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Shijiazhuang, China

Jiang C.-S.,University of Science and Technology Beijing | Liu Z.,University of Science and Technology Beijing | Guo S.-B.,University of Science and Technology Beijing | Li X.-J.,University of Science and Technology Beijing | And 3 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2010

Diamond film was prepared by DC arc plasma jet method and the effect of change of deposition temperature in the process of deposition on formation of dark feature was investigated. The result indicates that the lower density of dark feature is observed in the diamond film under stable temperature conditions. When the deposition temperature changes significantly, a large number of dark feature is formed. The cause is that penetration twins form when the deposition temperature is changed in the process of diamond film deposition. The pathway between reactive gas and micro-zones of grain boundaries will be blocked when formation of penetration twins on surface of the diamond films, and as a result of this, the dark feature, which is a type of growth defects, is produced. Source

Luo T.-L.,Hebei Institute of Laser
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2014

To facilitate the measuring, recording and communicating of the light transmittance of diamond films, the technical problems of the transmittance measurement of diamond films with a camera was studied. The principle was to get a quick reference table of the diamond films transmittance with a differential of 20% and 25 grades by the camera's sensitivity, aperture, shutter speed. The transmittance grade and transmittance ratio of the diamond film could be known by looking up the quick reference table after measuring the shutter speed. The representation of the light transmittance was suitable for multi-scatter points, single-parameter, 25-grade, plane coordinate graphic method and single-scatter point, multi-parameter, related information polynomial method. The method was rapid, convenient, simple and reliable with no use of large-scale equipment and maintaining the integrity of the diamond films. The problem of how to measure, characterize and grade a whole diamond film was solved successfully by this method. ©, 2014, Zhengzhou Institute of Abrasives Grinding. All right reserved. Source

Feng Z.,China Institute of Technology | Wang J.,China Institute of Technology | He Z.,China Institute of Technology | He Z.,Hebei University of Technology | And 7 more authors.
Science China Technological Sciences | Year: 2013

Metal-semiconductor field effect transistors (MESFETs) were fabricated on H-terminated polycrystalline diamond. The DC characteristics of the p-channel MESFET showed a maximum drain current density of 204 mA/mm at a gate-source voltage of -6 V, and a maximum transconductance of 20 mS/mm at a drain-source voltage of -1.5 V. The small signal S-parameters of MESFET with 2 × 100 μm gate width and 2 μm gate length were measured. An extrinsic cut-off frequency (f T) of 1.7 GHz and the maximum oscillation frequency (f max) of 2.5 GHz were obtained, which was the first report on diamond MESFETs with RF characteristics in China. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg. Source

Wang J.J.,Hebei Semiconductor Research Institute | He Z.Z.,Hebei Semiconductor Research Institute | He Z.Z.,Hebei University of Technology | Yu C.,Hebei Semiconductor Research Institute | And 8 more authors.
Diamond and Related Materials | Year: 2014

Diamond is a promising semiconductor material for high power, high frequency and high temperature electronic devices. High-purity polycrystalline diamond with large grain size has showed prominent RF properties. In this work, polycrystalline free-standing diamond film with grain size of 150 μm was grown by DC arc plasma jet technique with a growth speed as high as 20 μm/h. The prepared diamond sample showed high-purity with a (220) preferred orientation by the XRD and Raman spectra measurements. By a self-aligned process, hydrogen terminated p-type diamond MESFETs with gate length of 100 nm were fabricated on the 15 mm × 15 mm diamond film and showed good DC and RF performances with drain saturation current 225.7 mA/mm and maximum oscillation frequency (fmax) 46.8 GHz. © 2014 Elsevier B.V. Source

Liu X.-C.,Hebei Institute of Laser | Jiang L.,Hebei Institute of Laser | An X.-M.,Hebei Institute of Laser
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2015

Diamond has great potential in many areas because of its excellent physical and chemical properties. The preparation of high deposition, high quality and large area of single-crystal diamond by chemical vapor deposition has raised a hot tide. Single-crystal diamond synthesized by MPCVD technique and briefly introduces the development of CVD single-crystal diamond were summarized. Finally the application of single-crystal diamond is proposed. ©, 2015, Rengong Jingti Xuebao/Journal of Synthetic Crystals. All right reserved. Source

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