SENSITIVITY ANALYSIS OF ION-IMPLANTED SILICON-WAFERS AFTER RAPID THERMAL ANNEALING

In this study, we have investigated sensitivities of the ion implanted silicon wafers processed by rapid thermal annealing (RTA), which can reveal the variation of sheet resistance as a function of annealing te mperature as well as implantation parameters. All the wafers were sequ entially implanted by the arsenic or phosphorous implantations at 40, 80, and 100 keV with the dose level of 10(14) to 2 x 10(16) ions/cm(2) . Rapid thermal annealing was carried out for 10 s by the infrared irr adiation at a temperature between 850 and 1150 degrees C in the nitrog en ambient. The activated wafer was characterized by the measurements of the sheet resistance and its uniformity mapping. The values of sens itivities are determined from the curve fitting of the experimental da ta to the fitting equation of col relation between the sheet resistanc e and process variables. From the sensitivity values and the deviation of sheet resistance, the optimum process conditions minimizing the ef fects of straggle in process parameters are obtained. As a result, a s trong dependence of the sensitivity on the process variables, especial ly annealing temperatures and dose levels is also found. From the sens itivity analysis of the 10 s RTA process, the optimum values for the i mplant dose and annealing temperature are found to be in the range of 10(15) ions/cm(2) and 1050-1100 degrees C, respectively. The sensitivi ty analysis of sheet resistance will provide valuable data for accurat e activation process, offering a guideline for dose monitoring and cal ibration of ion implantation process.