Alternating Reversed Scanning Sequence for Improved Within-Wafer Uniformity During Nonmelt Laser Annealing of Arsenic-Implanted Silicon

Beyond the 45-nm technology node, nonmelt laser thermal annealing (LTA) is a potential candidate to replace the spike rapid thermal annealing (RTA) for the formation of ultrashallow and highly activated source/drain extension junctions. However, one major drawback of LTA is that it is ineffective in...

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Bibliographic Details
Published in:IEEE transactions on semiconductor manufacturing 2010-05, Vol.23 (2), p.340-343
Main Authors: Chyiu Hyia Poon, See, Alex, Mei Sheng Zhou
Format: Article
Language:English
Subjects:
Annealing
Applied sciences
Budgeting
Budgets
Compound structure devices
Deactivation
Electronics
Exact sciences and technology
Heating
Ion implantation
laser annealing
Laser beams
Lasers
Microelectronic fabrication (materials and surfaces technology)
Optical pulses
p-n junctions
Power lasers
Rapid thermal annealing
resistance
Scanning
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Semiconductor lasers
semiconductor materials
Semiconductors
Silicon
Temperature
Thermal degradation
Thermal resistance
Variability
Wafers
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Summary:Beyond the 45-nm technology node, nonmelt laser thermal annealing (LTA) is a potential candidate to replace the spike rapid thermal annealing (RTA) for the formation of ultrashallow and highly activated source/drain extension junctions. However, one major drawback of LTA is that it is ineffective in the removal of implantation-induced damage. As such, arsenic deactivation, as a result of cluster formation due to the release of excess interstitials from the end-of-range (EOR) region, is observed when a post-LTA thermal budget is applied. Since conventional LTA comprises localized heating using a laser beam scanning the wafer front-side in a nonalternating sequence, different portions of the wafer will experience varying post-LTA thermal budget from the hotplate, depending on when the laser beam scans through it. Because dopant deactivation increases as the post-LTA thermal budget increases, severe degradation of the within-wafer uniformity is observed. To address this problem, a multiple-pulse, alternating reversed laser scanning technique is implemented to average out the differences in post-LTA thermal budget across the wafer between each pulse. Using such a scheme, the variations in subsequent dopant deactivation across the wafer is reduced and significant uniformity improvement of up to 50% is observed.
ISSN:0894-6507
1558-2345
DOI:10.1109/TSM.2010.2045589