“We Goal To Turn out to be The First Firm In India To Manufacture Photo voltaic-Grade Silicon Wafers Domestically”

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With regards to silicon wafer fabrication, strategies and their functions range, together with a posh process of purity evaluation. How an Indian startup with a number of patents is revolutionising this? Rajasekar Elavarasan of Raana Semiconductors tells every part to EFY’s Nitisha Dubey.

Q. What’s Raana Semiconductors’ specialisation, and who’re your goal clients?

A. We specialize in manufacturing crystal development machines, primarily designed for semiconductor-grade silicon wafers and superior crystals utilized in defence functions. Our merchandise play a key position in laser-guided missile techniques, underwater torpedo launch applied sciences, vary discovering and different specialised army functions. Our main clients embrace authorities entities such because the Division of Atomic Vitality (DAE), the Defence Analysis and Growth Organisation (DRDO), and the Centre for Supplies for Electronics Know-how (C-MET), which operates beneath the Ministry of Electronics and Info Know-how (MeitY). We provide crystal development machines and specialised crystals tailor-made for digital fabrication, terahertz functions, atomic radiation detection, and laser manufacturing, assembly the superior technological necessities of those sectors.

Q. Which approach is important for manufacturing silicon wafers?

A. The Czochralski approach is broadly used in the present day to supply silicon ingots, that are important for manufacturing silicon wafers. The method begins with polysilicon because the uncooked materials. This polysilicon is loaded right into a crucible, melting at a excessive temperature of round 1500°C. A seed crystal is then launched to the molten silicon, and as it’s slowly pulled upward, the silicon transitions from a liquid to a stable state, forming a single-crystal ingot. These ingots sometimes have a diameter of 300mm and may attain lengths of as much as three metres. After the ingot is fashioned, it undergoes a number of processing steps, together with slicing, lapping and sharpening, to rework it into silicon wafers. These wafers are substrates for microelectronic-grade IC fabrication, essential in producing fashionable digital parts.

Q. Why is the Czochralski technique most popular for producing silicon wafers?

A. The Czochralski technique is the dominant approach for producing silicon wafers bigger than 200mm. Strategies just like the Bridgman technique or the Float Zone course of are additionally used for wafers beneath 200mm. Nevertheless, the first limitation lies within the diameter of the silicon ingot, and Czochralski stays the one technique able to producing bigger diameter ingots.

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Q. What are the important thing strategies for producing different superior semiconductors?

A. Past silicon, compound semiconductors like silicon carbide (SiC) are gaining prominence, particularly in electrical automobiles, the place the Bodily Vapour Transport (PVT) technique is used for manufacturing. Equally, gallium oxide, one other rising materials, could be grown utilizing the Bridgman approach, although it’s restricted to a 50mm diameter. This materials exhibits promise for future semiconductor functions as a result of rising give attention to electrical automobiles. Moreover, sapphire is changing into an necessary substrate in quantum computing, the place photonics-based communication between ICs through laser gives speeds practically 10 instances quicker than conventional digital alerts. Sapphire waveguides can effectively transmit info, which is essential in enhancing quantum computing efficiency, the place light-based information transport outperforms electron-based strategies. These developments mirror the shift in the direction of high-performance semiconductors and quantum applied sciences.

Q. How does every approach guarantee crystal high quality and the general high quality of semiconductor supplies?

A. Every approach has its benefits and limitations. The Float Zone technique, as an example, eliminates the usage of a crucible, minimising contamination as the fabric by no means contacts any exterior floor. This method produces extremely pure and environment friendly silicon ingots and wafers, however its diameter vary is restricted. Whereas unsuitable for bigger functions, it’s splendid for sectors like defence and aerospace, the place materials effectivity is prioritised outsized. In distinction, the Czochralski technique permits for producing bigger silicon ingots important for microelectronic IC fabrication. Nevertheless, contamination can have an effect on the ingot’s high quality as the fabric contacts a quartz crucible. Strict high quality management is utilized to each the crucible and uncooked supplies. Nevertheless, some trade-offs between excessive purity and larger-diameter wafers are inevitable to satisfy the semiconductor business’s calls for.

Q. How does the Czochralski approach assist scale back impurities in crystal manufacturing?

A. Within the Czochralski approach used for silicon manufacturing, it’s essential to keep up low oxygen concentrations within the wafer, as larger oxygen ranges introduce impurities. A magnetic discipline is utilized throughout the course of to minimise these impurities. This magnetic discipline helps draw the impurities, inflicting them to settle on the backside of the crucible. We management impurities and oxygen focus utilizing this course of. Moreover, we rigorously management the expansion price and thermal gradient to minimise oxygen incorporation in silicon wafers. Our product, a specialised laser crystal, is manufactured utilizing the Czochralski approach, which we intend to provide to the Ministry of Defence (MoD), particularly the Ordinance Manufacturing unit.

