Why Can Smart Cut® Change the Future of Microelectronics?

Abstract

Deposition techniques like chemical vapor deposition (CVD) offer to the semiconductor industry the initial flexibility to deposit thin films of key materials on many kinds of substrates. The homoepitaxy or heteroepitaxy techniques using CVD or molecular beam epitaxy (MBE) add the flexibility to get a pure monocrystalline thin film but with a major limitation: the starting substrate has to be monocrystalline. The missing technology has always been the one which allows the growth of a thin monocrystalline film on any kind of substrate. Hydrogen induced splitting (known today as Smart Cut®), discovered at the LETI laboratory in 1991, provides a unique opportunity to get crystalline layers on any kind of substrate. Therefore, a new tool is offered to the semiconductor industry, for new material developments and new structures. This technique is in use in production today on a first application: silicon-on-insulator (SOI) wafers which consist of a monocrystalline film of silicon on a thin amorphous silicon dioxide layer, on top of a silicon wafer. We will discuss the SOI application of the Smart Cut® technology and present other recently demonstrated breakthroughs in new material development, including SiC, compound semiconductor or 3D structures.

Fabrication and characterization of silicon-on-insulator wafers

“…The Smart Cut ™ technology enables unparalleled precision in controlling the thickness of the transferred silicon layer on the handle wafer, which can be controlled based on the energy of ion implantation. Additionally, by manipulating the oxidation time and polishing steps, the thickness of both the device layer and the BOX layer can be varied across a broad spectrum with high uniformity [37]. This technology permits the device layer thickness to range from as little as 4 nm to as much as 1.5 µ m, and the BOX layer thickness can vary from 5 nm up to 5 µ m [29,38,39].…”