Study on the formation, structure and electrical properties of tungsten disilicide

In recent years, silicides have become more and more widely used as ohmic contacts, interconnects, and Schottky barriers in large scale integrated circuits. This is because aluminum used in integrated circuits has been used as an ohmic contact and interconnect metallization material. In the high temperature heat treatment process, serious diffusion phenomenon occurs, resulting in high circuit failure rate. The use of silicide is a good way to solve this problem. The silicide-silicon interface is not easily contaminated by impurities, with high reliability and repeatability. On the other hand, with the increasing integration of integrated circuits, the device size is scaled down, the lines are narrower and narrower, and the junction depth is getting shallower, making the current thickness of the thin layer of polysilicon used as the gate electrode and interconnect greatly. Increase, causing circuit power consumption and noise increase, limiting the speed of integrated circuits. Silicides, especially refractory metal silicides, have low resistivity and good high-temperature densification, thus becoming an indispensable material for integrated circuit metallization systems. Usually, a metal silicide is formed by a thermal sintering method, such as at a certain temperature for a certain period of time. Sintering a metal film of a certain thickness deposited on single crystal silicon, or co-sputtering a certain composition of metal and silicon film to form a silicide. However, the surface of the silicide formed by this thermal sintering method is rough, electric The repeatability of the characteristics is very poor. In recent years, the ion beam mixing phenomenon of semiconductor and metal systems has been extensively studied, and ion beam mixing methods have been used to form silicides of various metals. This method can not only greatly reduce metal-silicon. The effect of interface contamination on the formation of silicide, the surface and interface are flat, and the electrical properties are reproducible with silicide. It has the advantages of uniformity, controllability, stable performance, good self-alignment performance, etc. We inject people through As- The Si system forms tungsten silicide at a relatively low temperature; Tungsten silicide is a very useful refractory metal silicide. For practical applications, the structure and electricity of the formed tungsten silicide film The nature is important. This requires understanding the deposition, composition, ion beam bombardment, heat treatment, and the structure and electrical conductivity of the silicide formed by the impurity. Qualitative effects. Although some work reports the formation of WSi2 by ion beam mixing method, there are few studies on electrical properties. This work systematically studied the formation and structure of WSi2 by comparing the thermal sintering and ion beam mixing behavior of samples with different impurity contents. And electrical properties.

Study on the formation, structure and electrical properties of tungsten disilicide