Angle-resolved photoemission was used to study the surface electronic band structure of high quality single crystals of ferromagnetic CoS 2 (below 120 K). Strongly dispersing Co t 2g bands are identified along the 100 k direction, the¯ -X line of the surface Brillouin zone, in agreement with model calculations. The calculated surface band structure includes corrections for the previously determined surface structure of CoS 2 (001) and is in general agreement with the experimental photoemission spectra in the region of the Fermi level. There is evidence of the existence of several minority spin surface states, falling into a gap of the projected minority spin bulk CoS 2 (001) band structure.

We have investigated the intrinsic gettering (IG) of Cu in silicon wafers. Oxygen precipitates for IG were formed in wafers subjected to two-step annealing consisting of thermal treatment for 16 h at 800°C, then for 0-16 h at 1000°C. Cu was deposited on the back surface by dipping the wafers into a contaminant solution, and introduced into the wafer bulk from the back surface by heating for 5 min at 1000°C. The surface concentration of Cu was measured by total-reflection X-ray fluorescence. We found that the gettering efficiency, which was determined from the difference between the surface concentration on reference wafers and the corresponding concentration on the IG-treated wafers, depends on the Cu contamination concentration. Moreover, we used a simulation based on the Fokker-Planck equation to analyze the data with regard to the dependence of gettering efficiency on oxygen precipitate density. As a result, we have shown that the total number of oxygen precipitates, rather than their size determines the gettering efficiency. These experimental and calculated results can provide useful information for achieving effective IG of Cu. © 2002 The Electrochemical Society. All rights reserved.

Influence of backside Cu contamination during tack-end process on electrical cbaracteristics of MOSFETs was revealed.The influence is well explaiined in terms of Cu diffusion behavior at 40O0C, which strongly depends on SiO, thickness at h n t side and backside of wafa. Cu atoms brought in Si wafer can not diEw into the thick hnt-side SiO, film, but Cu atoms exist inside Si near SiO4Si interface after annealing. Accord~ng to this, backside Cu contamination during the back-end process does not affect T i m Zero Dielectric Breakdown (TZDB), Dit, or Vfb, but it decreases T i m Dependent Dielectric Breakdown (TDDB) lifetime and drastically enhances short-cbannel effect due to inpurify c a p t i o n .

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