Plasma Doping optimizing knock-on effect

Abstract

Many studies have been done to apply potential of Plasma Doping to manufacturing semiconductor devices. But some development problems about mass production are still left unsolved. One of the problems is that it is more difficult for Plasma Doping to control dosage. To clear this problem we investigated a dominant mechanism of mixing dopant atoms (boron) in silicon atoms, using inductively coupled plasma, radio frequency bias and B₂H₆ gas. And it is shown that main implantation mechanism of this plasma doping is the collision between B_xH_y* and biased Ar⁺: “knock-on phenomenon”. We presented new doping procedure “2STEP Process”, where B_xH_y* deposition coating and knocking-on the film by Ar⁺ accelerated with RF bias were completely separated. By using “2STEP Process”, it is shown that dosage can be controlled by deposition thickness and depth profile can be controlled by bias voltage.