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A 55nm Ultra Low Leakage Deeply Depleted Channel Technology Optimized for Energy Minimization in Subthreshold SRAM and Logic

This work presents an Ultra-Low Leakage (ULL) 55nm Deeply Depleted Channel (DDC) process technology for low power Internet of Things (IoT) applications. The DDC ULL devices provide 67% reduction in threshold (VT) variation due to Random Dopant Fluctuation (RDF). Circuit techniques such as subthreshold operation and reverse body biasing (RBB) are codesigned with the technology to maximize the energy/power saving. A test chip implements a 1Kb 6T SRAM, a FIR filter, and a 51-stage RO to showcase how the technology works with circuit techniques to minimize energy. The 6T SRAM array operates reliably down to 200mV with a reduced leakage power of 7nW (85% lower compared to non-DDC devices). The FIR filter consumes just 4.5pJ/cycle operating at 0.36V at 200 KHz.