DRY ETCHING METHOD OF SILICON THIN FILM AND THIN FILM TRANSISTOR

摘要

PURPOSE:To selectively etch away silicon thin film in excellent controllability and evenness using an etching gas free from the Freon regulation. CONSTITUTION:An etching gas containing hydrogen chloride gas and Freon 14 gas is used, for dry etching step in order to form a source region 5 and a drain region 6 by separating a silicon layer with activating energy not exceeding 0.2eV on an i-silicon layer 7. Since the hydrogen chloride gas and Freon 14 gas are free from the Freon regulation, the mixed gas of these gasses can be used for selective dry-etching step of n<+> silicon layer and i-silicon layer in excellent controllability and evenness.