Kinetics of solid phase epitaxial regrowth in amorphized Si0.88Ge0.12measured by time‐resolved reflectivity

1993 ◽  
Vol 62 (5) ◽  
pp. 501-503 ◽  
Author(s):  
C. Lee ◽  
T. E. Haynes ◽  
K. S. Jones
1992 ◽  
Vol 281 ◽  
Author(s):  
T. E. Haynes ◽  
C. Lee ◽  
K. S. Jones

ABSTRACTThe rate of solid-phase epitaxial regrowth has been studied using time-resolved reflectivity in three different types of SiGe/Si epilayers amorphized by ion implantation. In two of these cases, the alloy epilayer contained either 12% or 20% Ge, and the amorphization depth was greater than the thickness (2000 Å) of the SiGe alloy layer. Time-resolved reflectivity measurements showed that the rate of regrowth was not constant in these two cases, but first decreased after passing the SiGe/Si interface, and then increased. The minimum regrowth rate occurred closer to the SiGe/Si interface in the epilayers with the larger Ge atomic fraction. In the third type of sample, the alloy epilayer thickness was ∼7μm, so that the initial epilayer (15% Ge) had the lattice constant of the bulk alloy. Furthermore, amorphization and regrowth occurred entirely within the relaxed alloy layer. In this case, the regrowth rate was constant. The composition dependence of the regrowth-rate transient in the strained layers is discussed in the context of a ‘critical-thickness’ model of strain relaxation.


2000 ◽  
Vol 364 (1-2) ◽  
pp. 228-232 ◽  
Author(s):  
M. Bauer ◽  
M. Oehme ◽  
M. Sauter ◽  
G. Eifler ◽  
E. Kasper

1994 ◽  
Vol 357 ◽  
Author(s):  
Todd W. Simpson ◽  
Ian V. Mitchell ◽  
Ning Yu ◽  
Michael Nastasi ◽  
Paul C. Mcintyre

AbstractTime resolved optical reflectivity (TRR) and Rutherford backscattering spectrometry (RBS) and ion channelling methods have been applied to determine the crystallization kinetics of Fe-doped A1203 in the temperature range of 900-1050°C. Amorphous A1203 films, approximately 250 nm thick and with Fe cation concentrations of 0, 1.85, 2.2 and 4.5%, were formed by e-beam deposition on single crystal, [0001] oriented, A1203 substrates. Annealing was performed under an oxygen ambient in a conventional tube furnace, and the optical changes which accompany crystallization were monitored, in situ, by TRR with a 633nm wavelength laser.Crystallization is observed to proceed via solid phase epitaxy. An intermediate, epitaxial phase of -γ-Al203 is formed before the samples reach the ultimate annealing temperature. The 5% Fe-doped film transforms from γ to α-A1203 at a rate approximately 10 times that of the pure A1203 film and the 1.85% and 2.2% Fe-doped films transform at rates between these two extremes. The Fe-dopants occupy substitional lattice sites in the epilayer. Each of the four sets of specimens displays an activation energy in the range 5.0±0.2eV for the γ,α phase transition.


1996 ◽  
Vol 439 ◽  
Author(s):  
J. C. McCallum

AbstractThe kinetics of intrinsic and dopant-enhanced solid phase epitaxy (SPE) have been measured in buried amorphous Si (a-Si) layers produced by ion implantation. Buried a-Si layers formed by self-ion implantation provide a suitable environment for studies of the intrinsic growth kinetics of amorphous Si, free from the rate-retarding effects of H. For the first time, dopant-enhanced SPE rates have been measured under these H-free conditions. Buried a-Si layers containing uniform As concentration profiles ranging from 1–16.1 × 1019 As.cm−3 were produced by multiple-energy ion implantation and time resolved reflectivity was used to measure SPE rates over the temperature range 480–660°C. In contrast to earlier studies, the dopant-enhanced SPE rate is found to depend linearly on the As concentration over the entire concentration range measured. The SPE rate can be expressed in the form, v/vi(T) = 1 + N/[No exp(-ΔE/kT)], where vi(T) is the intrinsic SPE rate, N is the dopant concentration and No = 1.2 × 1021 cm−3, ΔE = 0.21 eV.


