Raman measurements of lattice temperature in silicon under intense pulsed laser excitation
The lattice temperature rise in crystalline and ion-implanted silicon has been measured under pulsed laser annealing conditions. A heat-probe technique was used. The probe pulse (FWHM 7 nsec, lambda = 405 nm) with variable delay was provided by either a N/sub 2/ laser-pumped dye laser while the heat pulse was provided by a N/sub 2/ laser-pumped dye laser (lambda = 485 nm) or by a doubled Nd:YAG laser (FWHM 10 nsec, lambda = 532 nm). Lattice temperatures were inferred directly from the Stokes to anti-Stokes count ratio of the one-phonon Raman line. Suitable correction factors were applied to the Raman ratio to compensate for the spectral dependence of the Raman cross section and the absorption constant. A new experimental technique which is based on time-reversal invariance was developed to find the correction factors. Both power dependence (with power density up to 1 J/cm/sup 2/) and time-resolved (delay up to 900 nsec) temperature measurements were made. No Raman signal was observed during the high reflectivity phase. The maximum temperature rise observed within 10 to 20 nsec of the conclusion of the high reflectivity phase was 430 +- 75/sup 0/C. Measurements on ion-implanted silicon show that recrystallization is complete within 20 nsec of the conclusion of the high reflectivity phase. The temperature at this time was found to be 600 +- 200/sup 0/C. The anomalously low lattice temperatures show unequivocally that the high reflectivity phase is not associated with normal molten silicon unless an unreasonably large cooling rate is assumed. The results also point to the importance of electronic contributions to the pulsed annealing process.
- Research Organization:
- Kansas State Univ., Manhattan (USA)
- OSTI ID:
- 6014764
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON
CHEMICAL RADIATION EFFECTS
CRYSTAL LATTICES
RAMAN EFFECT
ANNEALING
ION IMPLANTATION
LASER RADIATION
LATTICE PARAMETERS
CHEMISTRY
CRYSTAL STRUCTURE
ELECTROMAGNETIC RADIATION
ELEMENTS
HEAT TREATMENTS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
SEMIMETALS
360605* - Materials- Radiation Effects