Dynamics study of impact of ion acceleration in conventional ion implantation combined with plasma ion implantation

A novel technique was developed to improve the conventional ion implantation. In the newly-developed technique, a negative pulsed voltage, with respect to the vacuum chamber, was applied to the target so as to re-accelerate the impinging ions; and the conventional ion implantation was combined with plasma ion implantation. The various influencing factors, including the time evolutions of the field distribution above the negatively biased target surfaces, ion density distribution and ion trajectories, were modeled and simulated with 2-D software package particle-in-cell. The distributions of the implantation dosage, energy and incident angle of the ions at different times were statistically evaluated. The simulated results show that the negative bias significantly accelerates the ion for a second time, and the technique has a sold theoretical basis. Besides, the field distribution, originated from the bias, slightly bends the ion beam in such a way that its cylindrical shape changes into a bell-like one, considerably increasing the implantation area of the target. Moreover, the ion dosage decreased in radial direction because of the sheath configuration and ion deflection by the curved field. The advantages include relaxation of the power supply requirements and more flexibility of ion implantation.