Boron diffusion through thin gate oxides: Influence of nitridation and effect on the Si/SiO2 interface electrical characteristics

Abstract

The diffusion of boron in N2 ambient is studied by using p+ polysilicon metal-oxide-silicon structures annealed during times long enough to allow boron diffusion through the gate oxide, up to the underlying substrate. Assuming equilibrium segregation at the interfaces, the boron diffusivity in the oxide is calculated by numerically fitting the resulting profile in the substrate. It is found that B diffuses in SiO2 with an activation energy of about 3 eV. We also quantify the influence of the nitridation of the oxide, and confirm its efficiency as a diffusion barrier. However, this study reveals a strong inconsistency between the extracted diffusivity values of B in SiO2 and the amount of B atoms being able to reach the Si/SiO2 interface to account for the observed interface state density.

Silicide Formation of Atomic Layer Deposition Co Using Ti and Ru Capping Layer

“…Meanwhile, epitaxial CoSi 2 was grown by annealing PE-ALD Co with the SiO x N y interlayer, 6) because SiO x N y formed during PE-ALD Co process using NH 3 plasma is stronger in diffusion barrier properties than SiO x . 16,17) Therefore, the multiple peaks and comparable silicide formation temperature to sputtered Co indicates that the silicide formation of Th-ALD Co is similar to sputtered Co.…”

Additional fluorine passivation to pyrolytic-N2O passivated ultrathin silicon oxide/Si(100) films

“…For the INAA of the F content in the silicon oxide films, 56-58 the main analytical conditions were thermal neutron flux of about 1.7ϫ 10 17 n /m 2 s, irradiation time of 5 s, time after irradiation to measurement of 15 s, and ␥-ray detection energy of 1633.602 keV induced by the ␤ + radioactive decay of the nuclear reaction of 19 F͑n , ␥͒ 20 F. To eliminate the influence of other nuclear reactions ͑i.e., interfering nuclear reactions͒, especially 27 Al͑n , ␥͒ 28 Al, the Al content of the sample was made less than about 10 ppm. Carrying this procedure through, F content can be determined at the lower limit of about 1.9ϫ 10 12 at./ cm 2 number density, which is derived from the typical ox of PGP-oxidized films, about 2.40 Mg/ m 3 .…”

“…10,11,13 This suggests that, in addition reducing the H-related bonds by ultradry oxidation, PGP changes parts of the residual H-related single bonds, such as Si-H and/or Si-OH, into stronger N-related double and/or triple bonds, such as Si-N v O 2 and/or Si 3 w N. It may be improbable that the triple bonds can be formed at such a modest concentration of N. However, the excess Si atoms relative to the stoichiometric SiO 2 composition exist near the PGP-grown silicon oxide/Si interface 12,22 and the triple bonds have been confirmed at the oxynitride/Si interface due to the Si atomic density mismatch and the reduction of the mismatch-induced strain, 23 so the possibility of the triple bond formation has been listed here. In PGP, the apparent nitride ͑e.g., SiO x N y ͒ inclusions and/or layers obtained by general oxynitridation methods [24][25][26][27][28][29] are not intentionally produced. That is, instead of H passivation of all silicon dangling bonds in the oxide films and near their interfaces, N passivation against parts of the residual H-related single bonds aggressively proceeds in situ by the thermally activated NO 2 and N 2 generated from the pyrolytic N 2 O.…”

Excess Si atoms near the pyrolytic-gas-passivated ultrathin silicon oxide/Si(100) interface

“…1. 8,9 This suggests that, in addition to a reduction of the H-related bonds by ultra-dry oxidation, PGP changes parts of the residual H-related single bonds, such as Si-H or Si-OH, into stronger Nrelated double or triple bonds, such as Si-N ϭ O 2 or Si 3 ≡ N. The apparent nitride (e.g., SiO x N y ) inclusions or layers obtained by general oxynitridation methods [17][18][19][20][21][22] are not intentionally produced. That is, instead of H passivation of silicon dangling bonds in the oxide films and near their interfaces, N passivation is aggressively performed in situ by the thermally activated NO 2 and N 2 generated from the pyrolytic N 2 O.…”