The major application of silane sih4 in solar cell production can be seen in the deposition of amorphous silicon (a-Si), preparation of passivation layer and optimization of high-efficiency cell structure. Taking PERC (passivated emitter and back contact) batteries as an example, the back surface has to deposit a hydrogenated amorphous silicon (A-Si :H) layer with a thickness of about 10-15nm, and the silane sih4 consumption is about 0.8-1.2 grams per square meter of silicon, which accounts for 3.5%-4.5% of the cost of battery materials. As of 2023, the worldwide TOPCon battery capacity for production stands at 380GW, 5.3 tons of silane sih4 per GW per year of demand is in excess of 2000 tons, which increases the market price of silane to $1800-2200 / kg (≥99.9999% purity) from 32% above that of 2020.
Silane sih4 deposits p-i-n junctions via plasma enhanced chemical vapor deposition (PECVD) thin film deposition. Centrotherm PECVD tools possess the ability of a ≥1.5 nm/s deposition rate, increasing silane usage to 78% (versus 65% for conventional tools) and doubling the daily capacity of one device from 4,800 to 5,500 pieces (156mm size). Longi Green Energy 2024 HJT battery mass production line data show that the use of high-purity silane sih4 (≤ 0.1ppb metal impurities) will increase the conversion efficiency to 25.6% from a rise of 0.8 percentage points, and reduce the cost per watt by $0.02. For example, Hanwha Q CELLS in South Korea suffered from high oxygen content of silane (> 2 ppm), which caused the module power decay rate to rise from 0.5%/year to 2.3%/year and the after-sales cost rise by $12 million each year.
The passivation technology plays a stronger effect on the battery efficiency. Silane-derived silicon hydride nitride (SiNx:H) as an antireflective coating can reduce reflectance of incident light from 35% to 3% and achieve surface passivation lifetime > 2 ms. In the production of cadmium telluride (CdTe) modules of First Solar in the USA, 80nm SiNx:H coating is sputtered on each square meter of glass substrate, utilizing 0.6 grams of silane sih4, and flow ratio of ammonia (NH3) is controlled at 1:4, thereby so that film stress is stable between -200 MPa and +100 MPa. Prevent cracking risk. The 2023 JinkoSolar Tiger Neo module adopts double-layer SiNx:H technology to elevate the double-sided ratio from 70% to 85% and power gain of output to 4.7%, leading its global market share to 16.2%.
Technology refinements further boost silane sih4’s value chain. In perovskite/silicon laminated cells, silane sih4 is used to deposit a tunneling oxide layer (thickness < 1.5nm), and experimental results from Oxford Photovoltaic 2024 show that the structure can increase the open circuit voltage (Voc) of the cell up to 1.92V, and efficiency is higher than 33.7%. However, because of the explosive and flammable properties of silane, the storage system must be SEMI S6 compliant. For example, JA Technology Yangzhou factory spent 4.5 million US dollars to rebuild silane gas supply system, improving leak detection precision to 0.1ppm, reducing emergency cut-off reaction time to 0.2 seconds, and ensuring the normal operation of 10GW HJT’s annual production line.
Supply chain resilience has direct implications for industrial configuration. The 2024 Russia-Ukraine war led to a 28 per cent rise in the price of the electronic grade silane raw material, SiHCl3, that forced companies such as REC Silicon to push the cost of silane production to $1,450 / kg. For this end, GCL Integrated and South Korea OCI joint venture to build an output of 500 tons per year of silane plant, using the fluidized bed method (FBR) process, energy use from the traditional Siemens process of 120 kWh/kg to 65 kWh/kg, carbon emissions reduced by 54%, but equipment investment of 280 million US dollars, three years full production to break even. With the carbon neutral target by the world, the International Energy Agency prediction of installed solar PV demand by 2030 stands at 800GW, equivalent to the size of the silane sih4 market or more than 1.5 billion US dollars, technology substitution risks (such as aluminum doped zinc oxide) and safety concerns will continue to redefine its industrial position.