IIT-Bombay researchers develop first-ever indigenous semiconductor memory technology

A team of researchers at IIT-B led by Udayan Ganguly, professor in the department of electrical engineering, along with SCL have successfully demonstrated a CMOS-180nm-based 8-bit memory technology. This technology is adopted for production.

Researchers at the Indian Institute of Technology-Bombay (IIT-B) have invented the first-ever indigenous semiconductor memory technology that can be adopted for manufacturing at commercial unit of 180nm node in India.

The team at IIT-Bombay partnered with IIT-Delhi, SETS Chennai, and Defence Research and Development Organisation for hardware encryption. (HT FILE)

Memory is a critical aspect of the internet-of-things (IoT), a network of objects embedded with sensors or chips for exchange of data over a wireless network without the intervention of humans. Memories are used to customise chips by giving them user-specific storage of digital data. IoT connects tiny chips, which are all identical but distinguished by an identity (a barcode) stored in the memory. This data is stored within metal-insulator-metal (MIM) memory cells on a silicon integrated circuit memory chip.

At a time when IoT is disrupting the semiconductor industry worldwide, the semiconductor manufacturing ecosystem led by Semi-Conductor Laboratory (SCL), Mohali, department of space, Government of India, had to import the main technology from abroad.

However, a team of researchers at IIT-B led by Udayan Ganguly, professor in the department of electrical engineering, along with SCL have successfully demonstrated a CMOS-180nm-based 8-bit memory technology. This technology is adopted for production.

Ideally, silicon chips (like thermometers) should be identical, but manufacturing variations produce tiny offsets (such as errors in temperatures) which are revealed upon testing. This renders a large fraction of chips useless. The technology designed by the IIT-B team enables storing this tiny offset correction in memory once and applying it to the output afterward to make each imperfect chip perfect.

Using this method, generic chips can now be designed and make application-specific offsets added to make expensive custom chip design redundant, saving time and money for the user.

“One out of 100 ideas makes the journey from lab to fab. The exacting process of exceeding 95% yield requires an unrelenting multi-disciplinary team supported by a world-class R&D infrastructure to form an enduring collaboration. Once such successful technology opens possibilities of touching countless lives, in this case, through chips with a tiny memory,” said Ganguly.

This one-time programmable (OTP) memory is based on ultra-thin deposited silicon dioxide instead of the existing gate oxide-based OTP technology. In contrast to the high voltage required by gate oxide breakdown (a popular OTP memory), IIT-B’s memory chip requires less power and chip-area as the need for boosted voltage supply is avoided.

“Memory technology is critical to data security. It is essential for present and future Indian Fabs. To infuse innovation, translating memory technology from research to manufacturing is the key to compete globally and serve locally to establish a vibrant semiconductor ecosystem. The OTP Memory Technology Adoption for Trimming Application by the joint IIT-B-SCL, Chandigarh team is a pioneering step in this direction. It will be a game changer by enabling secure memory and encryption hardware for the country,” said VK Saraswat, member of NITI Aayog.

The project was initiated by the department of science and technology’s (DST) Intensification of Research in High Priority Area (IRHPA). Aspects of the work were funded by DST’s Nanoelectronics Network for Research and Applications (NNetRA), DST-Advanced Manufacturing Technologies, and office of PSA for hardware security. The team at IIT-B partnered with IIT-Delhi, SETS Chennai, and Defence Research and Development Organisation for hardware encryption.

“The success of the Digital India initiative by the Government of India has underpinnings in our country’s ability to manufacture electronics hardware. The focus on electronics hardware including integrated circuits or chips is key to strengthen R&D primarily in space and defence sectors. Development of standard, product design or IP development, and semiconductor manufacturing are increasingly important. Improving India’s participation in this area is a major priority for R&D in India. The partnership between IIT-B and SCL to establish this memory technology for the first time demonstrates the augmented potential for semiconductor research in the country,” said K Vijay Raghavan, principal scientific adviser (PSA) to the Government of India.