CNT-count Failure Characteristics of Carbon Nanotube FETs under Process Variations

Carbon Nanotube Field Effect Transistors (CNFET) are promising nano-scaled devices for implementing high performance, very dense and low power circuits. Chemical synthesis and lithography processes are exploited to fabricate CNFETs. Hence, in the presence of sub-wave length lithographic inaccuracies and chemical synthesis imperfections, CNT-count per CNFET deviates and may result in CNFET failure. In this paper, a parameterized model for CNT-count deviation under combined of lithographic and chemical imperfections is presented. The proposed CNT-count model takes advantage of a new CNT density metric which is easily and accurately extractable. We use the proposed model to quantify the impact of process variations on failure probability of CNFETs. Results indicate that the CNFET width variation plays a dominant role in defining the CNT-count failure of CNFETs in addition to CNT density variation.