Q. How does the pulling price impression crystal high quality, and why is it crucial for wafers?

A. The pulling velocity of a crystal varies relying on the fabric. For instance, silicon could be pulled at about 1 mm per minute. Nevertheless, the pulling price should be slower, round 0.5mm per hour, for different supplies like YAG or different oxide crystals. Exceeding the optimum pulling velocity for YAG crystal, akin to pulling quicker than 0.5mm per hour, can disrupt the formation of a single crystal. This could result in the inclusion of polycrystalline buildings, which degrade the crystal’s high quality. Silicon ingots with dislocation are more likely to be rejected. Subsequently, sustaining the standard of a single crystal all through the whole 3-metre (10-foot) ingot is important. With out correct crystal high quality, many wafers could also be rejected after slicing and wafering on account of polycrystalline inclusions.

Q. Why is the Czochralski approach most popular for large-diameter silicon wafer manufacturing?

A. The Czochralski approach is the one technique able to producing large-diameter silicon ingots with the specified crystal orientation, matching the best single-crystal orientation of the seed. On this course of, the oriented seed is dipped into the molten silicon to provoke crystal pulling, guaranteeing constant orientation all through the crystal. Different strategies, which don’t use a seed, end in random crystal orientations. Figuring out the specified orientation and extracting the right diameter from these crystals turns into advanced and tedious. Because of this the Czochralski approach is most popular for silicon wafers, particularly for diameters bigger than 20 centimetres (8 inches).

Q. What number of wafers are produced from an ingot and ready for fabrication?

A. Producing a 30-centimetre (12-inch) ingot of roughly 3 metres (10 toes) in size takes about three to 4 days and consumes round 150 kilowatts of vitality per hour. From a single ingot, roughly 6000 to 8000 wafers could be produced. These wafers are then lapped and polished, getting ready them to be used in semiconductor fabrication.

Q. Do you’ve gotten any patents?

A. Our firm has secured a number of patents, together with one targeted on pulling the silicon ingot at a chronic and managed price. The standard of a single crystal largely relies on this pull price. Our patented system allows us to attain an especially low pull price, as exact as 0.01mm per hour—equal to 1/a hundredth of a millimetre per hour. Along with sluggish pulling speeds, our system can deal with a most pull price of  500mm per minute. This big selection—from 0.01mm per hour to 500mm per minute—is managed utilizing a single motor due to our patented expertise.

One other key innovation we now have developed is an automated diameter management algorithm. This algorithm ensures that the diameter of the crystal stays uniform all through the pulling course of, which is crucial for each semiconductor and photo voltaic industries. The algorithm integrates open-core interface programming with closed-loop proportional-integral-derivative (PID) management techniques, permitting exact management over the diameter.

By means of this superior approach, we will produce high-quality monocrystalline silicon ingots. Within the silicon business, two primary sorts of crystals exist: polycrystalline and monocrystalline. Nevertheless, fashionable semiconductor and photo voltaic functions completely use monocrystalline silicon wafers, additional underscoring the significance of our expertise.

Initially filed in 2019, our patent underwent a number of hearings earlier than being granted in 2024. This patent covers the minimal pull price expertise and the automated diameter management algorithm, that are essential for producing high-quality monocrystalline silicon ingots that meet our clients’ evolving wants.

Q. How is the ND-YAG laser utilised throughout varied industries?

A. ND-YAG, or neodymium yttrium aluminium carbonate, is an oxide crystal able to producing laser beams. Lasers play an important position in varied fields, significantly in defence. They’re additionally broadly utilized in medical functions, akin to dental surgical procedure, skincare therapies, hair removing, and dermatology. Past healthcare, lasers have important functions in manufacturing, together with grinding and slicing processes. Recognising its versatility, we now have launched this India-manufactured laser as certainly one of our key merchandise, initially specializing in army wants, with plans to develop its use to civilian functions.

Q. How do you intend to provide each solar-grade and semiconductor-grade silicon wafers?

A. At present, our ND-YAG crystals and different crystal equipment are equipped to nationwide authorities laboratories and analysis centres. Nevertheless, we are actually scaling up our operations to supply 30-centimetre (12-inch) silicon wafers, aiming to offer each photo voltaic and semiconductor-grade wafers. We plan to fabricate solar-grade silicon wafers at present imported from China inside the subsequent 12 months. Though solar-grade wafers are of decrease high quality than semiconductor-grade, they’re appropriate for photo voltaic functions.

Our focus for the primary 18 months can be on producing large-diameter photo voltaic wafers. After that, we’ll improve the Czochralski approach to attain semiconductor-grade wafers, aiming to finish the method inside 36 months. As semiconductor fabs proceed establishing themselves in India, there can be rising demand for high-quality silicon wafers. The purpose is to develop into a number one home provider of those wafers, scale back reliance on imports, and place our firm on the forefront of India’s semiconductor manufacturing sector.

