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.
Li J.,University of Chinese Academy of Sciences |
Liu H.,University of Chinese Academy of Sciences |
Zuo Y.,University of Chinese Academy of Sciences |
Bai Y.,University of Chinese Academy of Sciences |
And 6 more authors.
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2016
As magnetron sputtering copper films would flake from silicon substrates in the ultrasonic cleaner, this paper analyzed the states of motion and stress of samples in the ultrasonic medium. By calculation, it was found that the tension-tension cycle stress caused by forced vibration was the main reason of interface damage. Then the ultrasonic mechanical model was established and the film-substrate adhesive strength was calculated. The results showed that the adhesive strength values gotten by the ultrasonic test method were in the same order of magnitude compared with that of scratch test results. In addition, this ultrasonic test method was used to test adhesion of copper films on diamond substrates. The influence of ultrasonic parameters, substrate morphology as well as composition on adhesive strength was also discussed. © All right reserved.
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.
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.
Luo T.,Hebei Institute of Laser |
Luo T.,Hebei Plasma Diamond Technology Co. |
Cai Y.,Hebei Institute of Laser |
Cai Y.,Hebei Plasma Diamond Technology Co. |
And 6 more authors.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2015
In order to improve the transparence of diamond films and the stability of technical parameters, the black defects of diamond films prepared with DC Arc Plasma Jet CVD method were investigated. The black defects after observation, analysis, measurement and comparison using several kinds of optical microscopes were classified into punctiform, massive, texture and lamellar defects. The punctiform black defects were produced by masking and scattering of light caused by granular metal impurity, carbon mass, cavity and penetrating twins in diamond films. The massive and stripped defects were produced by reflection and scattering of light caused by changes of surface angle and orientation between the crystal columns. The texture defects were produced by the stress in the diamond films. The lamellar defects were produced by absorption of light caused by conductive elements at different horizons of diamond films. The lamellar defects were the main light-blocked defects of diamond films because the existence of lamellar defects severely influenced the improvement and stability of transparence, abrasion ratio, thermal conductivity and three-point bending fracture strength of diamond films. Some ways to solve the black defects had been put forward. ©, 2015, Zhengzhou Institute of Abrasives Grinding. All right reserved.
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.
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.
Wang Z.-N.,Hebei Institute of Laser |
Wang Z.-N.,Hebei Plasma Diamond Technology Co. |
Li G.-H.,Hebei Institute of Laser |
Li G.-H.,Hebei Plasma Diamond Technology Co. |
And 5 more authors.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2011
Diamond films were deposited on Si substrate by plasma jet. The influence of size and pretreatment method of silicon wafer, as well as diamond film deposition and heat treatment on the characteristics and crack of composite substrate were investigated. The fabrication processes for the diamond film/Si composite substrates was optimized.The results showed that: the thickness of diamond film deposited on Si substrate was more than 20 μm. After polishing, the surface roughness(R a) of diamond film reached 5.2 nm. The thickness of residual diamond film was more than 10 μm, and the flatness was less than 30 μm. The indexes of composite substrates met technical requirements of electronic components.