The dependence of silicon selective epitaxial growth rates on masking oxide thickness

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Abstract
Growth rates in selective epitaxial depositions (SEG) and epitaxial lateral overgrowth (ELO) in the SiCl2H2-HCl-H2 system were studied as a function of masking oxide thickness. Enhanced growth was observed on wafers with thin (80 nm), as compared to thick (>300 nm), masking oxides. The higher growth rates on wafers with thin oxides were attributed to their higher surface temperature. The higher surface temperature for wafers with thin oxides is demonstrated to be due to decreased radiant heat transfer as compared to wafers with thicker oxides. The dependence of oxide thickness on growth rates was global, meaning that the bulk or large area field oxide thickness, and not the local oxide thickness in the immediate vicinity of the seed window, determined the growth rates. Hence, the dependence of growth rates on masking oxide thickness is critical in understanding, designing, and comparing experiments studying epitaxial deposition processes, but is less critical for technological applications of SEG and ELO.