Ultrashallow Junctions Formed by Excimer Laser Annealing

Abstract
A very shallow p+n junction was formed by BF2 + ion implantation and excimer laser annealing (ELA) with single pulse irradiation. A thin amorphous layer formed by low-energy implantation was recrystallized effectively by single-pulse irradiation of an excimer laser. A shallow junction with little redistribution and sheet resistance as low as 100 Ω\Box was obtained. The junctions formed by ELA were compared with those formed by conventional rapid thermal annealing (RTA). It was confirmed that ELA with single-pulse irradiation can suppress unintentional diffusion of the implanted boron, and is more suitable for controlling the impurity profile of very shallow p+n junctions than RTA.