Ramp-Rate Effects on Transient Enhanced Diffusion and Dopant Activation

Use of high ramp rates (>400°C/s) in rapid thermal annealing after ion implantation leads to experimentally observed improvements in junction depth and the reverse narrow-channel effect. However, a straightforward explanation for this effect has been lacking. Via modeling, we find that increasing the heating rate permits clusters with dissociation energies lower than the maximum of 3.5-3.7 eV to survive to higher temperatures. This improved survival delays the increase in Si interstitial concentrations near the top of an annealing spike, which decreases the profile spreading.

[1]  Nichols,et al.  Mechanisms of dopant impurity diffusion in silicon. , 1989, Physical review. B, Condensed matter.

[2]  Adel F. Sarofim,et al.  Activation energy distribution in temperature-programmed desorption : modeling and application to the soot-oxygen system , 1990 .

[3]  Cowern,et al.  Experiments on atomic-scale mechanisms of diffusion. , 1991, Physical review letters.

[4]  Reactions of point defects and dopant atoms in silicon. , 1992 .

[5]  Edmund G Seebauer,et al.  Quantitative extraction of continuous distributions of energy states and pre-exponential factors from thermal desorption spectra , 1994 .

[6]  P. Chi,et al.  Transient enhanced diffusion without {311} defects in low energy B+‐implanted silicon , 1995 .

[7]  Hayashi,et al.  Boron Implanted Shallow Junction Formation By High-temperature/ Short-time/high-ramping-rate(400/spl deg/C/sec) RTA , 1997, 1997 Symposium on VLSI Technology.

[8]  Optimization of RTA parameters to produce ultra-shallow, highly activated B+, BF2+, and As+ ion implanted junctions , 1998 .

[9]  Characterisation of Low Energy Boron Implantation and Fast Ramp-Up Rapid Thermal Annealing , 1998 .

[10]  Daniel F. Downey,et al.  Effects of “fast” rapid thermal anneals on sub-keV boron and BF2 ion implants , 1999 .

[11]  A. T. Fiory,et al.  Effect of ramp rates during rapid thermal annealing of ion implanted boron for formation of ultra-shallow junctions , 1999 .

[12]  Dopant dose loss at the Si–SiO2 interface , 2000 .

[13]  W. Windl,et al.  Ab initio modeling of boron clustering in silicon , 2000 .

[14]  Fumitaka Nishiyama,et al.  Lattice site location of ultra-shallow implanted B in Si using ion beam analysis , 2001 .

[15]  Fred Roozeboom,et al.  Effect of heating ramp rates on transient enhanced diffusion in ion-implemented silicon , 2001 .

[16]  R. Braatz,et al.  Parameter Sensitivity Analysis Applied to Modeling Transient Enhanced Diffusion and Activation of Boron in Silicon , 2003 .