This work firstly demonstrates an ultra-low leakage microcontroller unit (MCU) based on 55nm tunnel FET (TFET) -CMOS hybrid 300mm foundry platform. By utilizing the large I ON and record high I ON /I OFF ratio of the dopant segregation TFET (DS-TFET), a 1Kbit TFET-Gated-Ground static random access memory (TGG-SRAM) is implemented in MCU always-on domain. A voltage-stacking scheme is proposed to regulate the supply voltage. Experimental results show that TGG-SRAM and TFET-MCU obtain order of magnitude standby power reduction, cost 6nA (data retention) and 75nA (deep-sleep mode) leakage current respectively, indicating the great potential of the TFET-CMOS hybrid platform for cutting-edge power-dieting MCU.