Depth profiles of oxygen precipitates in nitride-coated silicon wafers subjected to rapid thermal annealing

ABSTRACTEffects of defect evolution during rapid thermal annealing (RTA) on the anomalous diffusion of ion implanted boron have been studied by implanting silicon ions prior to boron implantation with doses ranging from 1 × 1014cm−2 to 1 × 1016cm−2 at energies ranging from 20 to 150 KeV into silicon wafers. Diffusion of boron atoms implanted into a Si preamorphized layer during RTA is found to be anomalous in nature, and the magnitude of boron displacement depends on the RTA temperature. While RTA of preamorphized samples at 1150°C shows an enhanced boron displacement compared to that in crystalline samples, a reduced displacement is observed in preamorphized samples annealed by RTA at 1000°C. In addition, low dose pre-silicon implantation enhances the anomalous displacement significantly, especially at high RTA temperatures (1 150°C). Finally, the anomalous diffusion is found to depend strongly on the defect evolution during RTA.

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Vacancy Species Produced by Rapid Thermal Annealing of Silicon Wafers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.242.135 ◽

2015 ◽

Vol 242 ◽

pp. 135-140 ◽

Cited By ~ 2

Author(s):

Vladimir V. Voronkov ◽

Robert Falster

Keyword(s):

Thermal Annealing ◽

Rapid Thermal Annealing ◽

Silicon Wafers ◽

Density Profiles ◽

Cooling Stage ◽

Czochralski Silicon ◽

Self Diffusion ◽

Oxygen Precipitation ◽

Oxide Precipitate ◽

Precipitate Density

Rapid thermal annealing (RTA) of Czochralski silicon wafers at around 1260°C installs a depth profile of some vacancy species. Subsequent oxygen precipitation in such wafers is vacancy-assisted. The data on RTA-installed vacancy profiles - and the corresponding precipitate density profiles - suggest that there is a slow-diffusing vacancy species (Vs) along with two fast-diffusing species: a Watkins vacancy (Vw) manifested in irradiation experiments and fast vacancy (Vf) responsible for the high-T vacancy contribution into self-diffusion. The Vs species are lost during cooling stage of RTA, and the loss seems to occur by conversion of Vs into Vf followed by a quick out-diffusion of Vf. A model based on this scenario provides a good fit to the reported profiles of oxide precipitate density in RTA wafers for different values of TRTA and different cooling rates.

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Thermal Donor Removal by Rapid Thermal Annealing: Infrared Absorption

MRS Proceedings ◽

10.1557/proc-46-269 ◽

1985 ◽

Vol 46 ◽

Cited By ~ 3

Author(s):

Herman J. Stein ◽

S. K. Hahn ◽

S. C. Shatas

Keyword(s):

Excited State ◽

High Temperature ◽

Excited States ◽

Thermal Annealing ◽

Rapid Thermal Annealing ◽

Infrared Absorption ◽

Excited State Absorption ◽

Thermal Donor ◽

Oxygen Cluster ◽

Oxygen Precipitates

AbstractRapid thermal annealing of thermal donors in Si with 10 sec anneal times at temperatures between 600 and 1000 °C has been investigated by infrared absorption at 80 K. Thermal donors A through D, which are identified by excited state absorption, are present in as-grown Czochralski Si; whereas excited states for donors A through F as well as photoionization of thermal donors are observed after extended heating at 450 °C. The temperature required for rapid thermal annealing is lower when only donors A through D are present. Removal of thermal donors A through F by rapid thermal annealing at temperatures > 800°C restores 7 to 8 oxygen atoms to interstitial sites per electricallӯ measured donor removed. This ratio supports oxygen cluster models for thermal donors but does not support previous suggestions that such clusters are embryonic forms of high temperature oxygen precipitates.

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