Articles you may be interested inHigh resolution quantitative two-dimensional dopant mapping using energy-filtered secondary electron imaging Secondary electron ͑SE͒ imaging of semiconductors reveals contrast between n-and p-type areas that can serve as the basis for a two-dimensional dopant profiling technique. In this article, recent experiments that address sensitivity, spatial resolution, calibration methodology, p/n junction effects, and sample preparation issues are reviewed and discussed for boron doped silicon. In addition, several examples of successful applications of SE imaging as a two-dimensional dopant profiling technique are presented.
High-frequency capacitance-voltage (C C C-V V V ) measurements have been made on ultrathin oxide metal-oxide-semiconductor (MOS) capacitors. The sensitivity of extracted oxide thickness to series resistance and gate leakage is demonstrated. Guidelines are outlined for reliable and accurate estimation of oxide thickness from C C C-V V V measurements for oxides down to 1.4 nm.
Articles you may be interested inHigh resolution quantitative two-dimensional dopant mapping using energy-filtered secondary electron imaging Doping-dependent contrast in secondary electron images of p/n junctions in silicon obtained in a field-emission scanning electron microscope was observed and characterized. The optimum experimental conditions for observing this ''electronic'' contrast were established by investigating the effect of microscope and material parameters on the magnitude of the contrast. The contrast between the bright p-type areas and the darker n-type areas was maximized at an accelerating voltage of ϳ1 kV, and when a through-the-lens detector configuration was employed. Secondary electron contrast profiles of boron doped p ϩ /n junctions in silicon showed a good correlation with secondary ion mass spectroscopy depth profiles of the atomic concentration down to the 10 17 cm Ϫ3 level. However, similar results were not obtainable for n ϩ /p junctions. It is demonstrated that this contrast effect may be exploited for obtaining two-dimensional dopant profiles directly from secondary electron images of p ϩ /n junctions provided that the technique is empirically calibrated against a one-dimensional dopant profiling method.
(001) CZ silicon wafers were implanted with As+ at 100 keV to a dose of 1×1015/cm2 in order to produce a continuous amorphous layer to a depth of about 120 nm. Furthermore, the implant condition was such that the peak arsenic concentration was below the arsenic clustering threshold. Subsequently, a second As+ or Ge+ implant was performed at 30 keV to doses of 2×1015/cm2, 5×1015/cm2 and 1×1016/cm2, respectively, into the as-implanted samples. All of the samples were annealed at 800 °C for 1 h. The second implant was designed to be contained within the amorphous region created by the initial implant. The second As+ implant was also designed to provide the additional arsenic needed to exceed the critical concentration for clustering at the projected range. Of the three samples with the dual As+ implant the clustering threshold was exceeded for the two lower doses while the SiAs precipitation threshold was exceeded at the highest dose. In the case of the dual As+/Ge+ implants the clustering and precipitation thresholds were not reached. Since arsenic and germanium are similar in mass the extent of damage created by these implants would be comparable. The implanted and annealed specimens were analyzed using secondary ion mass spectroscopy and transmission electron microscopy. The difference in the defect evolution and the transient-enhanced diffusion of arsenic beyond the end-of-range region between the As+ and Ge+ implanted and annealed samples was used to isolate the effects of arsenic clustering and precipitation. The results showed that point defects induced during clustering and/or precipitation did not contribute to the enhanced diffusion of arsenic although these defects did coalesce to form extended defects at the projected range. However, damage beyond the end-of-range region did cause enhanced diffusion of arsenic.
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