Time-Resolved Reflectivity Study of Solid-Phase Epitaxial Regrowth in Relaxed and Strained Si1−xGex Epilayers

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.

2017 ◽  
Vol 122 (10) ◽  
pp. 105702
Author(s):  
M. Prieto-Depedro ◽  
A. Payet ◽  
B. Sklénard ◽  
I. Martin-Bragado

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

1994 ◽  
Vol 373 ◽  
Author(s):  
M. Fyhn ◽  
S. Yu. Shiryaev ◽  
A. Nylandsted Larsen ◽  
J. Lundsgaard Hansen

AbstractSolid phase epitaxial regrowth of ion-implanted relaxed Si1-xGex layers was studied as a function of alloy composition (0.15< x <0.5) by a combination of Rutherford backscattering/ channeling spectrometry and transmission electron microscopy. The samples were grown by molecular beam epitaxy on compositionally graded buffers at different growth conditions. It was found that the regrowth velocity follows an Arrhenius curve in the investigated composition range and increases with increasing Ge content. The activation energies of the epitaxial regrowth were found to be higher than those expected from a linear interpolation between the values for pure Si and Ge. It is demonstrated that the regrowth velocities in the samples grown at 550 and 750°C and with low-rotational speed of the substrate during growth depend on the lateral position on the wafer and that they can be reduced by a preannealing treatment at high temperatures (σ920°C). We suggest that these effects arise from a compositional modulation in the alloy layer and, therefore, from a symmetrized strain, which can be reduced by a high temperature annealing.


1989 ◽  
Vol 160 ◽  
Author(s):  
B.J. Robinson ◽  
B.T. Chilton ◽  
P. Ferret ◽  
D.A. Thompson

AbstractSingle strained layer structures of up to 30 nm of Si1-xGex. on (100) Si and capped with 30-36 nm of Si have been amorphized by implantation with 120 keV As . The amorphized region, extending to a depth of 130 nm, has been regrown by solid phase epitaxy (SPE) at 600°C. Characterization of the regrown structure by Rutherford backscattering/channeling techniques and transmission electron microscopy indicates that for x < 0.18 the SPE process results in the recovery of strain, while for x > 0.18 there is increasing strain relaxation and a deterioration of crystal quality.


1991 ◽  
Vol 230 ◽  
Author(s):  
Roy Clarke ◽  
Waldemar Dos Passos ◽  
Walter Lowe ◽  
Brian Rodricks ◽  
Cristine Brizard

AbstractA new time-resolved x-ray method of probing the kinetics of interfacial strains in semiconductor heterostructures is presented. High-resolution synchrotron radiation measurements of the strain relaxation during rapid thermal annealing (RTA) show that the lattice strain of an as-grown strained layer structure GaAs-Inx.Ga1−x-As-GaAs/GaAs is relieved cooperatively by a series of sluggish discontinuous transitions. We find that ion implantation enhances the annealing kinetics of InAlAs strained layers.


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/.


1995 ◽  
Vol 379 ◽  
Author(s):  
M.J. Antonell ◽  
T.E. Haynes ◽  
K.S. Jones

ABSTRACTTransmission electron microscopy has been combined with time-resolved reflectivity and ion channeling to study the effects of regrowth temperature and carbon introduction by ion implantation on the solid phase epitaxial regrowth (SPER) of strained 2000Å, Sio.88Ge0.12/Si alloy films grown by molecular-beam epitaxy (MBE). Relative to the undoped layers, carbon incorporation in the MBE grown SiGe layers prior to regrowth at moderate temperatures (500- 700°C) has three main effects on SPER; these include a reduction in SPER rate, a delay in the onset of strain-relieving defect formation, and a sharpening of the amorphous-crystalline (a/c) interface, i.e., promotion of a two-dimensional (planar) growth front.1 Recrystallization of amorphized SiGe layers at higher temperatures (1 100°C) substantially modifies the defect structure in samples both with and without carbon. At these elevated temperatures threading dislocations extend completely to the Si/SiGe interface. Stacking faults are eliminated in the high temperature regrowth, and the threading dislocation density is slightly higher with carbon implantation.


1993 ◽  
Vol 316 ◽  
Author(s):  
Robert G. Elliman ◽  
Wah-Chung Wong ◽  
Per KringhØj

ABSTRACTThermally-induced solid-phase epitaxial crystallisation (SPEC) and ion-beam-induced epitaxial crystallisation (IBIEC) of amorphous GexSi1-x alloy layers is examined for three different starting structures: a) strain-relaxed alloy layers of uniform composition, b) strained alloy layers of uniform composition, and c) Ge implanted Si layers. Thermal annealing experiments show that the activation energy for strain-relaxed alloys is higher than that expected from a simple extrapolation between the activation energies of Si and Ge, and exceeds that of Si for x ≤ 0.3. Experiments on thin strained layers show that MBE grown strained layers which are stable during annealing at 1100°C for 60 s are also fully strained after SPEC, whereas layers which relax during annealing at 1100°C also relax during SPEC. Experiments on ion-implanted GeχSiι_x structures show that fully strained Si/GexSi1-x /Si heterostructures can be fabricated for ion fluences below a critical fluence, and as for uniform alloy layers that this critical fluence is accurately predicted by equilibrium theory. Strain relaxation during SPEC of uniform alloys and implanted structures is shown to be correlated with a sudden reduction in crystallisation velocity which is believed to be caused by stress-induced roughening or faceting of the crystalline/amorphous interface. IBIEC of thick (800 nm) implanted layers is shown to be limited by competition from ion-beam induced random crystallisation, while thin (120 nm) uniform alloys and implanted structures are shown to crystallise ephaxially and to exhibit similar behaviour to thermally annealed samples under certain conditions.


1995 ◽  
Vol 379 ◽  
Author(s):  
D.Y.C. Lie ◽  
J.H. Song ◽  
M.-A. Nicolet ◽  
N.D. Theodore ◽  
J. Candelaria ◽  
...  

ABSTRACTMetastable pseudomorphic GexSi1−x (x=8%,16%) films were deposited on p-Si(100) substrates by chemical-vapor-deposition and then implanted at room temperature with 90 keV arsenic ions to a dose of 1.5×1015/cm2. The implantation amorphizes approximately the top 125 nm of the 145 nm-thick GeSi layers. The Si-GeSi interfaces remain sharp after implantation. Implanted and non-implanted GeSi samples, together with implanted Si control samples, were subsequently annealed simultaneously by rapid thermal annealing in a nitrogen ambient at 600,700,800 × for 10,20,40s at each temperature. The implanted samples undergo layer-by-layer solid-phase epitaxial regrowth during annealing at or above 600 ×C. The amorphized and regrown GeSi layers are always fully relaxed with a very high density of dislocations (1010-1011/cm2). At a fixed annealing temperature, strain relaxation of an implanted GeSi film is substantially more extensive than that of a non-implanted one. About 50-90% of the implanted arsenic ions become electrically active after the completion of solid-phase epitaxy. The percentages of arsenic ions that are activated in the Si control samples are generally higher than those in GeSi. The room-temperature sheet electron mobility in GeSi is roughly 30% lower than that in Si for a given sheet electron concentration. We conclude that metastable GeSi on Si(100) amorphized by arsenic ions and recrystallized by solid-phase epitaxy cannot recover both its crystallinity and its pseudomorphic strain under rapid thermal annealing.


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