Integrated circuits will increasingly be produced, not on pure silicon wafers, but on silicon on insulator, more commonly known as SOI.
This is already the case for 4% or 5%of the chips manufactured worldwide. What is more, the Grenoble area has played and continues to play a central role in development of the new material.

“SOI will gradually replace silicon as the basic material in microelectronics. There is no going back now ”, says Jean-Michel Lamure. Joint founder of Soitec, which claims an 80%share of the world market for SOI, Lamure knows what he is talking about. The firm has just officially opened its second production unit in Bernin, boosting annual production capacity
to more than 2 m wafers. The facility is located just across the road from STMicroelectronics'Crolles 2 fabrication unit, and the R&D centre it operates in partnership with Philips and Motorola.
Crolles 2 is dedicated to the production of 300 mm wafers, the new format that leading chip manufacturers are beginning to use for their most advanced components. In 2002 alone Soitec invested € 85m to ensure that production resources keep pace with demand. Its workforce is expanding too. Currently at 335 it should have increased to 400 by next March.
Soitec started life 10 years ago as an offshoot from Leti-CEA in Grenoble. Its founders were convinced that one day SOI would become a standard material for mass-market components, essential to mobile phones, gaming consoles, automotive power sensors and innumerable other portable devices.
But it has taken a long time to reach that stage. The first industrial applications for SOI appeared at the beginning of the 1980s, in defence and aerospace.
The number one advantage of circuits manufactured on SOI material is that they go on working, even under the most critical conditions, notably radiation and extreme temperatures. This is made possible by a layer of monocrystalline insulating material that protects the circuit itself (increasingly thin and correspondingly sensitive) from interference. But SOI has other advantages, that have become increasingly valuable as microelectronics has evolved. For equivalent consumption SOI chips deliver twice the power.
Philips was, for instance, the first company to use SOI-based components in an audio amplifier. As they require less power, they also produce less heat, of vital importance in large servers.
And of course they give mobile phones greater autonomy, with less need to recharge batteries. All these factors have contributed to the growing success of SOI.
But at the outset not many people were prepared to believe in, less still invest in SOI. “Leti-CEA, in Grenoble, was particularly daring in this respect ”, says Michel Bruel, one of the researchers involved in the project's inception.
He adds:“It devoted substantial resources to R&D in this field, soon obtaining results published in international journals, at a time when all the other research centres were focusing exclusively on transistors ”. Having demonstrated the concept's feasibility, the next challenge was to make the leap to industrial production and cut the cost of manufacturing defect-free monocrystalline material. It was here that the founders of Soitec made a major contribution. When the firm started in 1992, it implemented an ionic implantation process, known as Simox, on the pilot line at Leti.
This process is still used by competitors. Four years later Soitec launched a new manufacturing technology, Smart Cut®, backed by an exclusive Leti patent registered by Michel Bruel. Shin Etsu
Handotai (SEH), of Japan, participated in the funding of the first production unit.
Today, the process is fast becoming the market standard. SEH has just launched its own licensed production source in Japan.
“We are talking to other potential licensees, so that our customers can diversify their sources of supply ”, explains Jean-Michel Lamure.

Jean-Michel Lamure