| 摘要 |
<p>A method for fabricating semiconductor devices having different characteristics on the same semiconductor substrate. First and second antimony introduction regions (24a, 27a) are created in a P-type semiconductor region (6) of a semiconductor substrate (41) so as to form first and second FET buried layers (8, 9). A mask (46) having first and second phosphorous introducing openings (47, 48) having different patterns is provided on the semiconductor substrate (41). Phosphorus is introduced into the semiconductor substrate (41) through the openings (47, 48). First and second phosphorus introduction regions (51, 52) are so formed as to overlap with the first and second antimony introduction regions (24a, 27a). The average impurity concentration of phosphorous of a first selection portion (49) for the first buried layer is higher than that of a second selection portion (50) for the second buried layer. An N-type epitaxial layer is formed over the P-type semiconductor region (6) including the antimony introduction regions (24a, 27a) and the phosphorous introduction regions (51, 52). Thus, the first and second buried layers are formed.</p> |
