Solid Phase Epitaxial Growth Process Research Articles

Lattice kinetic Monte Carlo modeling of germanium solid phase epitaxial growth

AbstractSolid phase epitaxial growth (SPEG) is a common tech¬nique used in the manufacturing processes of MOSFET technology. Even though a relatively broad knowledge is found for silicon, there is a greater uncertainty when it comes to germanium, which importance is arising in the last generation of microelectronic devices. To simu¬late this process, the need of a model which reproduces anisotropic growth and is able to detect and place twin defects becomes relevant, opening the possibility to sim¬ulate the interaction of different crystallographies, as it has been observed to be an important factor for some orientations, justifying by this mechanism experimental results.We present a Lattice Kinetic Monte Carlo (LKMC) model of Ge which is able to give an explanation of the different anisotropy effects in the recrystallization of substrate wafers through a defect formation formalism. An agreement between experimental observations and simulations is found by comparing regrowth velocities for different samples at different anneal conditions with LKMC simulations that consider twin defect formation for specific directions. Different regrowth velocities are found for distinct orientations of a solid phase epitaxial growth process within the annealed sample.(© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Substrate orientation dependence on the solid phase epitaxial growth rate of Ge

The solid phase epitaxial growth process has been studied at 330 °C by transmission electron microscopy for Ge wafers polished at 10°–15° increments from the [001] to [011] orientations. The velocity showed a strong dependence on substrate orientation with the [001] direction displaying a velocity 16 times greater than the [111] direction. A lattice kinetic Monte Carlo model was used to simulate solid phase epitaxial growth (SPEG) rates at different orientations, and simulations compared well with experimental results. Cross sectional transmission electron microscopy and plan view transmission electron microscopy revealed stacking fault and twin defect formation in the [111] orientation where all other orientations showed only hairpin dislocations. The twin defects formed from Ge SPEG were comparatively less dense than what has previously been reported for Si, which gave rise to higher normalized velocities and a constant [111] SPEG velocity for Ge.

A novel approach for preparing Fe(TexSy) superconducting films: solid phase epitaxial growth from amorphous precursors

Fe(TexSy) films were fabricated on (100) SrTiO3 substrates from Fe(Te0.65S0.16) amorphous precursors by a solid phase epitaxial growth process under various background atmospheric conditions. Structural analysis by x-ray diffraction showed strong peaks corresponding to Fe(TexSy) phases, when the amorphous precursors were heated with Fe(Te0.8S0.2) sintered pellets. The crystallinity of the films deteriorated at longer periods of heating but the compositional shifts were found to have decreased. Consequently, the critical temperature, TCzero, of the Fe(TexSy) film with minimum compositional shift was found to be 9.0 K and critical current density, JC, of the film was about 1.4 × 104 A cm−2.

Stressed multidirectional solid-phase epitaxial growth of Si

The study of the solid-phase epitaxial growth (SPEG) process of Si (variously referred to as solid-phase epitaxy, solid-phase epitaxial regrowth, solid-phase epitaxial crystallization, and solid-phase epitaxial recrystallization) amorphized via ion implantation has been a topic of fundamental and technological importance for several decades. Overwhelmingly, SPEG has been studied (and viewed) as a single-directional process where an advancing growth front between amorphous and crystalline Si phases only has one specific crystallographic orientation. However, as it pertains to device processing, SPEG must actually be considered as multidirectional (or patterned) rather than bulk in nature with the evolving growth interface having multiple crystallographic orientations. Moreover, due to the increasingly ubiquitous nature of stresses presented during typical Si-based device fabrication, there is great interest in specifically studying the stressed-SPEG process. This work reviews the progress made in understanding the multidirectional SPEG and, more importantly, stressed multidirectional SPEG process. For the work reviewed herein, (001) Si wafers with ⟨110⟩-aligned, intrinsically stressed Si3N4/SiO2 patterning consisting of square and line structures were used with unmasked regions of the Si substrate amorphized via ion implantation. It is revealed that the stresses generated in the Si substrate from the patterning, both in line and square structures, alter the kinetics and geometry of the multidirectional SPEG process and can influence the formation of mask-edge defects which form during growth to different degrees as per differences in the substrate stresses generated by each type of patterning. Likewise, it is shown that application of external stress from wafer bending during SPEG in specimens with and without patterning can also influence the geometry of the evolving growth interface. Finally, the effect of the addition of SPEG-enhancing impurities during multidirectional stressed growth is observed to alter the evolution of the growth interface, thus suggesting that stress influences on growth are much less than those from dopants. Within the context of prior work, attempts are made to correlate the prior observations in single-directional stressed SPEG with the observations from patterned stressed SPEG reviewed herein. However, as is argued in this review, it ultimately appears that much of the research performed on understanding the single-directional stressed-SPEG process cannot be reasonably extended to the multidirectional stressed-SPEG process.

