| 摘要 |
PURPOSE:In ion implantation, the start-up time and the shut-down time are adjusted in ion-acceleration voltage to control the distribution of the concentrations of the elements to be implanted near the surface of the substrate to a desired level. CONSTITUTION:When ions are implanted to wafers in a low-energy region, at least one selected from the start-up time and the shut-down time is varied in the voltage for ion acceleration. Thus, the concentrations of dopants are adjusted to the stopping range so that the amount of the elements to be implanted are varied freely. Consequently, the situation where the amounts of implanted elements on the surface of the substrate are too little after annealing is avoided. |
