Silicon
The backbone of the global semiconductor industry
Silicon single crystals form the substrate for 95% of the world's integrated circuits, solar cells, and power electronics. Grown by the Czochralski method at 1420°C, a single flawless boule - pulled over 48 hours from a bath of molten silicon - becomes the foundation for thousands of chips. India imports 100% of its semiconductor-grade silicon. Raana Semiconductors is changing that.
Purpose & Use Cases
From raw material to crystal
How a Silicon single crystal is grown - step by step
Silicon Feedstock
Solar-grade polysilicon (~6N-9N purity) is loaded into a quartz crucible. The purity is optimised for photovoltaic efficiency while maintaining cost-effectiveness.
Melting
The silicon is heated to about 1410-1420°C in a Czochralski furnace under an inert argon atmosphere until it becomes a uniform molten liquid.
Seeding
A single-crystal seed (typically <100>) is dipped into the melt. The crystal orientation of the seed determines the structure of the growing ingot.
Necking (Dislocation Reduction)
A thin neck (~3-5 mm) is formed by pulling faster. This helps reduce dislocations, though requirements are less strict than semiconductor-grade crystals.
Shoulder (Diameter Expansion)
The pull rate and temperature are adjusted to gradually increase the crystal diameter to the target size (typically 150-210 mm or larger for solar wafers).
Body Growth (Constant Diameter)
The crystal is grown at a nearly constant diameter. Pull rate, crystal rotation, and crucible rotation are controlled for uniform growth. In solar CZ, emphasis is on high throughput and stable diameter, not ultra-low defect density.
Tailing & Cooling
The crystal diameter is reduced at the end to form a tail, then the ingot is detached. Controlled cooling minimises thermal stress and cracking before further processing.
Quality parameters at a glance
Key metrics from Raana's production-grade Silicon crystals
Raana Semiconductors has grown India's first 200mm Silicon single crystal boule using the Czochralski method - a milestone for any Indian private entity. Our facility, incubated at BARC and supported under the India Semiconductor Mission, produces semiconductor-grade Silicon wafers meeting international standards for resistivity, oxygen content, and defect density. This breaks India's complete dependence on Japan and the US for the most critical substrate material in electronics.
Why Silicon Matters to India
The India Semiconductor Mission targets domestic chip fabrication by 2027. But without domestic silicon wafers, every fab in India will remain dependent on imports from Japan, the US, and Taiwan. Silicon is the first link in the chain - and it has been missing from India's industrial base entirely.
Raana's Silicon Programme
Our Czochralski silicon growth facility operates under the BARC Technology Transfer MOU, giving us access to four decades of India's best crystal growth research. We are currently producing:
- 150mm boules for power electronics substrates
- 200mm boules for logic and memory substrate qualification
Target specification: resistivity 1-10 Ω·cm, oxygen < 10 ppma, EPD < 100/cm².
Frequently Asked Questions
What is a silicon single crystal and why is it important?
A silicon single crystal is a continuous crystal lattice with no grain boundaries, grown by the Czochralski method. It forms the substrate for over 95% of the world's semiconductors - CPUs, memory chips, power electronics, and solar cells.
Does India produce semiconductor-grade silicon crystals?
Yes - Raana Semiconductors is India's first private company to grow semiconductor-grade silicon single crystals using the Czochralski method, breaking India's complete dependence on imports from Japan and the US.
What sizes of silicon boules does Raana produce?
Raana produces 150mm boules for power electronics and 200mm boules for logic and memory substrate qualification - the largest silicon crystals grown privately in India.
What is the Czochralski process for silicon?
The Czochralski process involves melting high-purity polysilicon at 1420°C, dipping a seed crystal into the melt, and slowly pulling it upward while rotating to grow a large, dislocation-free single crystal ingot.
Interested in Silicon?
Contact our team for technical specifications and samples