Numerical investigation of carbon and silicon carbide contamination during the melting process of the Czochralski silicon crystal growth

Abstract

Carbon contamination in single crystalline silicon is detrimental to the minority carrier lifetime, one of the critical parameters for electronic wafers. In order to study the generation and accumulation of carbon contamination, transient global modeling of heat and mass transport was performed for the melting process of the Czochralski silicon crystal growth. Carbon contamination, caused by the presence of carbon monoxide in argon gas and silicon carbide in the silicon feedstock, was predicted by the fully coupled chemical model; the model included six reactions taking place in the chamber. A simplified model for silicon carbide generation by the reaction between carbon monoxide and solid silicon was proposed using the closest packing assumption for the blocky silicon feedstock. The accumulation of carbon in the melted silicon feedstock during the melting and stabilization stages was predicted. Owing to this initial carbon content in the melt, controlling carbon contamination before the growth stage becomes crucial for reducing the carbon incorporation in a growing crystal.

Oxygen and Nitrogen Transfer in Furnaces in Crystal Growth of Silicon by Czochralski and Directional Solidification Processes

“…They reported the results by suing a quasi-static meth calculation. Such a method cannot take into account C accumulation during CZ-Si c growth [6], then the quasi-static assumption is not able to predict the C content in Si Then, the transient method of heat and mass transport is necessary to study C cond tion quantitatively during the melting process of CZ-Si crystal growth [15].…”

Effect of the packing structure of silicon chunks on the melting process and carbon reduction in Czochralski silicon crystal growth

“…Reactions ( 4)-( 6) are involved at the gas/Si interface and in the unmelted Si feedstock. To investigate the surface reaction and deposition, a simplified model for SiC generation by the reaction between CO and Si was used for the surface of the packed Si chunks 17) . O, C, SiO, CO, and SiC coexist in the unmelted Si feedstock and at the gas/Si interface.…”

“…Transport phenomena of C as well as relevant impurities and species in the CZ-Si process have been extensively studied in the last few decades [9][10][11][12][13][14][15][16][17] . It has been found that back diffusion of the generated CO is the main origin of C contamination in Si feedstock.…”

“…However, the C content predicted under the quasi-static assumption does not account for C accumulation during CZ-Si crystal growth 11) . Transient global simulations of heat and mass transport have been performed for C accumulation in the melting process of CZ-Si crystal growth 16,17) . However, in these studies, packed Si chunks were modeled with the thermal conductivity of bulk Si.…”

Development of carbon transport and modeling in Czochralski silicon crystal growth

“…Liu et al. recently addressed the generation, transport, and accumulation of C during the melting process in a CZ‐Si furnace. The accumulation of C in the melt was investigated according to the transient feature of the CZ‐Si process.…”