Polysilicon

• Polysilicon (Polycrystalline Silicon) is a highly purified form of silicon used as a basic raw material in the semiconductor and solar industries.
• It is produced by purifying metallurgical-grade silicon to very high levels of purity.
• Semiconductor-grade It is used to manufacture silicon wafers for integrated circuits and semiconductor chips.
• Solar-grade It is primarily used to manufacture photovoltaic (PV) cells.
• It is converted into ingots → wafers → cells → modules in the solar PV value chain.
• In semiconductor manufacturing, the broad chain is polysilicon → ingot → wafer → semiconductor fabrication → chip.
• Silicon (Si) is a semiconductor, meaning its electrical conductivity lies between that of conductors and insulators.
• It is not the same as silicon carbide (SiC) or gallium nitride (GaN), which are wide-bandgap semiconductor materials.
• It production is energy-intensive, making access to reliable and relatively inexpensive electricity important.
• China has a dominant position in global polysilicon production, making diversification of supply chains important for countries such as India.

Why Is Polysilicon Important for India?

• Solar Manufacturing: Reduces dependence on imported raw materials for domestic solar manufacturing.
• Semiconductor Ecosystem: It forms an important upstream component of the silicon-based semiconductor value chain.
• Energy Security: Greater domestic manufacturing can strengthen India’s renewable-energy supply chain.
• Strategic Autonomy: Diversified polysilicon supplies reduce vulnerability to external supply-chain disruptions.
• Viksit Bharat: Domestic production can support India’s goal of developing an integrated electronics and semiconductor ecosystem.

Prelims MCQ

Q. Consider the following statements regarding:

1. It is a highly purified form of silicon.
2. It is used in the manufacture of solar photovoltaic cells.
3. It is an important raw material for silicon-based semiconductor manufacturing.
4. It is a wide-bandgap semiconductor like silicon carbide.

Which of the statements given above are correct?

(a) 1, 2 and 3 only
(b) 1 and 4 only
(c) 2 and 3 only
(d) 1, 2, 3 and 4

Answer: (a) 1, 2 and 3 only

Explanation: It is a highly purified form of silicon and is important for both solar PV and semiconductor manufacturing. Silicon carbide, not polysilicon, is a wide-bandgap semiconductor.