Monitoring of Rapid Thermal Processing at Temperatures lower than 1050°C with p-Type Silicon Wafer
Original Publication Date: 2004-May-25
Included in the Prior Art Database: 2004-May-25
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Implanted silicon monitor wafers are used for monitoring the rapid thermal processing for implanting dopants. They are annealed in a rapid thermal processing tool, and then their sheet resistance is measured. The sensitivity value of the rapid thermal process determines the valuation of the sheet resistance. Up to now monitoring the process at temperatures lower than 1050°C is done with n-type silicon monitor wafers which are doped with boron with a dose of 3*1015 cm-2 and an energy of 25 keV. The disadvantage of n-type wafers is that they are relatively expensive. There is currently no possibility of using cheaper p-type wafers instead. It is therefore proposed to employ a phosphorus implanted p-type silicon monitor wafer with a dose of 1*1014 cm-2 to 1*1015 cm-2 and an energy of 7 keV to 30 keV. Additionally there has to be a cleaning procedure before and after the implantation of the phosphorus, and a specified time limit between the precleaning procedure and the implantation. Monitoring is then accomplished through the activation of phosphorus in pure oxygen or gas mixtures with oxygen. This approach makes monitoring of rapid thermal processes with p-type monitor wafers at temperatures lower than 1050°C possible and hence offers reduction of costs.