Growth process and surface structure of MnSi on Si(1 1 1)

The solid-phase epitaxial growth process and surface structure of MnSi on Si(111) were investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS) and atomic force microscopy (AFM). For the Si(111) sample deposited with 30 monolayers (ML) of Mn at room temperature, the intermixing of Mn and Si gradually started at 100°C and reached equilibrium at approximately 400°C. At this equilibrium state, the Mn atoms were transformed into crystalline MnSi film. Further annealing caused the desorption of Mn atoms. We identified the structure of MnSi as cubic B20 and the crystallographic orientation relationships as Si(111)//MnSi(111) and Si[1¯21¯]//MnSi[1¯10]. The MnSi(111) surface was found to have a dense Si terminating layer on its topmost surface. On the other hand, 3ML of Mn deposited on Si(111) reacted with Si even at room temperature and formed a pseudomorphic structure. This structure was transformed into MnSi after annealing. A filmlike morphology with protrusions was observed for the sample with 30ML of Mn, while island growth occurred for the sample with 3ML of Mn.

Ion-beam-induced epitaxial crystallization (IBIEC) and solid phase epitaxial growth (SPEG) of Si 1− xC x layers in Si fabricated by C ion implantation

Amorphous Si 1− x C x layers in Si(100) (0.013 ≤ x ≤ 0.032 at peak concentration) formed by 35 keV 12C implantation were crystallized by solid phase epitaxial growth (SPEG) up to 850°C and by ion-beam-induced epitaxial crystallization (IBIEC) with 400 keV Ar or Ge ions at 300–400°C. SPEG process has induced the epitaxial growth up to the surface for samples with x ≤ 0.019 and IBIEC process has induced that for samples with x ≤ 0.025. Rutherford backscattering spectrometry (RBS) measurements have revealed a direct scattering peak due to extended defects around the depth of peak C concentration both in SPEG-grown samples ( x = 0.019) and IBIEC-grown sample ( x = 0.025). X-ray diffraction (XRD) has shown a growth with smaller tensile strain in both SPEG- and IBIEC-grown samples than in fully strained layers. Photoluminescence (PL) measurements at 2 K have shown a strong I 1 line emission in IBIEC-grown samples, which can be attributed to vacancy clustering. The local configuration of defects around C atoms in the IBIEC-grown samples is thought to be an origin of the smaller tensile strain.

Strain induced defects in Si 1− xGe x-alloy layers formed by solid phase epitaxial growth of 40 keV Ge + ion implanted silicon

High-dose Ge + ion implantation, together with Solid Phase Epitaxial Growth (SPEG), has been used to form Si 1− x Ge x -alloy layers in silicon crystals. The microstructure and crystal quality of the alloy layers were studied for 40 keV Ge + ion implantations in the dose range 9.3 × 10 15 to 3.4 × 10 16 ions/cm 2. The SPEG was carried out in a conventional furnace at 850°C in a flow of nitrogen gas. A regrowth of the ion implanted amorphous layer is achieved for all ion doses and a single crystal Si 1− x Ge x -alloy layer with no observable extended defects is obtained when the Ge + ion dose is lower than a critical value of about 2.3 × 10 16 ions/cm 2. This gives a critical areal strain energy density of about 235 mJ/m 2. Above the critical ion dose, extended defects are formed in the Si 1− x Ge x material during the recrystallisation process and the density of the defects increases with Ge + ion dose. Most of the defects are stacking faults lying parallel to the {111} planes. The defects are bound at the surface of the crystal in one end and with dislocations in the other end. The depth position of the dislocations obtained from the measurements agrees with a theoretical prediction based on the assumption that the defects are nucleated at the SPEG process when the crystalline/amorphous interface advances to the depth position in the crystal where the accumulated strain energy density in the recrystallised layer reaches the critical value. No appreciable glide of the dislocations into the already recrystallised layer is detected.

Ion-Beam-Induced Epitaxy and Solid Phase Epitaxy of Sigec on Si Formed by Ge and C Ion Implantation and their Structural and Optical Properties

AbstractEpitaxial layers of Si1-x-yGexCy on Si(100) (x=0.13 and y=0.014 at peak concentration) were formed by ion implantation of Ge ions and C ions at room temperature (RT) and by subsequent IBIEC (ion-beam-induced epitaxial crystallization) process with 400keV Ge and ar ions at 300-400°C and SPEG (solid phase epitaxial growth) process up to 840°C. Crystallization up to the surface both by IBIEC and SPEG processes has been confirmed with RBS-channeling analysis. X-ray diffraction experiments have demonstrated strain compensation by incorporation of C atoms for IBIEC-grown Si1-x-yGexCy/Si samples, whereas strain accommodation due to C precipitation has been observed for SPEG-grown Si1-x-yGexCy/Si samples. Photoluminescence (PL) observed at 2K from IBIEC-grown samples has shown intense I1 peak with/without I1 related (Ar) peak and that from SPEG-grown samples has shown G line emission. these optical properties could suggest that small vacancy agglomeration is dominant in IBIEC-grown samples and C agglomeration is dominant in SPEG-grown samples, respectively.

Recrystallization behavior of silicon implanted with iron

The solid phase epitaxial growth (SPEG) of amorphized Si layers implanted with Fe (1×1015 cm−2, 100 keV) was investigated in the temperature range from 500 to 550 °C using Rutherford backscattering spectrometry. The push-out of Fe atoms by the moving amorphous-crystalline (a-c) interface was observed during annealing, and enhancement of the recrystallization rate was induced by the presence of Fe. These results are discussed in terms of a model that assumes that Fe atoms are trapped in the amorphous layer and released when they are reached by the moving a-c interface during the SPEG process.