Фазовая диаграмма системы Au-Si

К оглавлению: Другие диаграммы (Others phase diargams)

Au-Si (Gold-Silicon) H. Okamoto and T.B. Massalski The equilibrium phases of the Au-Si system are (1) the liquid, L; (2) the fcc terminal solid solution, (Au), with limited solubility of Si (less than 2 at.%) ; and (3) the C (diamond)-type cubic terminal solid solution, (Si), with negligible solubility of Au (~2 <291> 10<310>4 at.%). Thermodynamic data obtained at relatively high temperatures (above approximately 1100 C) describe the phase diagram quite accurately. Optimization incorporating the experimental liquidus data further improves this accuracy. The present diagram is based primarily on a review of the work of [67Che], [67Ger], [75Ana], [75Pre], and [78Cas]. Amorphous phases have been observed in a wide composition range (~9 to 91 at.% Si), particularly if a very high quenching rate (~1010 C/s) is achieved by such means as laser pulse heating and quenching. Vapor deposition also yields amorphous phases, but in a slightly narrower composition range. Metastable crystalline structures can be obtained either through annealing of amorphous alloys above the amorphous-to-crystalline transition temperature or through quenching of liquid alloys to below the crystal-forming temperature at moderate quenching rates (~103 to 106 C/s). The practical limitation of the quenching rate attainable in bulk materials tends to limit the formation of metastable phases. Although this difficulty may be eliminated to a large extent in thin films prepared by vapor deposition, or sputtering, the specific conditions on the surface may induce characteristic crystalline structures inherent only to surface conditions. Transition temperatures are also affected by different specimen preparation methods. Editor's note: A thermodynamic model proposed by [89Che] agrees well with the experimental phase diagram. 67Che: H.S. Chen and D. Trunbull, J. Appl. Phys., 38(9), 3646-3650 (1967). 67Ger: W. Gerlach and B. Goel, Solid State Electron., 10, 589-592 (1967). 75Ana: R.P. Anantatmula, A.A. Johnson, S.P. Gupta, and R.J. Horylev, J. Electron. Mater., 4(3), 445-463 (1975). 75Pre: B. Predel and H. Bankstahl, J. Less-Common Met., 43(1/2), 191-203 (1975) in German. 75Cas: R. Castanet, R. Chastel, and C. Bergman, Mater. Sci. Eng., 32(1), 93-98 (1978) in French. 89Che: P.Y. Chevalier, Thermochim. Acta, 141, 217-226 (1989). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 4(2), Sep 1983. Complete evaluation contains 4 figures, 9 tables, and 78 references. 1