Q. What steps are you taking to scale up silicon wafer manufacturing in India?

A. Our operations are based mostly in Hosur, Tamil Nadu, the place we run a small facility for manufacturing 10-centimetre (4-inch) silicon wafers. With a crew of 15 to twenty members, our 280-square-metre (3000-square-foot) startup specialises in silicon wafer manufacturing and different crystals, akin to ND-YAG and PIEZO crystals, catering to Defence Analysis and Growth Organisation (DRDO) and atomic vitality necessities.

We’re scaling up, supported by grants from the MoD, to supply laser and semiconductor-grade crystals. Moreover, we’re pursuing personal fairness funding, primarily from enterprise capitalists, to develop our operations additional. We purpose to develop into the primary firm in India to fabricate solar-grade silicon wafers domestically, with plans to attain this inside 18 months. Following that, we try to transition to semiconductor-grade wafer manufacturing. Over the previous eight to 9 years, we now have equipped 26 machines to numerous authorities organisations. We’re dedicated to accelerating our progress to develop into pioneers in India’s silicon wafer manufacturing business.

Q. How does Raana Semiconductors handle element sourcing to make sure environment friendly manufacturing and top quality?

A. We deal with core system growth in-house whereas outsourcing processes like ASME (American Society of Mechanical Engineers) normal welding, machining, and different fabrication actions. Hosur, an industrial hub with a powerful presence within the car sector and precision engineering, together with TVS, Ashok Leyland, and TATA, gives a well-established vendor ecosystem specialising in high-precision equipment and parts. This permits us to outsource mechanical components based mostly on our designs for exterior fabrication.

As soon as the components are prepared, we assemble them at our facility, carry out crucial duties like graphite scorching zone meeting, and implement PLC (programmable logic controller) programming and automated diameter management algorithms—capabilities that set us aside from different firms. Establishing an in-house plant for these operations can be pricey, so outsourcing reduces bills and helps micro-enterprises in Hosur.

Q. How do you guarantee vendor high quality and scalability for wafer manufacturing and semiconductor manufacturing tools?

A. We at present have round 50 distributors and are working to extend this quantity to help the manufacturing of wafers and wafer manufacturing tools. Increasing our vendor base will assist us meet manufacturing timelines and safe aggressive pricing. Our focus is on figuring out dependable distributors to scale up our operations effectively.

In semiconductor manufacturing, all parts should be fabricated to satisfy particular requirements, akin to being corrosion-resistant, clear room and vacuum-compatible. Moreover, particular parameters, like sustaining Ra values for good floor end, should be carefully monitored. For parts like graphite heaters, high-purity graphite is essential, with impurity ranges saved to a minimal and purity reaching roughly 5 ppm. We rigorously validate distributors based mostly on materials purity and manufacturing processes to make sure they ship high-quality merchandise.

Q. What challenges hinder India’s progress in semiconductor manufacturing growth?

A. A key problem is guaranteeing a steady energy provide for semiconductor manufacturing. Moreover, there’s a rising want to satisfy the demand for expert manpower. Securing crucial parts presents one other hurdle, as some international locations strategically restrict exports, pushing us to develop these components domestically. This course of will take effort and time to yield the specified outcomes.

Regardless of these obstacles, I stay assured within the capabilities of the Indian scientific neighborhood and the sturdy help from the federal government. With sustained efforts, we anticipate overcoming these challenges inside the subsequent two to a few years. Trying forward, India has the potential to develop into a worldwide chief in semiconductor manufacturing inside the subsequent 5 years.

Q. What are your main focus areas for the long run?

A. Our focus is on producing semiconductor-grade silicon wafers to satisfy future business calls for. With firms like Tata-PSMC, Micron, LAM Analysis and others establishing fabrication items throughout India, the necessity for native wafer manufacturing is rising. India’s electronics manufacturing has tremendously progressed via backward integration, from assembling smartphones to packaging built-in circuits (ICs), with 40% of IC worth now added regionally.

Over the subsequent two to a few years, full-scale IC fabrication, together with wafer lithography, is anticipated in India. Aligned with our imaginative and prescient, we try to develop high-quality wafers to help the way forward for semiconductor manufacturing. Our purpose is to attain self-reliance throughout the whole worth chain—from wafer manufacturing to the manufacturing of end-semiconductor units—by 2028-2030.

Q. How did the enterprise carry out when it comes to development over the past fiscal 12 months?

A. We’re proper on observe. With practically 30% development and a stable pipeline of orders from defence and MeitY, ranging between ₹120 million and ₹150 million for 2025-26, we purpose for a turnover of ₹200 million in the identical interval. Plus, as we dive into manufacturing solar-grade tools and wafers, we’re taking a look at producing a formidable ₹3 billion to ₹4 billion in income.