负偏压热灯丝CVD金刚石膜核化和早期生长的研究

NUCLEATION AND INITIAL GROWTH OF DIAMOND BY BIASED HOT FILAMENT CHEMICAL VAPOR DEPOSITION

利用扫描电子显微镜、Ｒａｍａｎ谱和Ｘ射线光电子能谱，研究了Ｓｉ衬底上热灯丝ＣＶＤ金刚石膜的核化和早期生长．在－３００Ｖ和１００ｍＡ条件下预处理１５ｍｉｎ，镜面抛光的Ｓｉ（１００）表面上金刚石核密度超过了１０９ｃｍ－２，但是核的分布极不均匀且可分为三个区域：Ａ区，边缘处以锥体为主；Ｂ区，位于边和中心之间过渡区是纳米金刚石；Ｃ区，中心处有ＳｉＣ层．无偏压下生长４ｈ后，Ａ区形成许多大而弧立的金刚石颗粒，Ｂ区成为织构金刚石膜，而Ｃ区变为含有大量缺陷的连续金刚石膜．衬底负偏压增强金刚石核化是由于离子轰击和发射电子同时作用的结果，离子流本身的不均匀导致核化的不均匀性．

Abstract  The nucleation and initial growth of diamond on Si(100) by biased hot filament chemical vapor deposition have been studied by scanning electron microscopy,Raman spectra,infrared absorption spectra and X ray photoelectron spectra.After bias pretreated for 15min at -300V and 100mA,the nucleation density was found to be over 10 10 cm -2 on mirror polished Si and was inhomogeneous,which can be divided into three regions on Si surface:A,cones at the edges;B,nanocrystalline diamond at the transition region between the edge and the centre;and C,SiC layers at the centre.The films with defects,textured films,and big discrete grains of diamond were formed at A,B,C regions respectively after 4h growth without bias.The nucleation enhancement by substrate negative bias is believed to be a combination effect of the ion bombardment and emission electron.The non uniformity of ion distribution led to an uneven nucleation on the Si substrate surface. 