Hideo Kiyota

Synthesis of n-type semiconducting diamond film using diphosphorus pentaoxide as the doping source

An n-type semiconducting diamond film has been synthesized by the hot filament CVD method using diphosphorus pentaoxide as the doping source. The obtained film was identified as polycrystalline diamond containing few sp2 components by means of several methods including Raman spectroscopy. From measurements of the Hall effect and the Seebeck effect, the film was found to be an n-type semiconductor.

Cathodoluminescence from high‐pressure synthetic and chemical‐vapor‐deposited diamond

The nature of an UV cathodoluminescence band, which can appear in both boron‐doped high‐pressure high‐temperature (HPHT) synthetic diamond and boron‐doped diamond grown by chemical‐vapor‐deposition (CVD) techniques, is investigated. The band has a peak energy at 4.6 eV (270 nm), a full width at half‐maximum of ∼0.4 eV and at low temperatures (∼130 K) can represent the overwhelmingly dominant cathodoluminescence (CL) from selected regions of a given sample. The band has been examined from boron‐doped HPHT diamond grown from different solvent catalysts and from boron‐doped CVD diamond grown under a variety of deposition conditions. Low‐temperature spatially resolved CL imaging, using a scanning electron microscope with CL attachment, has revealed a clear growth‐sector dependence of the 4.6 eV band in HPHT diamond. Using this technique an investigation of the relationship between this band and other commonly observed CL bands has been carried out. The band has an interesting temperature dependence which is i...

Fabrication of Metal-Insulator-Semiconductor Devices Using Polycrystalline Diamond Film

Metal-insulator-semiconductor (MIS) devices have been fabricated using a polycrystalline diamond film doped with boron. The diamond film has been deposited on Si substrate by a hot-filament chemical vapor deposition method. The SiO2 film has been deposited on the diamond by a plasma-assisted CVD method and aluminum has been evaporated as a gate on the SiO2 film. The MIS capacitance was varied as a function of voltage applied between the gate and substrate. Further, the metal-insulater-semiconductor field-effect transistor has indicated transistor operation capabilities at room temperature. These results suggest a possibility that the polycrystalline diamond film can be used as an electronics material.

p‐n junction diode made of semiconducting diamond films

A diamond p‐n junction diode fabricated by the chemical vapor deposition technique, shows distinct rectification characteristics. From the electron beam induced current measurement, the existence of a depletion region or a space‐charge region around the interface between the n‐ and p‐type semiconducting diamond layers was identified.

Hall mobility and carrier concentration of boron-doped homoepitaxially grown diamond (001) films

Abstract The Hall mobility and carrier concentration of boron-doped homoepitaxially grown diamond film have been measured by the van der Pauw method. Epitaxial growth of the film has been performed on the polished (001) face of a high pressure synthetic diamond crystal by means of microwave plasma-assisted chemical vapor deposition using a gaseous mixture of hydrogen (H 2 ), methane (CH 4 ) and diborane (B 2 H 6 ). The mobility obtained was considerably higher for the films grown at low CH 4 concentrations; the highest mobility was 707 cm 2 V −1 s −1 which was obtained for the film grown at the CH 4 concentration of 1% in the present work.

Fabrication of a diamond p-n junction diode using the chemical vapour deposition technique☆

Abstract A diamond p − n junction diode has been fabricated by the chemical vapour deposition technique. Diphosphorus pentaoxide and boron trioxide were used for the doping sources for the n - and p -type layers, respectively. The diode shows distinct rectification characteristics at 300 K room temperature. This diode shows rectification even at 370 K and this result implies the possible use of diamond as a semiconductor in high temperature conditions.

Doping of diamond

Abstract Semiconducting diamond films were deposited by the conventional hot filament chemical vapour deposition technique. Boron trioxide and diphosphorus pentaoxide have been used as the dopants for p- and n-type films respectively. The films obtained were identified as diamond by means of scanning electron microscopy, electron diffraction and Raman spectroscopy. The impurity concentrations in the films were evaluated using secondary ion mass spectroscopy. The semiconducting properties of the films were confirmed by measuring the resistivity, the Hall effect and the activation energy of the conductivity.

Characterization of semiconducting diamond film and its application to electronic devices

Abstract A diamond p-n junction diode has been fabricated by the chemical vapour deposition technique. Diphosphorus pentaoxide and boron trioxide were used for the doping sources for the n- and p-type diamond films respectively. The films were identified as diamond from the results of the electron diffraction and Raman spectroscopy. The diode exhibited distinct rectification characteristics. The formation of the depletion layer was confirmed from the result of the electron-beam-induced current measurement.

Isothermal capacitance transient spectroscopy measurements on polycrystalline diamond/hydrogenated amorphous silicon heterojunctions

A deep level in boron‐doped polycrystalline diamond films located approximately 0.6 eV above the valence‐band edge has been found using isothermal capacitance transient spectroscopy (ICTS) measurements. p‐n heterojunctions between polycrystalline diamond and hydrogenated amorphous silicon were used in the study. The density and the hole‐capture cross section of the deep level traps were determined from the temperature dependence of ICTS spectra and found to be 2×1016 cm−3 and 1×10−17 cm2, respectively.

Formation of ohmic contacts on semiconducting diamond grown by chemical vapour deposition

Abstract The current-voltage (I–V) characteristics and the contact resistance Rc of Au/, Al/ and Mg/chemically vapour deposited semiconducting diamond contacts were measured. The I–V characteristics of Al/ and Mg/p-diamond contacts changed their properties from an ohmic to a rectifying nature as the resistivity of the semiconducting diamonds increased, while the Au/p-diamond contact was ohmic. An Rc of less than 103 Ω cm2 is found to be necessary to obtain the ohmic contacts on semiconducting diamonds regardless of the metal. The rough estimate of the barrier height oB was also discussed using the results of the Rc measurement.