epitaksisesti

Epitaxy is a process in materials science and solid-state physics where a crystalline film is grown on a crystalline substrate. The term "epitaxy" comes from the Greek words "epi," meaning "upon," and "taxis," meaning "ordered." This process is crucial in the fabrication of semiconductor devices, optical coatings, and other advanced materials.

In epitaxy, the orientation and lattice parameters of the deposited film are influenced by the underlying substrate. This results in a highly ordered and coherent interface between the film and the substrate. The quality of the epitaxial film depends on several factors, including the lattice mismatch between the film and the substrate, the growth temperature, and the deposition technique used.

There are two main types of epitaxy: homoepitaxy and heteroepitaxy. Homoepitaxy occurs when the film and the substrate are made of the same material, while heteroepitaxy involves the growth of a film on a substrate of a different material. Heteroepitaxy is particularly challenging due to the lattice mismatch, which can lead to the formation of defects such as dislocations and stacking faults.

Epitaxy is typically achieved using techniques such as molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and pulsed laser deposition (PLD). These methods allow for precise control over the growth conditions, enabling the fabrication of high-quality epitaxial films with tailored properties.

The applications of epitaxy are vast and include the development of advanced semiconductor devices, such as high-electron-mobility transistors (HEMTs) and quantum wells, as well as the creation of optical coatings for lasers and other photonic devices. Epitaxy continues to be a fundamental process in the advancement of materials science and technology.