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Characterization of Si wafers by delineation of crystal originated particles (COP) provides insight into size and radial distribution of crystal related defects. A good correlation of the COP densities with gate oxide integrity and flow pattern defect densities is observed. The density and size distribution of COP in Czochralski Si ingots can be modified by the pulling rate and the cooling conditions of the crystal and is further influenced by high doping concentrations. The COP densities are comparable on wafers with (100) Si and (111) Si orientation as well as on p-and n-type wafers with moderate doping level. No COP are found on float zone (FZ) and on epitaxially grown wafers. Crystal defects are also delineated by chemomechanical polishing and can be detected on the wafer surface as light point defects (LPD). LPD densities, however, do not necessarily correlate with the corresponding COP densities after SC1 treatment and do not reflect the quality of the crystals because polishing delineates only part of the larger crystal defects to a size which is above the detection limits of commercially available scanning surface inspection systems. High temperature annealing results in reduction of defect sizes and partial dissolution of COP. Investigations of FZ and oxygen doped float zone indicate that oxygen is participating in the formation of COP.

We present measurements of the electrical resistivity ρ(T ) on high-quality single-crystalline CeNiSn under both hydrostatic pressure up to 1 GPa and uniaxial pressure up to 0.25 GPa. At ambient pressure, ρ(T ) along the orthorhombic a-axis (b-axis) shows two maxima at T L = 12 K (14 K) and T H = 74 K (40 K), respectively, which arise from the Kondo scattering of conduction electrons by the crystal-field ground state and excited states. With increasing hydrostatic pressure, both T L and T H increase linearly, and for P 0.8 GPa, the anisotropy in ρ(T ) for I a and I b almost vanishes as a result of increased hybridization between the 4f electrons and the conduction electrons. Under P a, both T L and T H in ρ(I b) increase similarly to under hydrostatic pressure. Under P c, however, the depression of T L in ρ(I a) and ρ (I b) suggests that the c-f hybridization in the crystal-field ground state is weakened in the a-b plane of CeNiSn.

The impact of nanotopography of silicon wafers on the thickness homogeneity of oxide layers after deposition and chemical mechanical polishing (CMP) is investigated. Comparison of nanotopographical height with post-CMP oxide thickness for the same position on a wafer may result in inconclusive data with no obvious correlation. However, a simple relation is obtained when (i) the root-mean-square (rms) roughness of nanotopographical height false(σNHfalse), (ii) the standard deviation of post-CMP oxide thickness false(σOTDfalse), and (iii) the standard deviation of post-CMP oxide thickness caused only by fluctuations of the combination of oxide deposition and CMP false(σCMPfalse) are considered: σOTD2≈σCMP2+αfalse(λP)2σNH2. α false(λPfalse) is a coefficient that is fairly independent of the nanotopography features of wafers as well as the area for which the rms roughness and the standard deviations are determined, but which depends on the planarization length λP of the CMP process applied. Regarding the CMP process used in the present investigation, α is found to be about −0.15±0.05, indicating that only 15% of the nanotopographical height values of as-polished wafers transfer into post-CMP oxide thickness variations. A negative α implies that nanotopographical surface depressions are related to enhanced post-CMP oxide thickness and vice versa. © 2002 The Electrochemical Society. All rights reserved.