Long pulse laser thermal processing: annealing duration trade-off for next generation semiconductor hot processes

Abstract

Not only laser annealing is an alternative to classical furnace thermal processes, but today laser thermal processing (LTP) appears very suitable for various processes of various materials of the semiconductor industry. The duration of the laser pulse heating the material to be annealed needs to be short enough to induce both nm-scale localized and metastable thermodynamic cycles (ns to mus range) but long enough to avoid too high degree of superheating regime responsible for damage or cancellation of the annealing process. We gather in this paper the main results found in both theoretical and experimental literature comparing the effect of the heating pulse duration on the effectiveness of the annealing. Simulation calculations highlight the added value brought by the relatively long thermal cycle induced by a long-duration laser pulse in either defects curing or activation of electrical dopants. Electrical properties measured on real device structures from ultra-shallow junction annealed by a long pulse-LTP confirm the potential of a 200 ns-duration excimer laser irradiation for dopant activation in sub-45 nm CMOS manufacturing