Silicides formation

Palladium and platinum are also used as carrier lifetime controllers in Si. Pd creates an electron trap at Ec - 0.22 eV and a hole trap at Ev + 0.32 eV in Si (Chen and Milnes, 1980). Pt induces a single electron trap at Ec + 0.28 eV (Chen and Milnes, 1980). All of these levels are passivated by atomic hydrogen (Pearton and Haller, 1983) suggesting that hydrogen might be profitably used during silicide formation to passivate electrically active levels near the silicon-silicide interface. 

Miodownik et al. 1979, Watkin 1979). Irradiation can cause void-swelling, suppression of a formation in stainless steels and non-equilibrium precipitation of silicides. These phenomena are complex and occur by a combination of thermodynamic and kinetic effects. However, it was shown by Miodownik et al. (1979) that a thermodynamic analysis could be used to good effect to rationalise the effect of radiation on silicide formation. Although the work was done for a simple alloy system, it demonstrates how thermodynamics can be used in unusual cirounstances. 

Lewis base adducts, 25 64, 68-69 metal exchange reactions, 25 57 NMR spectra, 25 93-95 pyrolysis, 25 107 silicide formation, 25 110 tetracarbonylsilyl hydride reaction with isoprene, 25 75 reductive elimination, 25 81 site, formation, ribonucleotide reductase, 43 372-375... 

Fig. 4.14 (a) A few atomically resolved images of surfaces of WSi2 where Si atoms arc invisible. In tungsten silicide, only the W sublatticc is seen in the field ion image. Sec Section 4.4.2 for discussions on silicide formation. (b) Atomic structure of WSi2 crystal. 

On a metal surface, silicide layers can be formed by two methods. In the first, Si atoms are vapor deposited by heating either a well degassed silicon wafer or a silicon rod to near its melting point. In the second method the metal is heated in 10 to 50 mTorr of silane for a desired length of time, usually about 10 to 60 s at a desired temperature, usually about 300 to 700°C. The first method is better suited for studying very early stages of silicide formation, the second more convenient for growing thick layers of silicides. Chemical vapor deposition or laser enhanced chemical vapor deposition may probably be used also, but have not yet been explored. 

Defect formation due to silicide formation, reduced strength... 

Iron(III) salts, and Grignard reagent reactivity, 9, 49 Iron seleno-terephthalates, for fungus and molds, 12, 458 Iron silicides, formation, 6, 19... 

This migration of silicon from metal to oxygen will be discussed further in connexion with silicide formation in Section V,A. 

R. Pretorius. Prediction of silicide formation and stability using heats of formation // Thin Solid Films.- 1996.- V.290-291 - P.477-484. 

A.A. Naem. Platinum silicide formation using rapid thermal processing // J.Appl. Phys.- 1988.- V.64, No.8.- P.4161-4167. 

A.K. Pant, S.P. Murarka, C. Shepard, W. Lanford. Kinetics of platinum silicide formation during rapid thermal processing // J.Appl.Phys.- 1992.- V.72, No.5.- P.1833-1836. 

Silicide formation has been reviewedand the interaction between thin metal films and Si substrates is of interest for the use of silicides as ohmic or rectifying contacts and as interconnects in Si semiconductor device technology. Information about metal-silicon (M-Si) phase diagrams is also available . 

The transition metals are used as metallization layers in Si device technology Upon heating, the thin (a few thousand A thick) transition-metal layers react uniformly with the Si substrate to form a silicide. From a typical transition-metal-Si binary phase diagram (see Fig. 1), the lowest T at which a liquid appears is greater than 900°C, which is above the process T used in integrated circuit fabrication. In Si device processing, silicide formation is therefore usually a solid-phase interaction. 

Table 3. Silicide Formation Between Thin Transition-Metal Films and Silicon Substrates" ...

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