納米金剛石薄膜摻硼的工藝研究
發(fā)布時間：2018-09-18 18:17
【摘要】：納米金剛石(Nano-crystalline Diamond,NCD)薄膜既擁有傳統(tǒng)微米金剛石薄膜的優(yōu)良性能,又具有晶粒細(xì)小、表面平整、膜層較薄等特性,極大地拓寬了金剛石膜的應(yīng)用領(lǐng)域。本文首先利用微波等離子體化學(xué)氣相沉積(Microwave Plasma enhanced Chemical Vapor Deposition,MPCVD)法制備高平整度的NCD薄膜,然后以其作為本征層,在其上進(jìn)行NCD薄膜的生長摻硼研究,通過對反應(yīng)氣壓、微波功率、碳源濃度和沉積時間等工藝參數(shù)的研究,探討了NCD薄膜摻硼的微觀機(jī)理。在制備高平整度NCD薄膜的研究中發(fā)現(xiàn):降低反應(yīng)氣壓可以提高NCD薄膜的形核率和二次形核率,有利于沉積表面更為平滑的NCD薄膜;當(dāng)沉積時間較短時,NCD膜層較薄,難以完全覆蓋硅襯底上的劃痕,當(dāng)沉積時間太長時,晶粒的生長模式會逐漸向柱狀轉(zhuǎn)變,形成微米級的金剛石晶粒;高的CH4濃度可提高等離子體中含碳基團(tuán)的濃度,并降低原子H的相對濃度,降低其對非金剛石相的刻蝕速率,提高金剛石的形核率和二次形核率,沉積出晶粒尺寸和表面粗糙度都比較小的NCD薄膜。通過以上研究,得到了10kW-MPCVD裝置上制備高平整度NCD薄膜的較好工藝為微波功率3.5kW、沉積時間4-6h、反應(yīng)氣壓2.5kPa、碳源濃度6%,制備出了NCD薄膜晶粒尺寸約為30nm,表面粗糙度低于20nm。在NCD薄膜的生長摻硼研究中發(fā)現(xiàn):隨著基片溫度的升高,摻硼結(jié)束后NCD薄膜的表面粗糙度和晶粒尺寸都明顯增大,在600℃到750℃的范圍內(nèi),金剛石的晶粒尺寸由55nm增大到80nm;硼烷濃度與摻硼時間對薄膜表面形貌的影響與基片溫度的影響趨勢相似。隨著摻雜過程中基片溫度的增加,摻雜后薄膜的表面電阻率也隨之變小,在750℃到850℃的溫度范圍內(nèi),其下降趨勢尤為顯著;反應(yīng)氣體中硼烷濃度對薄膜表面性能的影響與基片溫度的影響相似,但隨著硼烷濃度的增加,薄膜的表面電阻率會達(dá)到一個飽和值,該值一般在250~200??□范圍內(nèi)。此外,隨著摻雜時間的延長,摻硼后NCD薄膜的表面電阻會首先快速降低,之后保持不變。為了獲得表面平整、表面電阻較低的摻硼NCD薄膜,較好的工藝參數(shù)為:摻雜溫度700℃,乙硼烷濃度200ppm、摻雜時間15min。
[Abstract]:Nanocrystalline diamond (Nano-crystalline Diamond,NCD) thin films not only have the excellent properties of traditional micron diamond films, but also have the characteristics of fine grain, flat surface and thin film layer, which greatly broadens the application field of diamond films. In this paper, NCD thin films with high smoothness were prepared by microwave plasma chemical vapor deposition (Microwave Plasma enhanced Chemical Vapor Deposition,MPCVD) method. Then boron doped NCD thin films were grown on the substrate by microwave plasma chemical vapor deposition (Microwave Plasma enhanced Chemical Vapor Deposition,MPCVD) method. The microcosmic mechanism of boron doping in NCD thin films was investigated by studying the technological parameters such as carbon source concentration and deposition time. It is found that the reduction of reaction pressure can increase the nucleation rate and the secondary nucleation rate of NCD thin films, which is beneficial to the deposition of smoother NCD films on the surface, and the thin films can be deposited when the deposition time is short. It is difficult to completely cover the scratches on silicon substrates. When the deposition time is too long, the grain growth pattern will gradually change to columnar, forming micron diamond grains, and high CH4 concentration can increase the concentration of carbon-containing groups in plasma. The NCD thin films with small grain size and surface roughness are deposited by decreasing the relative concentration of atomic H, decreasing the etching rate of the non-diamond phase, increasing the nucleation rate and the secondary nucleation rate of the diamond. Through the above research, we have obtained that the better technology for preparing NCD thin films with high smoothness on 10kW-MPCVD device is microwave power 3.5 kW, deposition time 4-6 h, reaction pressure 2.5 KPA, carbon source concentration 6. The grain size of NCD thin films is about 30 nm and the surface roughness is less than 20 nm. It is found that the surface roughness and grain size of NCD films increase with the increase of substrate temperature, and the surface roughness and grain size of NCD films increase from 600 鈩，
本文編號：2248725
[Abstract]:Nanocrystalline diamond (Nano-crystalline Diamond,NCD) thin films not only have the excellent properties of traditional micron diamond films, but also have the characteristics of fine grain, flat surface and thin film layer, which greatly broadens the application field of diamond films. In this paper, NCD thin films with high smoothness were prepared by microwave plasma chemical vapor deposition (Microwave Plasma enhanced Chemical Vapor Deposition,MPCVD) method. Then boron doped NCD thin films were grown on the substrate by microwave plasma chemical vapor deposition (Microwave Plasma enhanced Chemical Vapor Deposition,MPCVD) method. The microcosmic mechanism of boron doping in NCD thin films was investigated by studying the technological parameters such as carbon source concentration and deposition time. It is found that the reduction of reaction pressure can increase the nucleation rate and the secondary nucleation rate of NCD thin films, which is beneficial to the deposition of smoother NCD films on the surface, and the thin films can be deposited when the deposition time is short. It is difficult to completely cover the scratches on silicon substrates. When the deposition time is too long, the grain growth pattern will gradually change to columnar, forming micron diamond grains, and high CH4 concentration can increase the concentration of carbon-containing groups in plasma. The NCD thin films with small grain size and surface roughness are deposited by decreasing the relative concentration of atomic H, decreasing the etching rate of the non-diamond phase, increasing the nucleation rate and the secondary nucleation rate of the diamond. Through the above research, we have obtained that the better technology for preparing NCD thin films with high smoothness on 10kW-MPCVD device is microwave power 3.5 kW, deposition time 4-6 h, reaction pressure 2.5 KPA, carbon source concentration 6. The grain size of NCD thin films is about 30 nm and the surface roughness is less than 20 nm. It is found that the surface roughness and grain size of NCD films increase with the increase of substrate temperature, and the surface roughness and grain size of NCD films increase from 600 鈩，
本文編號：2248725
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