On the Mechanisms Governing Aluminum-Mediated Solid-Phase Epitaxy of Silicon

Abstract

Mechanisms governing the aluminum-mediated solid-phase epitaxy of Si on patterned crystalline Si substrates have been identified by studying the deposited material as a function of growth conditions when varying parameters such as temperature, growth time, and layer-stack properties. Early growth stages can be discerned as first formation of ''free'' Si at the Al/a-Si interface, then diffusion of Si along the Al grain boundaries, nucleation at the Si substrate surface, nuclei rearrangement, and finally crystal growth. The acquired understanding is applied to control the selectivity and completeness of single-crystal growth in various sizes of contact windows to the Si substrate.

Growth mechanism of an aluminium-induced solid phase epitaxial (AI-SPE) Si0.5Ge0.5layer using in situ heating transmission electron microscopy

“…Here we adopted a thermodynamic model to analyse the mechanism of an epi-SiGe film on a crystalline Si substrate that has been applied for the growth mechanism of polycrystalline Si, Ge, or Si 1−x Ge x films on the non-crystalline substrate (glass). [15][16][17][18] Thermodynamic analysis shows precise prediction of the nucleation position of epi-SiGe in the AI-SPE process, which is in good agreement with the experimental results of in situ heating TEM. In the end of our paper, we demonstrate the fabrication of an economical Ge virtual substrate by growth of compositional gradient epi-SiGe layers using multi-run Al-SPE processes.…”

“…The detailed thermodynamic model for the Al-induced phase transformation with the stacking structure of a-Si 1−x Ge x /Al/glass has been analysed in previous reports. [15][16][17][18] But this stacking structure with a glass substrate (non-crystalline) leads to the poly-crystalline Si 1−x Ge x , [15][16][17][18] since crystalline nuclei can form via both TI-mediated and GB-mediated routes, i.e., the nucleation can take place at both the a-Si 1−x Ge x /Al interface and Al grain boundaries, which are unconstrained by the substrate. [24][25][26][27] Once the glass substrate (non-crystalline) is replaced with the sc-Si (100) substrate (crystalline), Fig.…”

Epitaxial growth of heavily boron-doped Si by Al(B)-induced crystallisation at low temperature for back surface field manufacturing

“…16,[18][19][20] The dissolved Si atoms therefore tend to accumulate and can be easily aligned with the lattice of the underneath crystalline substrate at interface 3. 21 In the later section, we will demonstrate that the solid phase epitaxy (SPE) mechanism is realized on mono-crystalline Si wafers by our B-AIC process.…”

Al-mediated Solid-Phase Epitaxy of Silicon-On-Insulator

“…The growth mechanism governing the selective epitaxial deposition of SPE-Si on Si has been described by a semi-empirical theory in [6]. In that work the SPE growth was localized and limited to filling contact window surfaces by patterning the α-Si/Al layer stack around the windows and optimizing growth parameters such as the total amount of α-Si, the Al thickness, and the anneal temperature.…”