TECH

French scientists closer to 3nm processors

It has long been no secret that, with 3 nm process technology, transistors will shift from vertical “striated” FinFET channels to horizontal nanopage channels completely surrounded by gates or GAA (gate-all-around). Today, the French CEA-Leti Institute has shown how you can use the manufacturing processes of FinFET transistors to produce multi-level GAA transistors. And maintaining the continuity of technological processes is a reliable basis for rapid transformation.

Seven levels of nanopage channels on a transistor (CEA-Leti)
For the VLSI Technology & Circuits 2020 symposium, experts from CEA-Leti prepared a report on the production of a seven-level GAA transistor (special thanks to the coronavirus pandemic, thanks to which the presentation documents finally began to appear quickly, and not months after the conferences). French researchers have proven that they can produce GAA transistors with channels in the form of an entire “stack” of nanopages using the widely used technology of the so-called RMG process (replacement of the metal gate or, in Russian, replacement of the metal shutter (temporary)). At the same time, the RMG manufacturing process has been adapted for the production of FinFET transistors and, as we can see, it can be extended to the production of GAA transistors with a multilevel arrangement of nanopage channels.


Evolution of the transistor (Samsung)

Samsung, as far as we know, plans to produce two-level GAA transistors with two flat channels (nanopages) located one above the other, surrounded by a gate on all sides, as far as we know the production of 3 nm chips. The experts at CEA-Leti showed that it is possible to produce transistors with seven nanopages of channels and, at the same time, define the channels in the desired width. For example, an experimental seven-channel GAA transistor has been released in versions ranging in width from 15 nm to 85 nm. Of course, this allows defining precise characteristics of the transistors and ensuring their repeatability (reducing the spread of parameters).
According to the French, the more channel levels in a GAA transistor, the greater the effective width of the total channel and, therefore, better controllability of the transistor. Also in the multilayer structure, less leakage currents. For example, a seven-level GAA transistor has leakage currents three times lower than a two-level transistor (conditionally - like the Samsung GAA). Well, the industry has finally found a way, moving away from the horizontal placement of elements in the crystal to the vertical. It seems that microcircuits do not yet need to increase the area of ​​the crystals to become even faster, more powerful and energy efficient.

Source: French CEA-Leti Institute