Effects of Ionized Cluster Beam Bombardment on Epitaxial Metal Film Deposition on Silicon Substrates
- PDF / 4,117,167 Bytes
- 12 Pages / 420.48 x 639 pts Page_size
- 78 Downloads / 208 Views
EFFECTS OF IONIZED CLUSTER BEAM BOMBARDMENT ON EPITAXIAL METAL FILM DEPOSITION ON SILICON SUBSTRATES Isao Yamada Ion Beam Engineering Experimental Laboratory, Kyoto University, Sakyo, Kyoto 606, Japan. ABSTRACT The effects of ion beam bombardment during ionized cluster beam (ICB) deposition of metal films on Si(lll) and Si(100) substrates have been discussed. In the case of Al deposition, films have been epitaxially deposited on Si(lll) and Si(100) substrates at near room temperature. On Si(lll) substrates, nearly perfect Al single crystal films could be formed. On Si(100) substrates, Al bicrystals have been grown epitaxially. A remarkable fact concerning these results is that the epitaxial films could be formed at nearly room temperature and on a large lattice mismatch (25%) substrate surface. Atomic resolution TEM analysis suggests that the epitaxy of Al occurs not only on Si surfaces but also at Al/Al grain boundaries. These epitaxial films exhibit extremely high thermal stability and long electromigration life time. To understand the deposition features and film characteristics, the effects of ICB bombardment on the film growth at the initial stage of the deposition and the resultant film structure have been studied. The results show that the role of very low energy ion bombardment is especially important in forming epitaxial metal films. Depositions of Au and Cu on Si substrates have also been made to understand whether ICB deposition may improve the characteristics of other metal films. Preliminary results of these film depositions are also obtained.
INTRODUCTION
Many experiments have been undertaken to prepare various kinds of films by ICB and reactive ICB depositions [l]. These experiments include the deposition of simple metals, such as Au, Cu, Pb, Ag, Al, Sb, Te and others on a range of substrates. More complicated depositions were made of intermetallic or alloy films on such alloys as CuAl, CuNi, MnBi, GdFe, PbTe, ZnPb and FeSi2 . For the case of semiconductors, depositions of Si in a range of crystalline forms from amorphous to single crystal have been made. Films of Ge, GaAs, GaP, ZnS, InSb, CdTe and Cd-Mn-Te, as well as doped semiconductors have also been deposited. Reactive ICB experiments have been performed on a wide range of oxides, nitrides, hydrides and fluorides. Several organic thin films have also been deposited by ICB at lower substrate temperature. In many cases, the films deposited by ICB and RICB depositions differed markedly from films deposited on the same materials by means of conventional evaporation or sputtering techniques. Among those results, it is especially remarkable that Al films can be epitaxially deposited on Si substrates at near room temperature by using ICB [2]. Since ICB deposition offers the capability of controlling the film structure by applying kinetic energy to the cluster beam during film deposition, the technique has a unique advantage compared to other deposition techniques. The useful kinetic energy an ion beam should have to enhance crystal growth and to prom
Data Loading...
