Development of modulation reactive sputtering and its application for films with multilayr structures

在本研究中，利用计算机控制的过程气体流动系统的溅射装置，发展了一种调制反应溅射方法。该方法已被用于制备具有成分调制结构的TiOx/Ti和TiNx/Ti多层膜。在对TiOx(其中x从近0周期性地变化到2)多层膜的研究中，TiOx(x&lt；1：富金属)层和TiOx(二氧化钛)层的折射率等物理性质的差异导致了新的性质。实验中使用的靶子直径为6英寸。钛含量99.98%。通过质量流量控制器控制O2气体的质量流量，得到氧分布最佳的多层膜。在薄膜沉积过程中，Ar流量保持不变。用电容压力计测量气室内的压力，以估算薄膜沉积过程中吸气作用对氧气的消耗。质量沉积率为Me…更令人满意的是，使用了石英晶体定位监测器。用俄歇电子能谱分析了沉积薄膜的氧含量深度分布。实验结果表明，在薄膜沉积过程中，当氧气流量成正弦变化时，富金属层(TiOx中x=1)的厚度几乎是一氧化碳和二氧化钛混合层(TiOx中x=2)的6~8倍。这是由于反应溅射过程中金属模式和氧化物模式两种模式下的钛溅射产额不同所致。为了得到厚度几乎相等的富金属层和一氧化碳和二氧化硅混合层，改变了氧气流量，以延长氧化物模式下的沉积时间，缩短金属模式下的沉积时间。通过优化流量控制，得到了富金属层和一氧化碳、二氧化硅混合层厚度基本相等的薄膜。通过俄歇电子能谱深度分布分析得到的氧分布与由薄膜沉积过程中获得的氧气分压和氧气质量流量数据计算的氧气消耗量之间的关系，揭示了气体流量调制反应溅射方法的机理。结果表明，氧气流量的连续周期性而非正弦变化使薄膜中的成分呈梯度周期性分布，气体流量调节反应溅射方法有利于单靶-单一反应气体溅射制备多层膜。在TiNx/Ti(其中x从近0周期性地变化)的研究中，研究了成分调制多层膜结构对其硬度的影响。使用上述相同的设备，通过调制反应溅射沉积了成分调制的TiNx/Ti多层膜。在TiNx/Ti成分调制多层膜的形成过程中，由计算机控制的质量流量控制器自动控制氮气流量，以获得成分分布最优的薄膜。以硼硅酸盐玻璃和氧化铝平板为基板。用非压痕法测量了所制备薄膜的硬度。用俄歇电子能谱分析了所制备薄膜的成分分布。为了比较TiN单层膜和TiNx/Ti多层膜的硬度，还制备了TiN单层膜。通过改变氮气反应气体流量调制频率，在未加热的衬底上沉积了调制周期分别为5 nm、7.5 nm、10 nm和20 nm的薄膜。纳米压痕测试发现，在单层和多层薄膜中，调制频率为5 nm的薄膜具有最高的显微硬度。在这两种衬底上沉积的薄膜得到了相同的结果。研究结果表明，成分调制TiNx/Ti多层膜的硬度对调制频率的依赖性较小

In this research a modulation reactive sputtering method has been developed by using an sputtering apparatus with a computer controlled process gas flow system. The method has been applied for the formation of TiOx/Ti and TiNx/Ti multiayr film with compositionally modulated structures.In the research of TiOx (where x continuously and periodically changed from nearly 0 to 2) compositionally modulated multilayr films the differences of the physical properties such as refractive index between TIOx (x<1 : metal-rich) layrs and TiO2 (dioxide) layrs result in novel properties. The target used in the experiments was a 6inch dia. 99.98% Ti. The O2 gas mass flow rate was controlled by a mass flow contorller to obtain a multilayr film with an optimum oxygen distribution. Ar flow rate was kept constant during film deposition. The pressure in the chamber was measured with a capacitance manometer to estimate O2 gas consumption by gettering actions during film deposition. Mass deposition rate was me … More asured with a quartz-crystal eposition monitro. The oxygen content depth profiles of deposited films were analyzed by Auger Electron Spectroscopy. The experimental result showed that when the O2 flow rate was changed sinusoidally during the film deposition the metal-rich layrs (x<=1 in TiOx) became almost 6 to 8 times thicker than monoxide and dioxide mixture layrs (1<x=2 in TiOx). This is due to the diference of the Ti sputtering yield between the two sputtering modes in reactive sputtering process : metal mode and oxide mode. To obtain films with an almost equivalent thickness of metal-rich layrs and of monoxide and dioxide mixture layrs, O2 flow rate was changed to extend the time of deposition in the oxide mode and to shorten it in the metal mode. By optimizing the flow control.the films with an almost equivalent thickness of the metal-rich layrs and the monoxide and dioxide mixture layrs were obtained. The relationship between oxygen distribution obtained by AES depth profile analysis and O2 gas consumption calculated from O2 partial presure and O2 mass flow rate data obtained during the film deposition has been revealed mechanisms involved in the gas flow rate modulated reactive sputtering method. In conclusion, it has been shown that the continuous and periodical, but non-sinusoidal, change in O2 flow rate generates graded and periodical component distribution of the material in films and that tha gas rate flow rate modulated reactive sputtering method is advantageous to produce multilayr films by a single target-single reactive gas sputtering.In the research of TiNx/Ti (where x continuously and periodically changed from nearly 0 to 1) compositionally modulated multilayr films effects of multilayr strnctures of compositionally modulated TiNx/Ti films on their hardness has been investigated. Compositionally modulated TiNx/Ti multilayr films were deposited by a modulated reactive sputtering using the same apparatus described above. In the formation of TiNx/Ti compositionally modulated multilayr film a N2 gas flow rate was automatically controlled by a computer-controlled mass flow controller to produce films with an optimized composition distribution. Borosilicate glass and alumina plate were used as substrates. Hardness of prepared films were measured by a nono-indentation method. Composition distribution of prepared films was estimated by Auger electron spectroscopy. TiN singlelayr films were also deposited to compare is hardness with those of the multilayr TiNx/Ti films. By changing N2 reactive gas flow rate modulation frequency, films with a modulation period of 5nm, 7.5nm, 10nm, and 20nm were deposited onto unheated substrates. It is found by nano-indentation measurements that the films with a modulation frequency of 5nm provide highest values of micro hardness among the single layr and multilayr films. The same results were obtained for the films both deposited on the two types of substrates. The results obtained in this study indicate that the hardness of compositionally modulated multilayr TiNx/Ti films strongly depends on modulation frequency Less