I. The Chemical Nature and Core Properties of Silane
Silane (SiH₄) is a compound formed by silicon and hydrogen. It belongs to the family of silicon-hydrogen compounds (general formula SiₙH₂ₙ₊₂), of which monosilane (SiH₄) is the most common. Its molecular structure is similar to that of methane, but the silicon atom has a larger radius and lower electronegativity. This results in a significantly weaker Si-H bond energy (approximately 318-384 kJ/mol) than a C-H bond (413 kJ/mol), endowing silane with extremely high chemical reactivity. At room temperature, silane is a colorless gas with a strong pungent odor. It has a melting point of -185°C and a boiling point of -112°C. It is spontaneously ignitable in air and rapidly reacts with water to form silicon oxide and hydrogen. At high temperatures (>400°C), it decomposes into silicon and hydrogen.

II. Silane Preparation Process and Purity Grading
Silane preparation technology directly impacts its purity and application areas. Current mainstream processes include:
Magnesium silicide method: Silane is produced by reacting magnesium silicide (Mg₂Si) with ammonium chloride (NH₄Cl) in liquid ammonia. This method is low-cost but has limited purity, making it suitable for the photovoltaic industry.
Trichlorosilane disproportionation method: Silicon tetrachloride (SiCl₄) is used as a raw material, undergoing hydrogenation and disproportionation reactions to produce high-purity silane (purity reaching 9-11N). This is the preferred process in the semiconductor industry.
Sodium aluminum hydride method: Silane tetrafluoride (SiF₄) is reacted with sodium aluminum hydride (NaAlH₄). The byproduct can be recycled, making it suitable for large-scale production.
Based on purity, silane is divided into industrial grade (3N-4N) and electronic grade (6N and above). Electronic grade silane has extremely stringent impurity requirements (e.g., metal ion content <1 ppb), requiring purification through precision distillation, adsorption, and other techniques.

III. Diverse Applications of Silane
Semiconductor Industry: Silane is a core silicon source in the chemical vapor deposition (CVD) process, used to prepare thin-film materials such as single-crystal silicon and polycrystalline silicon epitaxial wafers, silicon dioxide (SiO₂), and silicon nitride (Si₃N₄). It is widely used in integrated circuits, power devices, and other fields.
Photovoltaic Industry: Silane is a key raw material for crystalline silicon solar cells and amorphous silicon thin-film cells. CVD technology is used to deposit anti-reflective coatings and light-absorbing layers, improving cell conversion efficiency.
Display Panels: In TFT-LCD production, silane is used to deposit the insulating and semiconductor layers of thin-film transistors (TFTs), ensuring high resolution and low power consumption of display panels.
Emerging Fields: Silane is also used in the manufacture of specialty glass, photoelectric sensors, optical fibers, and as a raw material for high-energy materials and biomaterials. Its application scope continues to expand.