (001). In order to increase the nucleation density of diamond, the substrate surface can be scratched by buff and/or ultrasonic polishing, or carbon implanted. Monocrystalline diamond films can be grown even though the substrate surfaces have been roughened. Plasma cleaning of substrate surfaces and annealing of Pt or its alloy films are effective in growing high quality monocrystalline diamond films.

Abstract: The present invention concerns a novel multilayer system comprising a diamond layer, and the method of manufacturing this multilayer system.The invention concerns a multilayer system comprising a metallic substrate, an interphase and a diamond layer, the interphase being composed of the product of thermal decomposition of at least one metallocene compound.This multilayer system, capable of being used as an electrode, has improved adhesion between the substrate and the diamond layer.

Abstract: A diamond covered member which has a diamond crystal layer is formed by vapor phase synthesis on a surface of a substrate. The process comprises depositing plate-shaped diamond crystals by CVD at a carbon source concentration ranging from 0.01 to 10% at an atomic ratio of oxygen to carbon (O/C) of 0.5.ltoreq.(O/C).ltoreq.1.2 in a starting gas. The crystals may also be deposited by a burning flame method using an oxygen-acetylene flame at a molar ratio of oxygen to acetylene in a main starting gas in the range of 0.9.ltoreq.(O.sub.2 /C.sub.2 H.sub.2).ltoreq.1.0. The plate-shaped diamond crystals are grown to coalesce into a film to form the diamond crystal layer.

Abstract: A method of forming devices having textured and highly oriented diamond layers includes the steps of forming a plurality of diamond nucleation sites on a substrate and then growing diamond on the sites so merge and form a continuous diamond layer having {100} and {111} facets. The growing step is performed by repeatedly cycling between first growth parameters, which favor growth of the nucleation sites in a direction normal to the {100} facets relative to growth in a direction normal to the {111} facets, and second growth parameters, which favor growth of the {100} facets relative to growth of the {111} facets, in sequence. This is continued until a diamond layer of desired thickness is obtained having large and substantially coplanar {100} facets. The first growth parameters are selected so that the rate of growth of diamond in a direction normal to the exposed {100} facets of the layer is preferably between about one and one quarter (1.25) times and one and three quarter (1.

Abstract: Diamond film is deposited by chemical vapor deposition on the surface of a graphite mandrel which is covered with a protective coating to which the diamond film adheres. After completion of the deposition, the diamond is removed from the mandrel by sawing through the substrate to saw off a layer thereof which includes the deposition surface and the diamond film. The graphite and protective coating may be left in place for some applications or be removed either chemically or by mechanical abrasion to separate the diamond therefrom.

Abstract: A method of making n-type semiconducting diamond is disclosed, which is doped with boron-10 at the time of diamond formation and bombarded with neutrons for in-situ conversion of boron-10 to lithium-7, while filtering the neutrons from high energy components during irradiation.

Abstract: A window material, which has a high thermal conductivity material layer having a thermal conductivity of at least 10 W/cm.multidot.K and which has a cooling medium flow path on or in the high thermal conductivity material layer, has a high heat-dissipating property and a high transmittance.

Abstract: A substrate, which has a high thermal conductivity material layer having a thermal conductivity of at least 10 W/cm.multidot.K and which has a cooling medium flow path on or in the high thermal conductivity material layer, has a high heat-dissipating property.

Abstract: A method for bonding CVD diamond to silicon. The first step of the method involves subsequently depositing a transition layer 48 on a diamond layer 46 of a composite wafer 40. Once the transition layer 48 has been deposited, wafer layer 50 comprised of silicon, is bonded to the transition layer 48. In this method, the transition layer 48 comprises carbon and silicon, with the portion of the transition layer 48 adjacent the diamond layer 46 being comprised of substantially carbon and the portion of the transition layer 48 adjacent the wafer layer 50 being comprised of substantially silicon. With the method, sharp interfaces and poor thermal matches between the layers in the composite wafer can be minimized. As a result, the layers in the composite wafer are less likely to delaminate and the composite wafer is likely to warp or bow due to mismatched film stresses.

Abstract: A diamond wafer including a substrate and a (100) oriented polycrystalline diamond film grown on the substrate for making surface acoustic wave devices, semiconductor devices or abrasion-resistant discs. The (100) oriented film is produced by changing a hydrocarbon ratio in a material gas halfway from a higher value to a lower value. The wafer is monotonously distorted with a distortion height H satisfying 2 .mu.m.ltoreq..vertline.H.vertline..ltoreq.150 .mu.m. The film is polished to a roughness of less than Rmax50 nm and Ra20 nm.