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Impact of heavy doping with donors on CZ silicon properties
Author(s) -
Porrini M.,
Duchini J.,
Bazzali A.
Publication year - 2014
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201300392
Subject(s) - wafer , antimony , dopant , doping , materials science , silicon , analytical chemistry (journal) , void (composites) , arsenic , limiting oxygen concentration , oxygen , mineralogy , chemistry , nanotechnology , composite material , optoelectronics , metallurgy , chromatography , organic chemistry
This work reports a detailed characterization of 200 mm silicon wafers heavily doped with antimony, arsenic or phosphorus, in the range 1–50 mΩ•cm, corresponding to 7 × 10 19 – 2 × 10 17 at·cm −3 . Grown‐in voids (revealed as light‐scattering objects on the wafer surface) are shown to be controlled by the dopant concentration. For As‐doped wafers the voids show a pronounced increase in their density up to [As] = 1.7 × 10 19 cm −3 , but at higher concentration the void density drops sharply. The same behaviour was found for P‐doped wafers where a sharp drop occurs at [P] > 2.9 × 10 19 cm −3 . In the case of antimony, the explored concentration range was sufficient only to reveal the increasing side of the curve. AFM characterization confirmed the morphology of voids as also seen in lightly‐doped silicon. Both single and double voids were observed. The oxygen precipitate density (BMD) was measured after submitting the wafers to a stabilization and growth thermal cycle. Overall it ranges from 1 × 10 6 ( = detection limit) to 1.5 × 10 10 counts/cm 3 . The relationship between BMD density and oxygen concentration follows the classical S‐shaped curve, indicating that also for heavily doped N+ type wafers the oxygen content plays a major role on BMD formation.