In the field of device architecture in semiconductors using ion beams, the annealing procedure is indispensable to activate dopants and repairing the irradiation damage caused by ion beams. It is desirable to reduce the annealing temperature as less as possible, to suppress the diffusion of the dopants outward from a confined doped region for a fine design of the shallow junction, and also to save the power-supply to assure the sustainable future for all of us.

It is recognized that cluster beams effectively reduce the annealing temperature [1]. Such molecular effects due to cluster beam impact have been interested not only from the technological aspect but also from scientific one [2]. No complete explanation for this empirical fact has been made quantitatively. We can evaluate both the degree of crystallinity (= restoration) and the fraction of substitution (= activation) of implanted dopants based on crystallography [3]. Making use of mainly an empirical molecular dynamic simulation, we have shown the significance of cluster effect, in a way as how it effectively works on a damaged crystal to restore the crystallinity and promote the activation in the annealing process.

References

[1] M. Tanjyo et al.: Proc. ICCCICT, IEEE, Beijing, China (2004), p. 434.

[2] S. T. Nakagawa: J. Surf. Sci. Soc. Jpn., 52, 224-230 (2009).

[3] S. T. Nakagawa:“Ion beams in Nanoscience and Technology” ed. by R. Hellborg, Chap.9,