CMOS and beyond

Lithography has played a key role in the scaling of CMOS-based integrated c ircuits. To fabricate sub-70 nm features, new techniques based on electron projection and extreme ultraviolet radiation are being developed. These and other lithographic solutions are discussed. For the ultimate in scaling, a n alternate approach would be to start with objects that are inherently nan o-scale in size, and use chemical techniques to have these objects self-ass emble into units that provide electronic functionality. Several classes of molecules, including carbon nanotubes, deoxyribonucleic acid (DNA) and cust om-synthesized organic molecules, are potentially suitable for this approac h. Some recent advances in their research will be reviewed. (C) 2000 Academ ie des sciences/Editions scientifiques et medicales Elsevier SAS.