Requirements for the quality of single-crystal silicon for microelectronics are permanently increased. This is directly associated with the increase in the packaging density of microelectronic elements arranged in the bulk of a silicon wafer. The problem of ensuring the uniformity of the electrophysical properties over the bulk of large-diameter silicon ingots forces one to treat the technology increasingly rigorously, optimize the technology parameters, and use the methods for quantitative numerical modeling of the growth process. At this stage, it is essential to know the accurate values of numerous properties of silicon and process materials over a wide range of parameters [1,2]. Specifically, with an increase in the silicon ingot diameter, the growth process is increasingly affected by the thermocapillary effect. This is of particular importance for silicon growth by crucibleless zone melting, where temperature gradients are large. Thus, an important role is played not only by the surface tension σ of liquid silicon, but also by its derivative k σ = ( d σ / dT ) with respect to temperature.Experimental investigation of all the properties of liquid silicon is rather complex and imposes high requirements on equipment. First, the melting point of silicon is high ( T m ≈ 1685 K [3]). Second, silicon melt and vapor are corrosive [3]. When investigating the surface tension, it is very important to take into account that many impurities can be surface-active. These impurities can arrive at the surface from the protective atmosphere of equipment, evaporate from equipment materials at high temperatures, dissolve at the meltcrucible contact, etc. Of importance are also the high initial purity of silicon under investigation and the measurement technique.Many methods for measuring σ ( T ) require the preliminary knowledge or special measurement of other properties of silicon at the measurement temperature. Most often, it is necessary to know density ρ (or ρ in these methods is determined less accurately than in others), for example, in the sessile drop method [4] and its variants-the large drop method [5], the ring method [6], the dynamic pendant drop method [7], the dropweight method [4, 5], and the method of surface laserlight scattering [8] (which uses the phenomenon of capillary waves-ripplons [4]). Note one of the recent most complete investigations of silicon density in [9].σ( Τ ) of liquid silicon has been experimentally studied for already a half of century. Almost all the experimenters compared their values with the results of previous investigations. Unfortunately, almost every author supposed that his data were the most accurate. As a result, an unprejudiced analysis has never been performed. Today, the spread of the data at T m is from 0.7 to 0.88 J/m 2 for σ and from -0.01 × 10 -3 to -0.67 × 10 − 3 J/(m 2 K) for k σ . Previously, such a spread was to a certain extent good enough for engineers to qualitatively estimate the growth phenomena. At present, for quantitative modeling, such a spread of the experimen...
