Substrate defects affecting gate oxide integrity

Autor: Manabu Itsumi
Rok vydání: 2000
Předmět:
Zdroj: Materials Science and Engineering: B. 73:184-190
ISSN: 0921-5107
DOI: 10.1016/s0921-5107(99)00458-4
Popis: During the past 20 years, there have been several breakthroughs regarding the research on grown-in defects in Czochralski silicon (CZ-Si) for commercial use. The presence of oxide defects originating in CZ-Si was first reported in 1979, and it was soon proposed that they could be eliminated by sacrificial oxidation, as well as by nitrogen annealing or hydrogen annealing. In 1990, crystal-originated particles were reported, but the origin of the defects remained unclear. Octahedral void defects were found under oxide defects in 1995, and in 1996, octahedral void defects were also found in bulk CZ-Si. A series of these discoveries lead some manufacturers of Si metal-oxide-semiconductor large-scale integrated circuits to widely recognize that the octahedral void defects are closely related to the failures of the actual dynamic random access memories they manufactured. The principal factor for the generation of gate-oxide defects may be oxide thinning at the corners and/or edges of the voids (as a geometrical effect). Another factor may be due to some impurities in the voids reducing the dielectric strength of gate oxides, even though the presence of impurities that may have accumulated in the void has not been directly observed. However, we have found two kinds of thin marks located around the void defects after oxidation, and we assume that the marks are closely related to the impurities originating in the void defects.
Databáze: OpenAIRE
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