https://www.jpcomplex.ir/Content/media/image/2013/08/772_orig.pdf

Electrochemical technologies in wastewater treatment

Electronic applications of semiconductor diamonds are addressed. Doping and electrical properties of these films, formation of low-resistive 'ohmic' contacts, surface modification methods, and experimental device applications are discussed. Of particular interest are high-temperature (300 degrees C) MOSFETs and metal contacts to CVD (chemical vapor deposition) diamond films which were used to fabricate high-temperature (580 degrees C) Schottky diodes, rudimentary MESFETs, and blue light-emitting diodes (LEDs). The status of the emerging technology is reviewed with an emphasis on the areas of current research activity. >

The electrical properties and device applications of homoepitaxial and polycrystalline diamond films

To date, the only dopant available for bulk diamond with good controllability is boron, which acts as an acceptor and can be incorporated in relatively high concentrations, allowing the design of devices for electronic applications. This paper summarizes data on doping procedures and on optical and electrical properties.

https://iopscience.iop.org/article/10.1088/0268-1242/18/3/303/pdf

The boron acceptor in diamond

Diamond is a unique material with several outstanding physical and chemical properties. It has the highest thermal conductivity at room temperature and it is transparent from the UV to the far IR. Furthermore it has the highest hardness, the highest Young's modulus and it is chemically inert and radiation hard. These and other properties of diamond are of great interest for various commercial applications. Much progress has been made in the last decade to produce diamond with chemical vapour deposition (CVD) techniques. Today, CVD diamond plates of more than 10 cm in diameter and more than 1 mm in thickness are commercially available whose properties, especially the optical and thermal ones, are comparable to the best single-crystal diamonds. In this overview, the historical development of CVD diamond deposition with the main focus on the most important techniques, hot-filament and microwave assisted CVD, will be resumed. We describe the control of structural and morphological properties during the deposition which is a prerequisite of oriented growth and the doping of diamond which is needed for semiconductor and sensor applications. The second part of this overview will discuss optical, thermal, thermomechanical and electronic properties of single-crystal diamond and CVD diamond. Finally, we give a description of several applications such as IR windows, heatspreaders, temperature sensors, piezoresistive sensors, diodes and transistors.

https://iopscience.iop.org/article/10.1088/0034-4885/61/12/002/pdf

Growth and application of undoped and doped diamond films

The effects of heteroatom addition on the nucleation of solid carbon in a low‐pressure plasma reactor were investigated. Silane or diborane were added to acetylene mixed in hydrogen or argon. Oxygen was added to some of the diborane containing gas mixtures. Silane containing mixtures resulted in powder comprised of weakly bonded amorphous hydrogenated carbon‐silicon material. The addition of diborane resulted in substantial production of diamond particles, 5 to 450 nm in diameter, under the conditions that show no diamond formation without diborane present. The observed yield of the oxidation‐resistant powder produced in boron‐containing mixtures reached 1.3 mg/h with the linear growth rates of diamond particles on the order of 102–104 μm/h. Implication of these results to interstellar dust formation is discussed.

Induced nucleation of diamond powder

The electrical conductivity of diamond thin films produced by the hot‐filament technique is found to increase when diborane is incorporated in the precursor gas mixture. The combination of well‐defined bulk conductivity measurements with quantitative secondary‐ion mass spectrometry and Raman spectroscopy shows that the conductivity increase is associated with atomic boron doping and rules out any significant role for a graphitic‐type component.

Boron doping of diamond thin films

The thermomechanical properties of amorphous glow‐discharge deposited silicon and silicon oxide films were measured as a function of film composition. Hydrogenated amorphous silicon films, deposited at 250 °C with a density of 2.0 g/cm3 and 20 at. % of hydrogen, exhibit a linear thermal expansion coefficient of about 4.4×10−6/°C and a biaxial elastic modulus of 150 GPa. The expansion coefficient of plasma‐deposited silicon oxide films shows a systematic dependence on the fabrication conditions and ranges from about 10−5/°C to negative values. Strong correlations between the hydrogen concentration of the films, the film density, and thermal expansion coefficient were observed and are discussed. The biaxial elastic modulus of the oxide films is not strongly dependent on the gas ratio and is about 40 GPa, substantially smaller than the values obtained for thermally grown oxides. These differences are attributed to the effect of network terminations by hydrogen and −OH groups.

Thermal expansion and elastic properties of plasma‐deposited amorphous silicon and silicon oxide films

The conductivity of a-Si:H multilayers consisting of alternating boron and phosphorus doped layers has been studied as a function of sub-layer thickness. The planar and perpendicular dark conductivity is compared with theoretical analysis of space-charge doping in these structures and this effect is found to dominate the transport as the sub-layer thickness is reduced below a critical value.

D. Kuhman

Papers

Boron doping of diamond thin films

Thermal expansion and elastic properties of plasma‐deposited amorphous silicon and silicon oxide films

Planar and Perpendicular Conductivity of Doping Modulated Amorphous Silicon Multilayers