EPITAXIAL CRYSTALLIZATION DURING 600-DEGREES-C FURNACE ANNEALING OF AMORPHOUS SI LAYER DEPOSITED BY LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION AND IRRADIATED WITH 1-MEV XE IONS
J. Nakata, EPITAXIAL CRYSTALLIZATION DURING 600-DEGREES-C FURNACE ANNEALING OF AMORPHOUS SI LAYER DEPOSITED BY LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION AND IRRADIATED WITH 1-MEV XE IONS, Journal of applied physics, 82(11), 1997, pp. 5446-5459
The amorphous Si layers deposited by low-pressure chemical vapor depos
ition on (100)-crystal-Si substrates and subjected to Xe-ion-beam irra
diation are crystallized epitaxially in a layer-by-layer fashion to th
e surface during 600 degrees C furnace annealing. Layer-by-layer cryst
allization can be accomplished by irradiating the layers with a 1-MeV
Xe-ion-beam for a 2 x 10(15)/cm(2) dose at 310 degrees C prior to furn
ace annealing. In all cases during furnace annealing that amorphous Si
layers are polycrystallized or are grown vertically in isolated epita
xial-columnar-structures and then grown laterally into the amorphous r
egion surrounding each column, the ion-beam-induced epitaxial crystall
ization (IBIEC) method epitaxially crystallizes them in a layer-by-lay
er fashion. This is because O atoms that were at the initial interface
and that prevented layer-by-layer crystallization or columnar-epitaxi
al-growth diffuse remarkably because of irradiation. This diffusion de
creases the peak concentration and facilitates layer-by-layer crystall
ization. O atoms at the interface are also diffused by irradiation wit
h XO-keV P, 100-keV As, and 150-keV As ions. This diffusion results in
the columnar growth during 600-800 degrees C furnace annealing. Wheth
er layer-by-layer growth or columnar growth occurs during the furnace
annealing depends on the peak concentration of oxygen at the interface
. Direct evidence is shown that O diffusion is enhanced by the amount
of inelastic electronic scattering of incident ion beam under the same
elastic nuclear scattering conditions. The rates of IBIEC and of epit
axial crystallization during furnace annealing after 1-MeV Xe-ion-beam
irradiation for a 2 x 10(15)/cm(2) dose are affected by the amount of
oxygen in the amorphous layer. The rate of layer-by-layer IBIEC using
a 1-MeV Xe-ion-beam is nearly twice as high for a sample heated in th
e deposition furnace after evacuation as it is for a sample heated bef
ore evacuation. This difference is due to the smaller amount of oxygen
in the amorphous Si layer of the former sample. (C) 1997 American Ins
titute of Physics.