A single-crystal diamond includes n types of regions different in total concentration of an impurity, the n types of regions being observed in an observed surface being in parallel to a (110) face. Each of the n types of regions has an area not smaller than 0.1 m.sup.2. At least one of a first line, a second line, and a third line on the observed surface crosses a boundary between the n types of regions at least four times. The first line, the second line, and the third line are in parallel to a <110> direction and have a length of 1 mm. A midpoint of the first line corresponds to the center of gravity of the observed surface. The second line and the third line are distant from the first line by 300 m in a <001> direction and a <001> direction, respectively.

Apparatuses and methods are provided for manufacturing diamond electronic devices. The apparatus includes a base comprising a water-block and a cover that at least partially covers the water-block. The apparatus includes a sample stage disposed on the base. The apparatus further includes a sample holder disposed on the sample stage and configured to accept a diamond substrate. The apparatus includes controlled thermal interfaces between water-block, sample stage, sample holder and diamond substrate.

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.

Apparatuses and methods are provided for manufacturing diamond electronic devices. The apparatus includes a base comprising a water-block and a cover that at least partially covers the water-block. The apparatus includes a sample stage disposed on the base. The apparatus further includes a sample holder disposed on the sample stage and configured to accept a diamond substrate. The apparatus includes controlled thermal interfaces between water-block, sample stage, sample holder and diamond substrate.

A first diamond layer made of polycrystalline diamonds and doped with foreign atoms, is arranged on a metal surface of a machining tool, and is used to detect the degree of wear of an undoped polycrystalline second diamond layer, which is arranged on the doped diamond layer and forms a functional region of the machining tool, wherein at least one physical parameter is detected continuously or periodically during operation of the tool, and wherein a change in the parameter indicates the degree of wear of the undoped second diamond layer. The doped diamond layer forms an intelligent stop layer for the tool because as a result of change in the transition from the undoped to the doped layer, the conductivity of the system changes, for example, and this change can be used to form a stop signal for the machine drive before the tool and the machined workpiece are damaged.

A diamond substrate according to an embodiment includes a diamond layer including at least one first element selected from the group consisting of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi), the number of threefold coordinated atoms of the at least one first element in the diamond layer being larger than the number of fourfold coordinated atoms of the at least one first element in the diamond layer, a surface of the diamond layer having an off angle of 10 degrees or less with respect to a (111) face.

A method of fabricating a polycrystalline CVD synthetic diamond wafer is disclosed. A first polycrystalline CVD synthetic diamond wafer is grown using a CVD process to a first thickness on a substrate. A second smaller wafer is cut from the polycrystalline CVD synthetic diamond wafer. The second smaller wafer is located on a carrier, and further polycrystalline CVD synthetic diamond material is grown on the second smaller wafer to a second thickness to give a polycrystalline CVD synthetic diamond material having a total thickness of the combined first and second thicknesses.

Disclosed are a method of manufacturing a diamond electrode by a chemical vapor deposition (CVD) process, and a diamond electrode manufactured by the method. The method of manufacturing the diamond electrode includes: introducing a carbon source gas to form niobium carbide (NbC) on a niobium substrate, immediately before depositing an electrically conductive diamond layer on the substrate by a hot-filament chemical vapor deposition (HFCVD) process; and depositing electrically conductive diamond layers on the substrate by two or more separate processes. Accordingly, a pinhole present during deposition of the electrically conductive diamond layer is filled such that the contact between an electrolyte and the substrate in an electrolytic environment will be minimized so as to retard the corrosion of the substrate, thereby providing a diamond electrode having a long life span.

Provided are conductive diamond particles including: particulate bases; and boron-doped diamond films on at least part of surfaces of the particulate bases, wherein an average particle diameter of the conductive diamond particles is greater than 0.5 micrometers, and wherein in Raman spectrum measurement of the conductive diamond particles at an excitation wavelength of 532 micrometers, a ratio of an intensity of the conductive diamond particles at 1,580 cm.sup.1 to an intensity of the conductive diamond particles at 1,332 cm.sup.1 is less than 0.090.

A capacitor comprises a stack of layers made of a semiconductor material having a band gap energy greater than 2.3 eV, the stack of layers comprising: an electrically insulating intermediate layer having a resistivity greater than 10 kohm.Math.cm and comprising n- or p-type deep dopants producing energy levels more than 0.4 eV from the conduction band or the valence band of the semiconductor material, two contact layers having a resistivity less than or equal to 10 kohm.Math.cm and comprising dopants of a type opposite to that of the deep dopants of the intermediate layer, the two contact layers being arranged on either side of the intermediate layer to form two pin junctions.