| 摘要 |
PURPOSE:To form an impurity distribution having a desired profile at sidewalls of a groove with high accuracy by a method wherein, when an impurity is to be introduced into the sidewalls of the groove, ions are implanted while a semiconductor substrate where the groove capacitance is formed is tilted with reference to an ion beam and is turned. CONSTITUTION:Ions of boron are implanted by making use of a resist mask 5 as a mask. As a condition for ion implantation, a semiconductor substrate 1 is tilted by 10 deg. with reference to an ion beam and this semiconductor substrate 1 is turned mechanically at a speed of one revolution per second; first P-type impurity regions 9, 10 are thus formed. Furthermore, an angle of the semiconductor substrate with reference to the ion beam is changed to 30 deg.; the ions are implanted in the same manner while the substrate is turned; second P-type impurity regions 11, 12 are thus formed. The first P-type impurity regions are not implanted near the surface at the sidewalls of the groove due to a shadow by protruding parts 8 at the resist mask 5; the second P-type impurity regions where the ions are implanted with a tilt of a bigger angle are formed in these regions. |
