Efficient metallic carbon nanotube removal for highly-scaled technologies

While carbon nanotube (CNT) field-effect transistors (CNFETs) promise to improve the performance and energy efficiency of digital systems beyond the limitations of silicon CMOS, the presence of metallic CNTs (m-CNTs) remains a major challenge. Existing techniques for removing m-CNTs are inadequate, as they face one or more of the following scalability challenges: scaling to large circuits (≥99.99% of m-CNTs must be removed without inadvertently removing semiconducting CNTs, s-CNTs), scaling to short channel lengths (for highly-scaled contacted gate pitch (CPP)), and scaling to small inter-CNT spacing (for high CNT densities required for high CNFET I_ON). We demonstrate a new m-CNT removal technique that, for the first time, overcomes all of these scalability challenges, as it: (a) removes ≥99.99% of m-CNTs vs. ≤1% of s-CNTs, (b) scales to any arbitrary CPP, and (c) scales to high CNT densities (≥200 CNTs/μm).