Mechanics of Defects in Dislocation-Free Silicon Single Crystals

Abstract

The problems of defect mechanics in dislocation-free silicon single crystals are relevant and technically significant due to the intensive development of microelectronics, which imposes increasingly high demands on minimizing the level of micro- and nanodefects in silicon wafers used to manufacture microelectronic chips. The solution of these problems is associated with the study of the regularities of thermomechanical processes both at the stage of growing silicon single crystals and at subsequent thermal annealing of wafers cut from them. The article provides an overview of theoretical and experimental work aimed at developing ways to control these processes. This includes the development of physical concepts of defect formation in dislocation-free single-crystal silicon and the development of mathematical models corresponding to different temperature ranges, implemented both during the growth of a single crystal and during thermal annealing of wafers cut from it. Thus, near the crystallization temperature, the processes of fast recombination and diffusion transfer of intrinsic point defects (vacancies and interstitial silicon atoms) are simulated, while at lower temperatures, the processes of their agglomeration into microdefects (pores and clusters of interstitial silicon atoms) are simulated. The verification of such models is illustrated for two experimental processes of growing silicon single crystals with a diameter of 150 mm by the Czochralski method, as well as for the process of rapid high-temperature thermal annealing of silicon wafers cut on their basis.