Transient enhanced diffusion

The reverse time effect of diffusion was modeled by using equations 47-51. The 900 °C RTA step causes the damage anneal time, ta, to decrease relative to the 800 °C anneal. Thus, the duration of transient enhanced diffusion decreases as the RTA anneal time increases. Calculations using this model are shown in Figure 25. 

Seebauer, E.G. and Braatz, R.D. (2003a) Maximum A Posteriori Estimation of Transient Enhanced Diffusion Energetics. AIChEJ., 49, 2114-2123. 

Jung, M.Y.L., Gunawan, R., Braatz, R.D. and Seebauer, E.G. (2003) Ramp-rate Effects in Transient Enhanced Diffusion and Dopant Activation. /. Electrochem. Soc., 150, G838-G842. 

Jain, S.C., Schenmaker, W., Lindsay, R., Stak, P.A., Decoutere, S., Willander, M., Maes, H.E. Transient enhanced diffusion of boron in Si, Applied Physics Reviews. J. Appl. Phys. 91, 8919-8949 (2002)... 

H.E. Transient enhanced diffusion of boron in Si, Applied Physics Reviews. J. Appl. Phys. 91, 8919-8949 (2002)... 

The transient enhanced diffusion of B, which had been ion-implanted to a dose of 10l4/cm2, was studied by means of rapid thermal annealing and secondary ion mass spectrometry. It was found that the fraction of B diffusivity which was due to implantation damage decreased with time according to ... 

The point defect which led to the transient enhanced diffusivity was deduced to be a vacancy. It was shown that final profile broadening due to the enhanced diffusion was smaller at higher temperatures. Both Dq and L increased with increasing... 

The migration of implanted B was investigated at 800 to lOOOC by using furnace and rapid thermal annealing. The transient enhanced diffusion which was caused by implantation damage in the early phases of annealing was analyzed, and it was found that the data could be described by ... 

The driving force for the transfer process was the enhanced solubility of Br2 in DCE, ca 40 times greater than that in aqueous solution. To probe the transfer processes, Br2 was recollected in the reverse step at the tip UME, by diffusion-limited reduction to Br . The transfer process was found to be controlled exclusively by diffusion in the aqueous phase, but by employing short switching times, tswitch down to 10 ms, it was possible to put a lower limit on the effective interfacial transfer rate constant of 0.5 cm s . Figure 25 shows typical forward and reverse transients from this set of experiments, presented as current (normalized with respect to the steady-state diffusion-limited current, i(oo), for the oxidation of Br ) versus the inverse square-root of time. 

D = D° exp(-ac ), where D is the diffusion, D represents the zero-concentration limit, c is the concentration, a and v are parameters, fits the data from a wide variety of probes and matrix polymers ( ). Several theoretical justifications for this behavior have been presented (97-1011. but it is not possible to tell yet which, if any, is uniquely correct. The treatments range from simple physical considerations (98) to treatments of hydrodynsumical interaction of probe and matrix (97,991. Other more complex and general treatments (1001 do not explicitly arrive at the stretched exponential form, but do closely fit the available data. Much more work needs to be done on probe diffusion in such transient networks. Beyond enhancing the arsenal of gel characterization, the problem is quite fundamental to a number of other important processes. 

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