Integration of a Passive-Type UHF RFID Tag Using Ferroelectric Memory Technology

Abstract

We investigated a passive-type rewritable radio-frequency identification (RFID) tag operating at the UHF (860 – 960 MHz) band and using ferroelectric memory (FeRAM) technology. The transponder integrated circuit(IC) for the UHF RFID tag was implemented with 0.25-μm one-poly four-metal standard logic CMOS technology with the addition of a FeRAM and Schottky diodes. The Pb(Zr,Ti)O3(PZT) capacitor array with a unit area of 1.4 × 1.4 μm for the FeRAM-embedded RFID tag showed a remnant polarization of 30 μC/cm and a leakage current of 1 × 10−5 A/cm at 3 V after full process integration. The novel ferroelectric technology utilizing a stacked capacitor structure and a high capacitance PZT capacitor allowed a highly competitive transponder chip size (550 × 550 μm) by reducing the area of the analogue circuit without adding any complexity to the process integration. The PZT capacitor-based analogue circuitry showed almost the same performance as that of conventional capacitor type circuitry. Thus, the ferroelectric memory technology is very promising for the realization of a cost-effective, passive-type, rewritable UHF RFID tag.