Penn State researchers have created the world’s first CMOS computer based on 2D materials. Made from n-type MoS2 and p-type WSe2 transistors, the 2D-CMOS one-instruction circuit is capable of performing simple logic operations. The chip takes in a supply voltage of < 3 volts and operates at frequencies of up to 25 kilohertz. Power consumption is reported to be minimal at a few picowatts. Switching energy is approximately 100 picojoules for CMOS inversion.
High charge carrier mobility independent of channel thickness makes thin layers of transition metal dichalcogenides (general formula: MX2) prime candidates to succeed silicon in CMOS. Imec has included these materials in its roadmap, tentatively scheduling their introduction in high-volume production by the end of the next decade.
The Penn State team used metal-organic chemical vapor deposition (MOCVD) to grow large sheets of 2D materials and fabricate over 1,000 of each type of transistor. By carefully tuning the device fabrication and post-processing steps, they were able to adjust the threshold voltages of both n- and p-type transistors, enabling the construction of fully functional CMOS logic circuits.
Recent years have seen substantial progress in 2D materials-based electronics, such as wafer-scale growth of 2D materials and fabrication of 2D FETs and circuits. Simple 2D CMOS circuits using exfoliated materials have been reported as well. The Penn State work is the first demonstration of 2D-material integration on a larger scale.
