Solidification of highly undercooled liquid silicon produced by pulsed laser melting of ion-implanted amorphous silicon: Time-resolved and microstructural studies

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · J. Mat. Res.; (United States)

DOI:https://doi.org/10.1557/JMR.1987.0648· OSTI ID:6254259

Lowndes, D H; Pennycook, S J; Jellison, Jr, G E; Withrow, S P; Mashburn, D N

Nanosecond resolution time-resolved visible (632.8 nm) and infrared (1152 nm) reflectivity measurements, together with structural and Z-contrast transmission electron microscope (TEM) imaging, have been used to study pulsed laser melting and subsequent solidification of thick (190--410 nm) amorphous (a) Si layers produced by ion implantation. Melting was initiated using a KrF (248 nm) excimer laser of relatively long (45 ns full width half maximum (FWHM)) pulse duration; the microstructural and time-resolved measurements cover the entire energy density (E/sub l/) range from the onset of melting (at approx. >0.12 J/cm/sup 2/) up to the onset of epitaxial regrowth (at --1.1 J/cm/sup 2/). At low E/sub l/ the infrared reflectivity measurements were used to determine the time of formation, the velocity, and the final depth of ''explosively'' propagating buried liquid layers in 410 nm thick a-Si specimens that had been uniformly implanted with Si, Ge, or Cu over their upper --300 nm. Measured velocities lie in the 8--14 m/s range, with generally higher velocities obtained for the Ge- and Cu-implanted ''a-Si alloys.'' The velocity measurements result in an upper limit of 17 ( +- 3) K on the undercooling versus velocity relationship for an undercooled solidfying liquid--crystalline Si interface. The Z-contrast scanning TEM measurements of the final buried layer depth were in excellent agreement with the optical measurements.

• Research Organization: Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6254259
• Journal Information: J. Mat. Res.; (United States), Journal Name: J. Mat. Res.; (United States) Vol. 2:5; ISSN JMREE
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
360605 -- Materials-- Radiation Effects
CHARGED PARTICLES
COPPER IONS
CRYSTAL STRUCTURE
CRYSTALLIZATION
ELECTROMAGNETIC RADIATION
ELECTRON MICROSCOPY
ELEMENTS
GERMANIUM IONS
HEATING
INFRARED RADIATION
ION IMPLANTATION
IONS
IRRADIATION
LASER-RADIATION HEATING
LAYERS
MELTING
MICROSCOPY
MICROSTRUCTURE
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLASMA HEATING
PULSED IRRADIATION
RADIATIONS
REFLECTIVITY
SEMIMETALS
SILICON
SOLIDIFICATION
SURFACE PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY
VISIBLE RADIATION