15.1 Introduction

The history of ion implantation in semiconductors stretches back some 50 years. The first published report of the bombardment of semiconductor surfaces to change electrical properties appears to be that of Ohl at Bell Laboratories in 1952 (Ohl 1952). Shockley, at the same institution in 1954, filed a remarkably prophetic patent in which he detailed the doping possibilities of implanting donor or acceptor impurities to control the electrical properties (Shockley 1954). This patent basically describes the art as it is practiced today, including the annealing to remove damage and diffuse the dopant. There was much worldwide research in the 1960s investigating the implantation phenomenon, but the technique was not widely accepted into production until the 1970s. It was then that the value of implantation for threshold voltage adjustment and highly doped, self-aligned structures contributed significantly to the integrated circuit (IC) revolution.

The sophistication of implant machines and the devices they produce have evolved continuously over the past 50 years, and this chapter will give a flavor of the state-of-the-art of the technology and current challenges. At the same time, the economic challenges or drivers cannot be overemphasized. Economics have been an important factor in ion implantation from its inception in chip manufacturing because the implanter cost was incremental to the diffusion systems with which implant competed (McKenna 2000; Rose 1985).

Silicon technology drives...