Phosphorous (P + 1.0 MeV, 4.0 × 10 13 cm −2 ) and boron (B + 10 keV, 3.0 × 10 14 cm −2 ) implanted p − -Si(100) wafers were annealed with a wide range of annealing conditions (350-800 • C, 60-150 s) in a commercially available hot wall-based, rapid thermal annealing (RTA) system. Significant variations in sheet resistance were observed in different RTA conditions. Secondary ion mass spectroscopy (SIMS) P and B depth profiles did not show significant change. Room temperature photoluminescence (RTPL) spectra were measured from all wafers under two different excitation wavelengths (650 and 785 nm). RTPL spectra showed large variations in intensity and wavelength distribution corresponding to the sheet resistance. © The Author Conventional methods of noncontact monitoring for as-implanted Si are Therma-Probe and Rutherford backscattering spectroscopy (RBS). Secondary ion mass spectroscopy (SIMS) and transmission electron microscopy (TEM) are also used for dose, depth profile, and implant damage characterization. After electrical activation by thermal treatment of implanted Si, sheet resistance (Rs) measurements using four point probes are mainly used for monitoring implanted dopant activation. However, the four point probes require physical contact and relatively large area (typically one or more orders of magnitude wider than the probe spacing) of uniform quality (poor spatial resolution) for meaningful measurements. SIMS, RBS and TEM are also used as complementary crystal quality and defect verification techniques after implanted dopant activation.1-4 However, the conventional characterization techniques often overlook problems due to their insensitivity to surface passivation quality, residual implant damage and defects. 5Development of a noncontact, high spatial resolution implant activation monitoring technique is desired. Photoluminescence (PL) from Si is a good candidate for this application.Room temperature photoluminescence (RTPL) of crystalline Si, at wavelength ∼1.1 μm corresponding to interband transitions, is very sensitive to the density of non-radiative bulk and surface defects. 1,6 This can be used as an indication of defect concentration in Si. Monitoring of surface defect formation during oxidation processes and minor carrier diffusion length of epitaxial Si by RTPL intensity has been reported previously. 7,8 Promising results of spectroscopic RTPL studies on (ultra-) shallow implanted junctions and high energy low dose implanted junctions have also been reported previously.2,5,9-11 RTPL characterization of non-radiative defect density on surfaces and interfaces of Si with thin oxides have been studied.12-14 Metal contamination monitoring using spectroscopic RTPL has been reported previously.15 Plasma process induced damage (PPID) and plasma process chamber mismatch monitoring were also demonstrated using RTPL characterization of Si wafers. [16][17][18] In this paper, RTPL was investigated as a potential noncontact electrical activation monitoring technique for implant annealed Si wafers. The major...

Annealing process optimization was performed to achieve low resistivity CoSi 2 contacts used in different locations (word line, source, drain and gate regions) of advanced memory devices with various types of Si. The effect of Si type and annealing time on the resulting resistivity of the CoSi 2 was investigated over a wide range of annealing temperatures (350 ~ 900 o C) and times (60 ~ 300s) using a single wafer furnace-based (hot wall) rapid thermal annealing (RTA) system. The properties (conduction type, dopant, stacking structure and crystallinity) of the Si substrate contacting the Co film had a significant effect on the resulting CoSi 2 formation temperature and contact resistance. In general, the CoSi 2 formation temperature was reduced with the increase of RTA time. Significant differences in CoSi 2 formation temperature was observed from different types of Si. The CoSi 2 formation temperature for the source/drain (S/D) of P-type transistors was found to be the lowest. The CoSi 2 formation temperature for poly Si, used in cells, was found to be the highest and was the limiting factor in RTA temperature reduction efforts.

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