(1. New Energy Source Institute, Shenyang Institute of Engineering, Shenyang 110136, China;2. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China)
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BCN Composited BCN/carbon fibers prepared by RF magnetron sputtering deposition
(1. New Energy Source Institute, Shenyang Institute of Engineering, Shenyang 110136, China;2. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China)
In nature, the diamond is the hardest materials, but it is easy to be oxidated in the high temperature, so it can’t be used to make cutting tools under the nature conditions. Cubic boron nitride has many excellent properties, but its internal stress is large, which largely affects its development in the industrial production. People expect to create a new ternary compound boron carbon and nitrogen material, and hope that the compound has the advantages of two substances original without their shortcomings. Boron carbon nitride films were deposited onto silicon substrates by medium frequency magnetron sputtering from graphite and boron targets with Ar and N2as feedstock. By changing sputtering power of graphite target amorphous B-C-N thin films were synthesized on silicon substrate. The chemical bonding states, structure and morphology of B-C-N films were investigated by FTIR, AFM, and XRD analysis.
B-C-N film; magnetron sputtering; substrate; targets
Since the early eighties, Matsumoto and otherchemists successful synthesis diamond films by vapor deposition (CVD) techniques at low temperature and pressure conditions. The researchers have made great progress on synthetic diamond films in various countries by magnetron sputtering technology. However, due to poor thermal stability of diamond, it will be oxidized when it is heated in air to 600 ℃, and easily reacts with the iron group metals[1]. Thus Diamond role is extremely limited in the processing of the steel material, it is essential that synthetic the new diamond superhard materials close to or above diamond hardness.
Cubic boron nitride (c-BN) molecular structure, physical properties and synthesis methods are all very similar to diamond, its hardness second only to diamond, and its thermal stability and chemical stability are better than diamond, suitable for processing iron group metals. Thus recent c-BN film development is very rapid. Ternary BCN compounds have similar hexagonal and cubic BN structure. Hexagonal BCN (h-BCN) nature is between graphite and hexagonal BN (h-BN), a semiconductor or a semi-metal, and by changing the atomic composition band gap and semiconductor properties can also be adjusted; cubic BCN properties is similar to diamond and cubic BN, but it has better high temperature, oxidation, and chemical inertness than diamond; higher hardness and wear resistance than c-BN, is a new type of super-hard materials[2].
Special electrical, optical, thermal and mechanical properties of BCN material may be used as new high-temperature semiconductors, laser diodes, laser detectors, catalysts, electrode materials, molecular sieves, high-quality cutting tools, wear-resistant materials, corrosion protection layer materials widely. Therefore, the synthesis and characterization of BCN new materials has become one of most active research areasin the world. The researchers choose different materials and used a variety of synthetic methods for preparing BCN compounds of various components and structures.
Magnetron sputtering is one of the physical vapor depositions. Magnetron sputtering introduce magnetic field in the target cathode surface and make use of the magnetic field of a charged particle constraints to enhance plasma density in order to increase the sputtering rate.
Fig.1 JEPG450 R.f. magnetron sputtering equipment
This experiment equipment is adopted in the experiment by thechinese academy of sciences Shenyang scientific instrument development center Co.,LTD. Production of JEPG450 type high vacuum rf magnetron sputtering. The experiment equipment is mainly composed of vacuum system (sputtering chamber), the cooling system (circulating water), power supply and control system. As can be seen from the Fig.1.
The experiment studiedBCN film structural changes by changing graphite target power. Graphite target power adjustment as shown in Table 1.
Table 1 range of key experimental parameters
Fig.2 XRD spectra of silicon substrate and B-C-N thin films
As can be seen from the Fig.2. The pattern displayed no peaks in addition to the base peak in the range of 2θ(20°~80°), indicating that these BCN films are amorphous, which almost identical results with Xiangyang Chen[3]and all researchers. Some people think that the main reason is low thermally driven energy of atomic nucleation and isolated[4].
2.2 Fourier transform infrared spectroscopy (FTIR) analysis results
Fig.3 IR spectra of B-C-N films synthesized by changing the sputtering powers of graphite targets
IR spectra of B-C-N films synthesized by changing the sputtering powers of graphite targets are shown in Fig.3. When boron target power is 130 W, the graphite target power is 50 W,100 W,150 W respectively. From the FTIR spectra of the samples, there are two obvious absorption peaks at 2 200 cm-1and 1 600 cm-1position. The absorption peaks at around 1 100 cm-1,1 300 cm-1,1 400 cm-1and 1 600 cm-1are attributed to the B-C[5], C-N[6], B-N,C=C and C= N[7], respectively. The broad absorption peaks at 2 200 cm-1can be classified as carbon and nitrogen triple bond. And we can observe that the absorption peak intensity at 2 200 cm-1and 1 600 cm-1position will enhance with increasing graphite target sputtering power. With increasing power of graphite target, it is conducive to the formation of chemical bonds in the film. And three kinds of atoms achieve atomic scale compound.
2.3 Analysis results atomic force microscopy (AFM) analysis results
The AFM images of those samples are shown in Fig.3. In order to further analyze the surface morphology and surface roughness of the sample, we tested films by AFM. Shown in Fig.4, at room temperature graphite sputtering power is 50 W,100 W,150 W, respectively; the scanning area is 2 m×2 m. We can see that with increasing power of graphite target, the surface morphology of the films become more compact and smaller roughness, root mean square (RMS) roughness was 2.89 nm, 2.56 nm, 1.65 nm.
