A Quantitative Model for Silicon Yield Stress Calculations at Thin Film Edges

Abstract

The results are presented of a theoretical study on the yield stress of dislocation‐lean silicon. The obtained yield formula, which expresses the dependence of the external yield force on the intrinsic point defect concentration, is applied to the case of film edge induced dislocation generation in silicon substrates. A generally valid expression for the critical film thickness resulting in homogeneous defect nucleation is derived. The case of an inert anneal of dislocation‐lean, oxygen‐rich Czochralski silicon is studied more in detail. The theoretical results explain both the qualitative and the quantitative experimental results found in the literature.

Review—Device Assessment of Electrically Active Defects in High-Mobility Materials

“…The yield stress depends on the concentration of intrinsic point defects like interstitials and vacancies and is, therefore, impacted by the generation of extended defects. 52 A study of the nucleation of the different types of stressinduced dislocations is out of the scope of this review, which will be mainly concentrated on the electrical influence of the generated defects.…”

Carbon Enhancement of SiO[sub 2] Nucleation in Buried Oxide Synthesis Computer Simulations and Secondary Ion Mass Spectroscopy Depth Profiling

“…It may be created either by the emission of silicon interstitials into the matrix or by the accumulation of vacancies in the vicinity of the growing precipitate. Indeed, according to Vanhellemont and Claeys, 7,8 the critical radius (r c ) of the SiO 2 nucleus in ion beam damaged silicon may be described as follows…”

“…3 Moreover, this free volume leads to a decrease of r c of the SiO 2 nuclei. 3,7,8 On the other hand, C-O complexes are also assumed to be involved in the precipitation process. 3 Another stimulating factor which acts in our case is the formation of vacancy clusters during the evolution of the primary ion beam-induced vacancies.…”

“…2,3 These clusters, as well as Si-C, play an important role in releasing the volume misfit associated with the precipitate growth. 3,7,8 It is assumed that the small knee observed in Fig. 1, is due to the oxidation enhancement by vacancies and vacancy complexes during the diffusional redistribution of these defects between the external silicon surface and the main zone of oxidation reactions.…”

Jan Vanhellemont – 35 years of materials research in microelectronics

“…Another key achievement resulting from his doctoral research was the understanding of the impact of point defects (interstitials and vacancies) on the nucleation and the growth of both extended defects and precipitates. The density of self-interstitials, independent of their source, influences the critical radius of the oxygen precipitates, the shape of the precipitates and the silicon yield stress [7,8]. Indirectly, the point defects also influence the dislocation nucleation at film edges.…”