Physical Properties

State and Appearance: Silane is a colorless gas at room temperature and pressure.

Odor: Has an unpleasant, pungent odor.

Density: Slightly lighter than air (vapor density approximately 0.68, air = 1).

Boiling and Melting Points: Silane has a very low boiling point of approximately -112°C and a melting point of -185°C. This indicates that it vaporizes readily at room temperature.

Solubility: Slightly soluble in water, but readily soluble in many organic solvents.

Stability: Pure silane is stable at room temperature, but decomposes rapidly in the presence of impurities or elevated temperatures.

Its main application areas are as follows:

1. Semiconductor Industry (Core Applications)

This is the earliest and most important application area for silane.

Chemical Vapor Deposition (CVD): Silane is thermally decomposed within a reaction chamber (typically at low pressure and on a heated wafer surface), producing a high-purity polycrystalline or amorphous silicon thin film that coats the wafer surface.

Purpose: These silicon films are used to manufacture core components such as transistor gates, internal conductive layers (interconnects), and capacitors.

Epitaxial Growth: Silane is decomposed to form a new, continuous single-crystal silicon layer on a single-crystal silicon substrate.

Purpose: Used as the foundation for manufacturing high-performance transistors and integrated circuits.

2. Photovoltaic Industry (Solar Cells)

This is the largest consumer of silane.

Preparing amorphous silicon thin-film solar cells: Silane gas is decomposed on substrates such as glass, stainless steel, or plastic, depositing a very thin layer of amorphous silicon.

Advantages: This technology significantly reduces the amount of silicon used (lowering costs), is lightweight, and allows for flexible production. It is commonly used in computers, rooftop photovoltaic systems, and large-scale solar power plants. Polysilicon Raw Material Preparation: The decomposition of high-purity silane is one of the key methods for producing high-purity solar-grade polysilicon. This polysilicon is then pulled or cast into ingots and wafers for traditional solar cell manufacturing.

3. Flat Panel Display Industry

Thin-Film Transistor (TFT): In liquid crystal displays (LCDs) and OLED displays, each pixel is controlled by a TFT. Silane is used to deposit the amorphous silicon or polycrystalline silicon active layer that constitutes the TFT on a glass substrate.

Passivation and Insulation Layers: Silane reacts with nitrous oxide (N₂O) and other gases to deposit silicon dioxide (SiO₂) thin films, which serve as insulating and protective layers in display screens.

4. Other Applications

Silicon Nitride Thin Film Deposition: Silane reacts with ammonia (NH₃) to form a hard silicon nitride (Si₃N₄) thin film on the surface of chips. Functions: Serves as an excellent passivation layer (protecting the chip's internal circuitry from moisture and ion contamination), a mask layer (blocking impurities during ion implantation), and an insulating layer.

Powder Metallurgy and Ceramic Composites: The silicon produced by the decomposition of silane can penetrate porous materials to form silicide or silicon nitride, significantly improving the material's strength, hardness, and heat resistance.

Optical Fiber: Used in optical fiber manufacturing to deposit high-purity silica glass layers.

Chemical Synthesis: Serves as a starting material for the synthesis of other organosilicon compounds.