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 00:00:00 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), Vol. 2:5
• Country of Publication: United States
• Language: English

Related Subjects

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