Silicon wafers were preamorphized with 70 keV Si+ at a dose of 1×1015 atoms/cm2, generating a deep amorphous layer of 1800 Å. Implants of 500 eV B+11, with and without 6 keV F+, followed at doses of 1×1015 atoms/cm2 and 2×1015 atoms/cm2, respectively. After annealing at 550 °C, secondary ion mass spectroscopy determined that the diffusivity of boron in amorphous silicon is significantly enhanced in the presence of fluorine. Ellipsometry and cross-sectional transmission electron microscopy indicate the enhanced diffusion only occurs in the amorphous layer. Fluorine increases the boron diffusivity by approximately five orders of magnitude at 550 °C. It is proposed that the ability of fluorine to reduce the dangling bond concentration in amorphous silicon may reduce the formation energy for mobile boron, enhancing its diffusivity.

The effect of laser thermal processing ͑LTP͒ on implantation-induced defect evolution and transient enhanced diffusion ͑TED͒ of boron was investigated. A 270-Å-thick amorphous layer formed by 10 keV Si ϩ implantation was melted and regrown using a 20 ns ultraviolet laser pulse. Transmission electron microscopy revealed that recrystallization of the amorphous layer following LTP results in a high concentration of stacking faults and microtwins in the regrown region. Also, the end-of-range loop evolution during subsequent 750°C furnace annealing, is different in a LTP sample compared to a control sample. Secondary ion mass spectroscopy of a boron marker layer 6000 Å below the surface showed that LTP alone produced no enhanced diffusion. However, during subsequent furnace annealing, the boron layer in the LTP sample experienced just as much TED as in the control sample which was only implanted and furnace annealed. These results imply that laser melting and recrystallization of an implantation-induced amorphous layer does not measurably reduce the excess interstitials released from the end-of-range implant damage. © 1999 American Institute of Physics. ͓S0003-6951͑99͒00149-7͔Continued scaling of the transistor to sub-100 nm dimensions requires the formation of ultrashallow highly doped abrupt junctions for contact formation. A box-shaped, high dopant concentration profile could ideally meet such a requirement. 1 Ion implantation and conventional rapid thermal annealing inevitably lead to less than ideal Gaussian or exponential dopant profile. Also, the interaction between implantation induced point defects and dopant atoms during annealing can considerably broaden the profile shape through transient enhanced diffusion ͑TED͒. One proposed method for circumventing some of these problems is the use of laser annealing. 2 Various approaches proposed include: melting and regrowing crystalline silicon in the presence of a dopant ͑the PGILD process͒ or preamorphization of the surface by implantation followed by a dopant implant into the amorphous material and finally laser melting only the amorphous material ͓also called laser thermal processing ͑LTP͔͒. 2-4 The advantage of the second method is that lower temperatures can be used because amorphous Si melts at a temperature 300°C lower than crystalline Si. This is important because it allows thickness of the melted region to be controlled by the preamorphization.One question that remains is does LTP have an advantage in the transient enhanced diffusion reduced from the implant. It is well known that after implantation induced amorphization of Si, there exists a highly damaged region in the crystalline material just beyond the amorphous/ crystalline interface. 5 This layer, referred to as the end-ofrange ͑EOR͒ damage region, is known to contain a large supersaturation of interstitials. During annealing these interstitials are released and flow both toward the surface and into the bulk, resulting in TED of the common dopants ͑e.g., B, As, P͒. 6 This TED has the undesirable effe...

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The reasons underlying correlations and lack of corrrelations between SPIDER-MEM and CHARM-2 results are investigated for wafers inplanted in a high-current, low enzrgy ion implai;ter equipped with a plasma charge-control system, The results can be explained by taking into account the device structure and physics of the SPIDER-MEM devices, and the charging characteristics of the implanter. The work has important implications for comparisons of results obtained from charging monitors and damage monitors.