| 摘要 |
PURPOSE:To make the distribution of the concentration of an electrically active impurity adhered on the side wall of a minute hole along the side wall the desired distribution of the concentration by changing the accelerating voltage of an irradiated ion beam. CONSTITUTION:After boron fluoride 40 is deposited on the surface of a region where the trench of a boron implanted region 3 and a p-type silicon substrate 1 is formed, if a silicon ion beam 5 accelerated by 150KV is irradiated on the boron fluoride 40, part of the boron implanted region 3 and part of the p-type silicon substrate 1 are etched by the irradiation of the silicon ion beam 5 and a trench 60 is formed in the substrate 1 and the boron implanted region 3. Then, a trench 61 is formed by etching the substrate 1 by raising the accelerating voltage of the silicon ion beam 5 to 200KV. In this case, the range of a sputtered boron atom is increased due to greater accelerating voltage and the quantity of boron adhered to the side wall of the trench 61 near the bottom is reduced. This can change the concentration of an electrically active impurity adhered to the side wall of a minute hole along the side wall of the minute hole. |
