SHALLOW JUNCTION DOPING TECHNOLOGIES FOR ULSI

The fabrication of thin, sub-40 nm doped layers in Si with high concen trations of electrically active dopants and box-like profiles is a maj or technological challenge. Making these regions without introducing r esidual defects in the material and without affecting the properties o f other material regions in the device is even more difficult. The nee d to control these properties of doping profiles in ultra-large-scale integrated (ULSI) circuits has driven the study of low energy implanta tion, transient enhanced diffusion (TED), and focused the search for n ew shallow junction doping techniques. In this article, we review the motivation for shallow junctions, specific requirements for shallow ju nctions used in deep sub-micron dimension metal-oxide-semiconductor fi eld effect transistors (MOSFETs), current understanding of implant and diffusion processes, and the state-of-the-art in low energy implantat ion and a number of alternate doping technologies, including plasma im plantation, gas-immersion laser (GILD) doping, rapid vapor-phase dopin g (RVD), ion shower doping, and decaborane (B10H14) implantation. (C) 1998 Elsevier Science S.A. All rights reserved.