Imec demonstrated its latest work on molybdenum disulfide transistors at a semiconductor conference. Transistors based on this so-called 2D material could supersede traditional silicon-based semiconductors.
According to the Imec researchers, the MoS2 transistors show promising properties and the material would lend itself to even smaller transistors than is possible with silicon. In particular, the dimensions of the contact points and the length of the gates could already compete with those of modern finfets with the current experimental specimens. Imec’s fets have contacts of only 13nm and gates of 29 or 30nm. This results in a contact pitch of approximately 50nm. Intel’s 14nm process has a gate pitch of 70nm and an interconnect pitch of 52nm. These measurements are not directly comparable to those of Imec, but they do give an indication.
Thanks to the use of MoS2, of which the imec researchers used a monolayer of about 0.6nm, the channels could be made very short, so that the transistors can be placed closer together. That would mean higher densities of transistors on a chip. The performance of the transistors is certainly not yet at the level of the silicon finfets in terms of control currents, but the potential is certainly there, according to the researchers.
The results of the measurements on the test transistors would agree well with computer models used to predict the properties. This validation would allow the researchers to simulate further improvements first. One of the improvement paths is to make the insulating gate oxide hafnium oxide thinner, and to implement a double instead of a single gate. The results of the imec researchers were presented at IEEE’s International Electron Devices Meeting.