A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.

A method for coating temperature-sensitive substrates with polycrystalline diamond by a hot-wire CVD method, in which hydrogen and at least one carbon carrier gas are fed into a coating chamber. The fed gases are split at an electrically heated wire in such a way that carbon is formed and deposits on the temperature-sensitive substrate in the form of the diamond modification thereof. The substrate is arranged in the coating chamber, which is at a reduced pressure, and electrical power to electrically heat the wire is adjustable. The method is performed cyclically in respect of the electrical power that is fed to electrically heat the wire. A basic power is fed as lower threshold value for a predetermined time (basic load phase) and is increased for a further predetermined time to a maximum power as an upper threshold value (pulse phase) and is then reduced again to the basic power.

Disclosed herein is a transparent glass system that includes an optical grade silicon substrate, and a nanocrystalline diamond film on the silicon substrate, the diamond film deposited using a chemical vapor deposition system having a reactor in which methane, hydrogen and argon source gases are added. Further disclosed is a method of fabricating transparent glass that includes the steps of seeding an optical grade silicon substrate and forming a nanocrystalline diamond film on the silicon substrate using a chemical vapor deposition system having a reactor in which methane, hydrogen and argon source gases are added.

A diamond coating includes a first diamond layer made of minute diamond particles and a second diamond layer made of coarse diamond particles: in a flank-face side diamond coating, a mean coat thickness d2 is not less than 3 m and not more than 25 m, a first diamond layer is formed on a surface side and a second diamond layer is formed on a tool base side: a rake-face side diamond coating is in a smaller range of 50 m or 1/10 of a tool diameter from a tip of a base cutting-edge part; in the rake-face side diamond coating, a mean coat thickness d1 is a smaller one in a range not less than 0 m and not more than 5.0 m or a range less than d2: and a boundary part between the first diamond layer and the second diamond layer.

A semiconductor substrate according to the present invention includes a nitride semiconductor layer 203, an amorphous semiconductor layer 205 formed on one main surface side of the nitride semiconductor layer 203, a high-roughness layer 206 which is a semiconductor layer formed on the amorphous semiconductor layer 205 and has a surface roughness larger than the amorphous semiconductor layer 205, and a diamond layer 207 formed on the high-roughness layer 206. Damage to the nitride semiconductor layer can be reduced in forming the diamond layer on the nitride semiconductor layer and adhesion between the layers can be increased.

A diamond-coated tool includes: a substrate; and a diamond layer that coats the substrate, wherein the diamond layer includes a first region that is in contact with the substrate, the first region includes a region S1 surrounded by an interface P between the substrate and the diamond layer and an imaginary plane V1 separated from the interface P by a distance of 2 m, and the region S1 has crystal grains grown in random directions.

Improved thin film coatings, cutting tool materials and processes for cutting tool applications are disclosed. A boron-doped graded diamond thin film for forming a highly adhesive surface coating on a cemented carbide (WCCo) cutting tool material is provided. The thin film is fabricated in a HFCVD reactor. It is made of a bottom layer of BMCD in contact with a surface layer of the cemented carbide, a top layer made of NCD and a transition layer with a decreasing concentration gradient of boron obtained by changing the reaction conditions through ramp up option in hot filament CVD reactor. The top layer has a low friction coefficient. The bottom layer in the coating substrate interface has better interfacial adhesion through cobalt and boron reactivity and decreased cobalt diffusivity in the diamond. The transition layer has minimized lattice mismatch and sharp stress concentration between the top and bottom layers.

The present disclosure provides methods for forming diamond nanostructures and diamonds from amorphous carbon nanostructures in ambient temperature and pressure by irradiating carbon nanostructures to an undercooled state and quenching the melted carbon to convert a portion of the nanostructure into diamond.

An object is to provide a technology capable of suppressing a crack of a crystalline nitride layer which is generated due to a stress caused by difference in thermal expansion coefficients between a crystalline nitride and diamond. A semiconductor device includes a crystalline nitride layer, a structure containing silicon, and a diamond layer. The structure is disposed on a first main surface of the crystalline nitride layer. The diamond layer is disposed at least on a lateral portion of the structure and has a void between the diamond layer and the first main surface of the crystalline nitride layer. The void is a stress absorbing space, for example.