Stress Characterization of Selective Epitaxial Si_1-xGe_x Deposition for Embedded Source/Drain Before and After Millisecond Laser Anneal

Abstract

The purpose of this paper is to obtain a deep understanding of stress/bow behavior before and after millisecond laser anneal for epitaxially grown Si1­xGex layers. Stress measurements were performed by the laser reflectance method after different post-epi processing steps to further investigate the intrinsic film stress dependence on the ion implantation conditions (atom size, depth of the implant and dose) and the laser scan energy beam conditions (temperature, dwell time and power).

Growth and Processing Defects in CMOS Homo- and Hetero-Epitaxy

“…A high-dose ion implantation creates a significant amount of lattice damage and also strain relaxation in the SiGe layer (Fig. 5) (16), which need to be cured by a post-implantation anneal. The thermal budget of this anneal should be minimized in order to avoid excessive dopant diffusion, so that generally a high-temperature spike anneal is being used.…”

“…In order to reduce the thermal budget further, flash-lamp or laser annealing (socalled ms annealing -MSA) is becoming more and more popular (29,30). However, the high thermal stresses associated with the strong temperature gradients may result in strain relaxation of the SiGe layer when the laser annealing conditions (dwell time, maximum power) are not properly optimized (16,(31)(32)(33). This yields an increase in the junction leakage current (32,33), as illustrated in Fig.…”