PVD真空镀膜进程很是巨大,由于镀膜道理的差异分为许多种类,仅仅因为都需要高真空度而拥有统一名称。所以对付差异道理的PVD真空镀膜,影响匀称性的因素也不尽沟通。而且匀称性这个观念自己也会跟着镀膜标准和薄膜身分而有着差异的意义。 薄膜匀称性的观念: 1.厚度上的匀称性,也可以优先略为粗拙度,在光学薄膜的标准上看(也就是1/10波长作为单元,约为100A),真空镀膜的匀称性已经相当好,可以轻松将粗拙度节制在可见光波长的1/10范畴内,也就是说对付薄膜的光学特性来说,真空镀膜没有任何障碍。 可是假如是指原子层标准上的匀称度,也就是说要实现10A甚至1A的外貌平整,是此刻真空镀膜中主要的技能含量与技能瓶颈地址,详细节制因素下面会按照差异镀膜给出具体表明。 2.化学组分上的匀称性: 就是说在薄膜中,化合物的原子组分会由于标准过小而很容易的发生不匀称特性,SiTiO3薄膜,假如镀膜进程不科学,那么实际外貌的组分并不是SiTiO3,而大概是其他的比例,镀的膜并非是想要的膜的化学身分,这也是真空镀膜的技能含量地址。 3.晶格有序度的匀称性: 这抉择了薄膜是单晶,中岳钛金,多晶,非晶,是真空镀膜技能中的热点问题,详细见下。 主要分类有两个大种类: 蒸发沉积镀膜和溅射沉积镀膜,详细则包罗许多种类,包罗真空离子蒸发,磁控溅射,MBE分子束外延,溶胶凝胶法等等 一、对付蒸发镀膜: 一般是加热靶材使外貌组分以原子团或离子形式被蒸发出来,而且沉降在基片外貌,通过成膜进程(散点-岛状布局-迷走布局-层状发展)形成薄膜。 厚度匀称性主要取决于: 1、基片质料与靶材的晶格匹配水平 2、基片外貌温度 3、蒸发功率,速率 4、真空度 5、镀膜时间,厚度巨细。 组分匀称性: 蒸发镀膜组分匀称性不是很容易担保,详细可以调控的因素同上,可是由于道理所限,对付非单一组分镀膜,蒸发镀膜的组分匀称性欠好。 晶向匀称性: 1、晶格匹配度 2、基片温度 3、蒸发速率 二、.对付溅射类镀膜,可以简朴优先略为操作电子或高能激光轰击靶材,并使外貌组分以原子团或离子形式被溅射出来,而且最终沉积在基片外貌,经验成膜进程,比较终形成薄膜。 溅射镀膜又分为许多种,总体看,与蒸发镀膜的差异点在于溅射速率将成为主要参数之一。 溅射镀膜中的激光溅射镀膜pld,组分匀称性容易保持,而原子标准的厚度匀称性相对较差(因为是脉冲溅射),晶向(外沿)发展的节制也较量一般。以pld 为例,因素主要有:靶材与基片的晶格匹配水平、镀膜气氛(低压气体气氛)、基片温度、激光器功率、脉冲频率、溅射时间。对付差异的溅射质料和基片,比较佳 参数需要尝试确定,是各不沟通的,镀膜设备的优劣主要在于可否准确控温,可否担保好的真空度,可否担保好的真空腔洁净度。MBE分子束外沿镀膜技能,已经 较量好的办理了如上所属的问题,可是根基用于尝试研究,家产出产上较量常用的一体式镀膜机主要以离子蒸发镀膜和磁控溅射镀膜为主。 The process of PVD vacuum coating is very complicated. Due to the different principles of coating, there are many kinds of PVD vacuum coating. Therefore, for PVD vacuum coating with different principles, the factors affecting uniformity are not the same. And the concept of uniformity itself will be different with the coating scale and composition of the film. Concept of film uniformity: 1. The thickness uniformity, can also be interpreted as roughness, watching it on the scale of the optical thin film (that is 1/10 of a wavelength as a unit, is about 100 a), the uniformity of vacuum coating has been fairly good, easy to control the roughness of 1/10 of the visible light wavelength range, that is for the optical properties of thin film, vacuum coating without any obstacles. However, if it refers to the uniformity on the atomic layer scale, that is to say, the surface flatness of 10A or even 1A should be achieved, which is the main technical content and technical bottleneck in vacuum coating. Specific control factors will be explained in detail according to different coating. 2. Uniformity of chemical components: Atomic group branch is in the film, compounds because of the scale is too small and it is easy to produce uneven characteristics of SiTiO3 film, if the coating process is not scientific, so on the surface of the component is not actual SiTiO3, and may be in proportion to the other, the plating film is not want the chemical composition of the membrane, it is also the technical content of vacuum coating. 3. Uniformity of lattice order: This determines that the film is monocrystalline, polycrystalline, amorphous, is a hot issue in vacuum coating technology, see the details below. There are two main categories: Evaporation deposition and sputtering deposition, including a number of specific types, including vacuum ion evaporation, magnetron sputtering, MBE molecular beam epitaxy, sol-gel method, and so on 1. For evaporation coating: Generally, surface components are vaporized by heating the target material in the form of atomic groups or ions, and settle on the substrate surface to form a thin film through the film-forming process (scatter - island - vagal - lamellar growth). Thickness uniformity mainly depends on: 1. Lattice matching degree of substrate material and target material 2. Substrate surface temperature 3. Evaporation power and rate 4. Vacuum degree 5, coating time, thickness. Composition uniformity: The uniformity of evaporation coating components is not easy to ensure, the specific factors can be adjusted as above, but due to the principle of limitation, for non-single component coating, evaporation coating components uniformity is not good. Crystallographic uniformity: 1. Lattice matching degree 2. Substrate temperature 3. Evaporation rate For sputtering coating, it can be simply understood as bombarding the target material with electrons or high-energy laser, and making surface components sputter out in the form of atomic groups or ions, and finally deposit on the substrate surface, undergo the film formation process, and finally form a film. Sputtering coating is divided into many kinds, in general, and evaporation coating difference is that the sputtering rate will become one of the main parameters. In the sputtering coating, the composition uniformity of PLD is easy to maintain, while the thickness uniformity of atomic scale is relatively poor (because it is pulse sputtering), and the growth control of crystal orientation (outer edge) is relatively general. With PLD For example, the main factors are: the lattice matching degree of target material and substrate, coating atmosphere (low-pressure gas atmosphere), substrate temperature, laser power, pulse frequency, sputtering time. For different sputtering materials and substrates, the best The parameters need to be determined experimentally and are different. The quality of coating equipment mainly depends on whether it can accurately control the temperature, ensure a good vacuum degree, and ensure a good vacuum cavity cleanliness. MBE molecular beam outer edge coating technology, has been The above problems are well solved, but basically used for experimental research, industrial production is more commonly used in the integrated coating machine mainly ion evaporation coating and magnetron sputtering coating.