Department of Applied Science for Electronics and Materials, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan.
ACS Appl Mater Interfaces. 2012 Oct 24;4(10):5249-55. doi: 10.1021/am301133d. Epub 2012 Sep 26.
Thick cubic boron nitride (cBN) films in micrometer-scale are deposited on tungsten carbide-cobalt (WC-Co) substrates without adhesion interlayers by inductively coupled plasma-enhanced chemical vapor deposition (ICP-CVD) using the chemistry of fluorine. The residual film stress is reduced because of very low ion-impact energies (a few eV to ∼25 eV) controlled by the plasma sheath potential. Two types of substrate pretreatment are used successively; the removal of surface Co binder using an acid solution suppresses the catalytic effect of Co and triggers cBN formation, and the surface roughening using mechanical scratching and hydrogen plasma etching increases both the in-depth cBN fraction and deposition rate. The substrate surface condition is evaluated by the wettability of the probe liquids with different polarities and quantified by the apparent surface free energy calculated from the contact angle. The surface roughening enhances the compatibility in energy between the cBN and substrate, which are bridged by the interfacial sp(2)-bonded hexagonal BN buffer layer, and then, the cBN overlayer is nucleated and evolved easier.
通过使用氟化学的电感耦合等离子体增强化学气相沉积 (ICP-CVD)，在没有附着力中间层的情况下，在碳化钨-钴 (WC-Co) 衬底上沉积了微米级厚的立方氮化硼 (cBN) 薄膜。由于等离子体鞘层电势控制的离子冲击能非常低（几电子伏特到 25 电子伏特左右），因此残余薄膜应力降低。采用两种类型的衬底预处理方法；使用酸溶液去除表面 Co 结合剂可抑制 Co 的催化作用并引发 cBN 形成，而机械划伤和氢等离子体蚀刻表面粗糙化则同时提高了 cBN 的深度分数和沉积速率。通过具有不同极性的探针液体的润湿性评估基底表面状态，并通过从接触角计算出的表观表面自由能进行量化。表面粗糙化增强了 cBN 和衬底之间在能量上的兼容性，它们通过界面 sp2 键合的六方 BN 缓冲层桥接，然后，cBN 覆盖层更容易成核和演变。
