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

点击翻译按钮获取中文摘要

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