| 摘要 |
PURPOSE: A method for forming a selective epitaxial layer is to previously remove oxide on a wafer substrate by flowing a washing gas under a certain condition, without providing a selective epitaxial growth(SEG) cleaning apparatus with an additional provision. CONSTITUTION: Before an SEG process is carried out, a lower structure of a substrate is cleaned in-situ using NF3 or SF6 gas. At that time, a pressure of the NF3 or SF6 gas belongs to a range from 0.001 to 760 torr, and the cleaning process is carried out under a condition that a temperature is within 500 to 1200 deg.C. Upon cleaning the lower structure, any one of inert gas consisting of N2, Ar and He is mixed with the NF3 or SF6 gas at a mixing ratio of 1 : 1 to 100. If the lower structure is cleaned using the NF3 or SF6 gas, an etching reaction regarding to silicon oxide is highly produced relative to silicon.
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