Ultra-shallow, box-like impurity profiles are produced using Gas Immersion Laser Doping (GILD) and then analyzed by spreading resistance profilometry (SRP) and secondary ion mass spectrometry (SIMS) to determine the impurity distribution. At high concentrations, the profiles obtained by SRP exhibit the expected box-like shape over the entire range of junction depths: The measured concentration within the junction region is uniform while the dopant gradient at the junction exceeds 0.5 decades/nm. In comparison, the same profiles analyzed by SIMS show a broader transition at the metallurgical junction. Caused by knock-ons and ion mixing during the sputtering process, this inaccuracy is reduced, but not eliminated by lowering the acceleration energy of the primary Cs{sup +} ion beam. At lower concentrations (< 10{sup 19}/cm{sup 3}), profiles analyzed by SRP exhibit shallower junctions than expected. Electrical measurements of diodes and Hall structures show that high-quality, ultra-shallow n{sup +}p, np and pn are fabricated with good dose control using GILD. For complete characterization of GILD, accurate measurement of both chemical and electrically-active dopant profiles are required. At present, neither SIMS nor SRP provides an entirely accurate impurity profile.

The Geotechnical Board, a part of the US National Research Council, which is the operating arm of the National Academy of Sciences and the National Academy of Engineering, serves to advise the federal government and others on issues where geotechnology can have an impact, such as environmental remediation and infrastructure development. The board met three times during the reporting period to review current projects and to initiate activities that move the knowledge base of geotechnology forward. The board operates with two long-standing national committees, the US National Committee for Rock Mechanics and the US National Committee on Tunneling Technology. It also conducts special studies at the request of the government. A list of attachments is given.