Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA
Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA
Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA
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Hetero<strong>epitaxial</strong> Growth <strong>of</strong> <strong>III</strong>-V Semiconductor on Silicon Substrates<br />
energy. In other words, mist dislocations are necessarily introduced to release<br />
the mismatch strain through defects formation [35].<br />
3.3 Epitaxial Growth <strong>of</strong> Lattice-Mismatched Layers<br />
The concept <strong>of</strong> monolithically <strong>epitaxial</strong> integration <strong>of</strong> <strong>III</strong>-V <strong>semiconductor</strong>s on Si<br />
substrates is not straightforward and very challenging due to the signicant dierences<br />
in basic material and crystal properties that exist between elemental silicon<br />
and <strong>III</strong>-V compounds [14]. In general, when two dierent crystalline materials<br />
are brought together by <strong>epitaxial</strong> mean like in MBE <strong>growth</strong>, the <strong>growth</strong> process<br />
is called then heteroepitaxy such as the <strong>growth</strong> <strong>of</strong> InAs on Si. As a result <strong>of</strong> the<br />
<strong>epitaxial</strong> integration, a hetero-interface is formed between the <strong>III</strong>-V materials and<br />
silicon in heterostructure junctions [32]. Heteroepitaxy diers from homoepitaxy<br />
in that it requires the nucleation <strong>of</strong> a new phase on a foreign substrate. Because<br />
<strong>of</strong> this, the surface chemistry and physics play important roles in determining the<br />
properties <strong>of</strong> hetero<strong>epitaxial</strong> deposits, including structural and electrical characteristics,<br />
defect densities and structure, and the layer morphology [31]. However,<br />
the heteroepitaxy is classied for three main types based on the lattice constants<br />
<strong>of</strong> the two crystalline materials, lattice-matched heteroepitaxy for the same lattice<br />
constants and lattice-mismatched heteroepitaxy but elastically strained like<br />
InGaAs on GaAs for dierent lattice constants, and partially relaxed as in the<br />
case <strong>of</strong> the <strong>growth</strong> <strong>of</strong> InAs on silicon with high mist dislocation density. The<br />
heteroepitaxy process is widely used, not only for research but also for manufacturing<br />
<strong>semiconductor</strong> devices such as lasers, light emitting diodes (LEDs) and<br />
transistors.<br />
3.4 Challenges <strong>of</strong> Hetero<strong>epitaxial</strong> Growth <strong>of</strong> <strong>III</strong>-V<br />
on Silicon<br />
The physical material mismatch issues like lattice and thermal mismatches, and<br />
polar on non-polar natures between <strong>III</strong>-V material and Si undone all previous at-<br />
30