Silane: The Next Big Thing in Special Gases

Industrial gas is called the blood of industry and plays a pivotal role. Among them, the “moat” of special gases is deeper, the technical barriers are higher, and it is both growth and periodic. Of course, there are many categories of special gases, the level of development is uneven, and the market space is also large and small. Today, we introduce a specialty gas whose demand is expanding rapidly – silane.

01 Where there is silicon, there is silane

Silane is a general term for a series of compounds composed of silicon and hydrogen. Strictly speaking, silane should refer to a large class of substances. However, in actual production, we generally refer to monosilane (chemical formula SiH4) as “silane”. This generalization can also be regarded as a “star effect”.

Silane has both ” gas ” and ” silicon-containing ” characteristics, and can generate crystalline silicon through pyrolysis reaction . Because of its high purity and fine control , it is an important specialty gas that cannot be replaced by many other silicon sources. Silane can be considered as “flowing pure silicon”. Therefore, silane is often used where there is silicon, including TFT ( thin film transistor )/ LCD ( liquid crystal display ), crystalline silicon solar cells , semiconductors and other applications. Emerging There are also many fields such as silicon carbon anode , advanced ceramics, composite materials, biological materials, etc., and silane almost takes over the entire new energy, semiconductor, and new material industries.

The silane used in photovoltaics requires a purity of more than 5N (five 9s, or 99.999%, the following is similar), the panel requires a purity of 6N , and the semiconductor requires a purity of 7-9N or more . Of course, every time the purity level increases, the cost will increase exponentially.

02 New energy brings warmth to silane

Since silane is expensive, it is obviously a waste of money to directly use silicon wafers or wafers. Therefore, silane is generally only used for surface treatment, forming thin films on substrates or silicon wafers by chemical vapor deposition (CVD) . Don’t underestimate this thin film, which can bring silane a market worth billions or even billions . In 2022, the market space for silane will be about 5,000 tons , of which photovoltaics will account for 60%-70%, and panels will account for 20%. This figure is expected to double rapidly.

The photovoltaic industry is the ballast stone of silane, and the photovoltaic industry is facingthe “Davis double-click” of the increase in installed capacity and the increase in the penetration rate of N-type cells . In recent years, photovoltaics have developed rapidly. According to the 2022 national power industry statistics released by the National Energy Administration, the newly installed photovoltaic capacity in the country will reach 87.41GW in 2022, setting a record high. Going a step further, the Photovoltaic Industry Association has raised the forecast for China’s new installed photovoltaic capacity in 2023 from 95GW-120GW to 120GW – 140GW , and raised the forecast for global installed photovoltaic capacity in 2023 from 280GW-330GW to 305GW-350GW.

The proportion of N-type silicon wafers is also continuously increasing. In 2022, the proportion of N-type silicon wafers will increase to 10% , and in 2023 it will further increase to 25%+ . Since the back of photovoltaic N-type cells adopts a tunneling oxide layer and polysilicon layer passivation contact structure, the amount of silane gas required is about 50% higher than that of P-type cells . Guotai Junan Research Report predicts that the amount of silane gas used in the photovoltaic industry will double in 2023 , up to 5888 tons, and will maintain continuous and rapid growth in the future.

In recent years, the demand in the panel industry has been relatively weak , but it has also maintained a certain rate of expansion. The demand for silane is expected to increase by more than 100 tons per year. The semiconductor industry has extremely high requirements on the purity of silane, silane has not yet been fully localized , and there are many loopholes in the semiconductor industry chain itself. Although the demand for silane is growing rapidly, the base is low, so the overall impact on silane is limited.

Silicon carbon anode is expected to become the second growth point of silane. Graphite negative electrode (not “graphene”) is currently the most widely used and mature negative electrode material, but its theoretical capacity is only 372mAh/g, and it has already approached the upper limit of energy density, making it difficult to meet the needs of new lithium-ion batteries for negative electrode materials , silicon-based anode materials with both high reversible capacity and high rate security are regarded as ideal next-generation anode materials. According to the data disclosed by the Lithium Battery Research Institute (GGII), the current silicon-carbon anode technology has achieved breakthrough technical indicators such as a gram capacity of 1800mAh/g and a cycle performance of more than 1000 times.

According to GGII data, my country’s shipments of silicon-based anode materials will be 11,000 tons in 2021, a year-on-year increase of 83.3%, and it is expected to achieve greater growth in 2023. Silicon carbon negative electrode is applied to CVD (vapor phase deposition method) to produce 1 ton of silicon carbon negative electrode masterbatch (silicon doping rate is about 50%, and downstream enterprises further compound silicon carbon negative electrode masterbatch with graphite and other materials to make silicon carbon anode masterbatch 5% according to demand. -10% silicon carbon anode material), need to use more than 0.6 tons of silane, for silane, it corresponds to the market space of hundreds of tons in the near future and thousands of tons in the long term .

03 Got windy

Like other special gases, the production of silane gas has the characteristics of high thresholds such as process technology , engineering practice, production experience, etc., and secondly, there are high barriers such as long certification period for downstream customers and large capital investment. Silane gas is explosive, toxic and difficult to store, and there are high safety and environmental protection barriers . Therefore, the number of silane companies is small, and it is relatively difficult to expand production, and the expansion period is more than one year . Under the condition of rapid release of downstream demand, it is expected to continue to maintain a state of short supply.

The silane industry also has a proud industry structure. The upstream of silane is silicon powder, silicon tetrachloride, hydrogen and other chemicals, which are relatively easy to obtain. For the upstream, silane accounts for a small and insensitive proportion of the downstream cost (only 1% to 0.1%). The silane industry has an important role for the downstream. Certain bargaining power , these can be found in the accounts receivable and payable of related enterprises.

The silane industry has also had a rough time. A few years ago, downstream industries such as photovoltaics had not developed rapidly. The silane market space is narrow, there is a lack of industry standards, the risk of technology path is high, there is vicious competition among enterprises, and the industry profits are extremely poor .

Today, the release of downstream demand such as photovoltaics has also brought the little-known silane into the public eye, and the silane industry has also ushered in a bright moment of rising volume and price.