How is gallium arsenide formed from elements in the periodic table?

Gallium arsenide (GaAs) is a synthetic binary compound classified as a III-V semiconductor, meaning it is formed by combining gallium (a metal from column III of the periodic table) and arsenic (a nonmetal from column V).12

Because these elements must be combined precisely to form a high-quality crystal, several specialized growth methods are used in electronics manufacturing:

• Vapour Growth: Crystals can be grown by flowing a supersaturated gas over a seed crystal. In this process, chemical reactions at the surface deposit atoms; for example, gallium may be delivered via gallium chloride (GaCl) or trimethylgallium, while arsenic is provided by molecules such as arsine (AsH${}_3$) or arsenous chloride (AsCl${}_3$).3
• Epitaxy: This technique involves growing the crystal layer by layer on a substrate. Methods include molecular-beam epitaxy (MBE), which uses beams of atoms, and chemical vapour deposition (CVD), which uses flowing gases.4
• Liquid-Phase Epitaxy (LPE): This method uses a solution with a saturated concentration of the solute to grow the crystal on a substrate.4

These processes are essential for creating the high-purity materials required for optoelectronic and radio frequency applications.15