Jump test for metallic CNTs in CNFET-based SRAM

SRAMs built on Carbon Nanotube Field Transistors (CNFET) are promising alternatives to conventional CMOS-based SRAMs, due to their advantages in terms of both power consumption and noise margin. However, non-ideal Carbon Nanotube (CNT) fabrication process generates metallic-CNTs (m-CNTs) along with semiconductor-CNTs (s-CNTs), rendering correlated faulty cells along the growth direction of the m-CNTs. Based on this phenomenon, we propose a novel testing algorithm for detecting m-CNTs, wherein consecutive write and read operations jump over multiple cells rather than marching through each and every cell, thereby significantly reducing the testing cost. The proposed jump test can be invoked before the march test to screen out those CNFET-SRAMs doomed to failure, and this can reduce the subsequent test overhead. Experimental results show that the proposed solution is able to achieve a high fault coverage with much less testing cost.