(1)—50 W; (2)—100 W; (3)—150 W respectively.
Fig.5 The surface RMS roughness of films with different graphite sputtering power
The surface RMS roughness of films with different graphite sputtering power are shown in Fig.5. With the increase of sputtering power graphite, carbon atoms energy also increases accordingly, which means carbon atoms have higher kinetic energy. When they get to the substrate, they have a higher surface mobility, which could help increase the membrane surface roughness.
2.4 Steps instrument analysis results
Fig.6 Deposition rate of the B-C-N thin films synthesized by changing the sputtering powers of graphite targets
We take average, each sample tested three times, respectively is 518 nm,632 nm,831 nm. Common sputtering 2 h, so the growth rate is 4.32 nm/min,5.27 nm/min,6.93 nm/min respectively. Deposition rate of the B-C-N thin films synthesized by changing the sputtering powers of graphite targets are shown in Fig.6. With the change of graphite target power, film thickness and deposition rate increase. This is due that with the increase of graphite target power per unit time out of the sputtering target material yield also increased, so the film thickness and deposition rate is increasing trend.
許多客觀問題是不可避免的,學(xué)生之間存在個體差異這是每位教育工作者都會面臨的問題,學(xué)生之間的能力差距往往也是培養(yǎng)學(xué)生解決問題能力的難點。面對這種情況,教師應(yīng)該懂得從不同的角度去開導(dǎo)學(xué)生,利用層次化教學(xué),實現(xiàn)因材施教。落實到實際教學(xué)中,教師應(yīng)該針對具體知識點從不同角度進行提問,根據(jù)學(xué)生的實際情況,讓學(xué)生解決符合自身能力水平的問題,激發(fā)學(xué)生數(shù)學(xué)學(xué)習(xí)的自信,享受解決問題的成就感。如果學(xué)生接觸不適合自身水平的問題,就可能產(chǎn)生迷茫的心理,不知道接下來所要努力的方向,這對學(xué)生的發(fā)展是極其不利的。
FTIR spectra reveal that all these synthesized B-C-N films are atomic-level hybrids composed of B, C and N atoms, when we use the graphite target as a carbon source. With increasing power of graphite target, it is conducive to the formation of chemical bonds in the film; the surface morphology of the films becomes more compact and smaller roughness.
This work was supported bythe ministry of education key laboratory under Grant LABKF1406, “Research on properties regulation of InN films grown on free-standing diamond substrates with low temperature ECR-PEMOCVD” and by education department of Liaoning province “Research on properties of InN films grown on free-standing diamond substrates with low temperature ECR-PEMOCVD”.
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[2]CHEN Youming, YANG Shengrong, ZHANG Junyan. The influence of processing gas on the mechanical properties of sputtered B-C-N-H films[J]. Appl Surf Sci, 2009,255(20):8575-8581.
[3]CHEN Xiangyang, WANG Zenghui, MA Shengli. Microstructure and tribological properties of ternary BCN thin films with different carbon contents[J]. Diam Relat Mater, 2010,19(7):1225-1229.
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[5]KIM D H, BYON E, LEE S, et al. Characterization of ternary boron carbon nitride films synthesized by RF magnetron sputtering[J]. Thin Solid Films, 2004,447/448(3):192-196.
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1673-5862(2015)03-0333-04
WANGJian1,ZHANGDong1,2,WANGXiaowen1,ZHAOYan1,LIYucai1,WANGGang1,WANGBaoshi1,GUORui1,SONGShiwei1,DINGYanbo1,LIULiying1,WANGHan1
射頻磁控濺射沉積系統(tǒng)制備BCN薄膜的研究
王 健1, 張 東1,2, 王曉文1, 趙 琰1, 李昱材1, 王 剛1,王寶石1, 郭 瑞1, 宋世巍1, 丁艷波1, 劉莉瑩1, 王 晗1
(1. 沈陽工程學(xué)院 新能源學(xué)院, 沈陽 110136; 2. 大連理工大學(xué) 物理與光電工程學(xué)院, 遼寧 大連 116024)
在自然界中,金剛石是最硬的一種材料,但把金剛石高溫暴露在空氣中時變得容易被氧化,所以在該條件下它不能用來做成切割工具。立方氮化硼有許多優(yōu)異的特性,但它的內(nèi)應(yīng)力比較大,很大程度上影響了它在工業(yè)生產(chǎn)上的發(fā)展。人們期望能夠合成出一種新的三元化合物硼碳氮材料,并且希望這種化合物既具有金剛石和c-BN的優(yōu)點而且還能克服2種物質(zhì)原有的缺點。采用射頻磁控濺射方法,以石墨靶材和甲烷氣體作為碳源,通過調(diào)控石墨靶功率在硅基片上沉積非晶B-C-N薄膜。利用傅里葉變換紅外光譜(FTIR),原子力顯微鏡(AFM),X射線衍射(XRD),臺階儀等表征手段,分別對B-C-N薄膜的表面形貌粗糙度、成鍵、沉積速率進行分析。
CN薄膜; 磁控濺射; 基片; 靶材
O469 Document code: A
10.3969/ j.issn.1673-5862.2015.03.004
Received date: 2015-06-20.
Supported: Project supported by the Key Laboratory Project of Ministry of Education(LABKF1406).
Biography: WANG Jian(1985-), male, was born in Yingkou city of Liaoning province, instructor of shenyang institute of engineering, master.