A 2D microprocessor

Nat. Commun. 8, 14948 (2017)

With silicon electronics pushed to its technological limits the search is well underway for the next generation of semiconductors. Two-dimensional transition-metal dichalcogenides, and molybdenum disulfide (MoS₂) in particular, have been considered as potential successors to silicon. Until now, however, the demonstrations of MoS₂-based electronics have been limited to field-effect transistors, inverters and basic integrated circuits. Now, the technological challenge of realizing complex digital circuits based on MoS₂ has been partially overcome in a recent report by Wachter and colleagues.

The researchers fabricate a one-bit microprocessor measuring 0.6 mm² and comprising 115 bottom-gated transistors with a chemical vapour deposition-grown MoS₂ bilayer as a channel. Each transistor is characterized by an average field-effect mobility of 3 cm² V⁻¹ s⁻¹ and an on/off ratio of 10⁸. Despite the minimal transistor count the circuit contains all essential subunits to perform basic arithmetic and logical operations and can be potentially scaled to multi-bit data. By running an example program, Wachter et al. obtain good signal integrity and rail-to-rail performance of the microprocessor. The feasibility of the presented electronic platform is currently limited by the overall device yield, which remains low due to the non-uniformity of the MoS₂ films and other defects introduced during the transfer procedure to prepare the microprocessor.