Showing papers by "Shuit-Tong Lee published in 1989"

Do oxygen molecules contribute to oxygen diffusion and thermal donor formation in silicon

Abstract: In- and out-diffusion experiments of oxygen in silicon indicate the existence of an oxygen-containing species diffusing much faster than interstitial oxygen at temperatures below about 700°C. The formation of oxygen-related thermal donors in the temperature range around 450°C also requires a fast diffusing species. The paper examines the possibility of this fast diffusing species beingmolecular oxygen, as had been suggested earlier. Special emphasis will be placed on experimental results which have become available since that time. These results allow one to relate thermal donor formation to the loss of interstitial oxygen and to oxygen precipitation. The role of carbon is also considered in this context.

Depth Profiles of Nitrogen and Chlorine in Pure Materials Through AMS of the Neutron Activation Products 14C and 36Cl

Abstract: Determination of the more common light elements such as nitrogen and chlorine at trace levels is difficult because of their high abundance on sample surfaces, in materials used to build analysis instruments, and in the residual gas of the instrument vacuum. We present here a new approach to analysis of these elements: accelerator mass spectrometry (AMS) combined with neutron activation. The problem of contamination is overcome by using neutron activation to produce long-lived radioisotopes which generally have low concentrations in the environment. For measurement of 14N and 35C1, AMS can provide sensitive background-free measurements of their neutron activation products 14C and 36C1 and, in addition, can provide depth profiles. These are the first results of this new method: depth profiles of nitrogen and chlorine implanted in semiconductor grade silicon.