1985 ◽  
Vol 52 ◽  
Author(s):  
C. Licoppe ◽  
Y. I. Nissim ◽  
C. Meriadec

ABSTRACTSolid phase epitaxial (SPE) growth of ion implanted GaAs layers has been studied using the time resolved reflectivity technique. A series of implanted impurities have been selected to study the dependance of the nature of the impurity on the growth kinetics. It has been found that the activation energy and the kinetics of growth were independant on the choice of implanted substitutional impurity. Only impurities such as Argon were responsible of a large decrease in the regrowth rate. The same technique is shown to bring informations on the amorphous-crystal interface structure during growth. From these informations it has been possible to show that interface roughening occured during SPE in (100) GaAs. This interface evolution is an intrinsic property of the implanted GaAs material.


1984 ◽  
Vol 35 ◽  
Author(s):  
P.K. Vasudev ◽  
A.E. Schmitz ◽  
G.L. Olson

ABSTRACTWe report on a systematic study of the doping profiles resulting from rapid thermal annealing of boron and BF2+-implanted silicon samples that were preamorphized by Si+ implantation. A two-step process consisting of an initial solid phase epitaxial regrowth followed by a brief (~5 sec) high temperature (1050ଌ) anneal produces extremely shallow (<1500Å) junctions with low defect concentrations. The quality of the epitaxial regrowth is very sensitive to implant conditions and impurity effects as deduced from time-resolved reflectivity measurements. Using the best conditions for implantation and solid phase crystallization, we have obtained boron-doped regions with sheet resistivities of 40 Ω/ and BF2-doped regions of resistivity 60 Ω/.


1994 ◽  
Vol 9 (12) ◽  
pp. 3113-3120 ◽  
Author(s):  
J. Rankin ◽  
B.W. Sheldon ◽  
L.A. Boatner

The solid-state epitaxial-regrowth kinetics of ion-beam-amorphized SrTiO3 surfaces annealed in water-vapor-rich atmospheres have been studied using time-resolved reflectivity (TRR). For this material, the conversion of the reflectivity-versus-time data obtained from the TRR measurements to recrystallized depth-versus-time data is more complicated than in systems such as silicon, where the reflectivity can be fit by assuming that the refractive index N (N = n + ik) in the amorphous layer is constant. In SrTiO3, agreement between measurements made directly with Rutherford backscattering spectroscopy (RBS) and those made using TRR can be obtained only when N is permitted to vary within the amorphous layer, with nonzero values for both the real and imaginary components. In some cases, the roughness of the amorphous/crystalline interface must also be considered. Additionally, a model for H2O-enhanced epitaxial regrowth is presented, which is in good agreement with the shape of the depth-versus-time profiles that are obtained from the TRR data.


1986 ◽  
Vol 74 ◽  
Author(s):  
J. A. Roth ◽  
G. L. Olson

AbstractThe effects of intentionally introduced impurities on the crystallization time, nucleation rate and crystallite growth velocity during solid phase random crystallization of amorphous Si thin films have been determined. Films deposited in UHV onto oxidized Si wafers were subjected to multiple energy ion implantation to introduce uniform distributions of P, B, As, O or F at 0.1–1.0 at.%. Crystallization times and growth velocities were determined over the temperature range 650 to 850°C from time-resolved reflectivity measurements, and nucleation rates were determined from these data using a classical, steady state nucleation and growth model. Strong impurity effects are observed: P, B and As all decrease the nucleation rate but accelerate the growth of crystallites, whereas both 0 and F retard growth while enhancing nucleation. The largest effects are for P, which reduces the nucleation rate more than 100 times at 1% concentration, and F, which increases the rate by roughly the same amount.


1996 ◽  
Vol 438 ◽  
Author(s):  
J. C. McCallum

AbstractThe kinetics of intrinsic and dopant-enhanced solid phase epitaxy (SPE) have been measured in buried amorphous Si (a-Si) layers produced by ion implantation. Buried a-Si layers formed by self-ion implantation provide a suitable environment for studies of the intrinsic growth kinetics of amorphous Si, free from the rate-retarding effects of H. For the first time, dopant-enhanced SPE rates have been measured under these H-free conditions. Buried a- Si layers containing uniform As concentration profiles ranging from 1–16.1 × 1019 As.cm-3 were produced by multiple-energy ion implantation and time resolved reflectivi[ty was used to measure SPE rates over the temperature range 480–660°C. In contrast to earlier studies, the dopant-enhanced SPE rate is found to depend linearly on the As concentration over the entire concentration range measured. The SPE rate can be expressed in the form, v/vi(T) = 1 + N/[No exp(−Λ E/kT)], where vi(T) is the intrinsic SPE rate, N is the dopant concentration and No = 1.2 × 1021 cm-3, ΔE = 0.21 eV.


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