Materials scientist and physicist Dr Tuomo Suntola, recently won the Millennium Technology Prize 2018 for his invention of atomic layer deposition (ALD).

Dr Tuomo Suntola (right)

From laptops to smartphones, many of the electronic devices that we take for granted today would not have been possible without the work of Finnish materials scientist and physicist Dr Tuomo Suntola.

In the early 1970s, Dr Suntola developed a way of producing ultra-thin films, one atomic layer at a time that can be used to coat the surface of any material. This technique, called atomic layer deposition (ALD), has been used to improve the performance of computer chips, create high-efficiency solar power cells, and even protect coins and telescope mirrors.

It also enabled modern nanometre-scale integrated circuits, which are essential components in virtually all-modern computers and smartphones, and many other electronic equipment. Today, the market value of consumer electronics that rely on the technique exceeds US$500 billion (S$684.5 billion). For his far-reaching work, Dr Suntola was awarded the biennial Millennium Technology Prize, considered the Nobel Prize of technology, in 2018.

Dr Suntola, who will be a speaker at the Global Young Scientists Summit (GYSS) 2019, to be held in Singapore from 20 to 25 Jan, said that ALD could also play a key role in creating the next generation of batteries for electric vehicles and other products. “It can also be used for the manufacturing of new materials with as-yet unknown properties,” he said.

A serial inventor

Even as a child, Dr Suntola was interested in technology. He built wooden miniature replicas of World War II fighter planes, his first transistor radio at the age of 12 when the first transistors became available in Finland, and graduated to constructing radios and audio amplifiers during his teenage years.

When Finland entered its second phase of industrialisation in the 1970s, his creation of a humidity sensor earned him attention from corporations, and in 1974 he joined Instrumentarium, an import company for medical instruments, to start a new research unit in it.

At the time, it was difficult to produce the thin films needed for electroluminescent flat panel displays desirable in medical monitoring systems. While looking at a periodic table, Dr Suntola got the inspiration for a process – which he later called ALD – that would enable the sequential build-up of zinc sulphide, the light-emitting material in the displays.

ALD involves placing an item, such as a wafer containing computer chips, into a reaction chamber, and then flooding the chamber with a gas that coats the item. This process is self-limiting because the gas can only stick, or adsorb, to the exposed surface areas of the item. Once those are covered, the adsorption stops.

A second gas is then fed into the chamber to react with the surface created by the first gas to form a new surface layer of only one-atom-thick on the item. This process can be repeated to build up layers of the new material until the desired thickness is achieved.

Since the technique uses vapours to saturate the surface of the item, it can be used to coat any three-dimensional surface and still produce uniform, highly-ordered layers. By using different combinations of gases, scientists can also create a variety of ultra-thin films with different properties.

“After we calculated the necessary vapour pressures, temperatures and other parameters for the sequential process to occur, we made the first test run in early September 1974, and it was very successful,” Dr Suntola recalled in an interview with Technology Academy Finland, the Millennium Technology Prize’s organiser, after his win.

In 1978, he and his team moved to consumer electronics company Lohja Oy. “One of the most memorable moments for me was at the Society for Information Displays conference in San Diego in 1980. We had published nothing about our work before the conference, and when we presented it there, it was a sensation. We received almost 4,000 product inquiries about it after the conference,” he said.

He continued: “The most important moment so far, however, has been the breakthrough of ALD in semiconductor manufacturing in the early 2000s. That moment is still ongoing.”

Labours of love

Even now, Dr Suntola is still involved in ALD applications. He is a co-owner and board member of Picosun Oy, a Finnish ALD technology company, as well as chairman of the Physics Foundations Society, and the author of several books on science.

His most recent book, The Short History of Science, was a labour of love. “I’ve always been interested in the fundamentals of physics, and, as a technologist, I like to understand the laws of nature behind theories. The book helps people to understand the path and choices that have led to the theories that we have today,” he explained.

The GYSS 2019 will be his first time attending the event. He said: “I like working with young people, not as a teacher or an advisor, but as a motivator for them to identify and trust their internal strengths. The GYSS is a unique occasion for such sharing of experience and open-minded curiosity.”