Organic RFID tags are one of the drivers of flexible electronics research and development. Over the previous years, Holst Centre, imec and TNO, have been successful in reporting state-of-the art results on major conferences, such as ISSCC and IEDM. The current result of a 64-bit transponder circuit at 4.3kb/s shows an improvement of over a factor two compared to the result reported last year at ISSCC. What’s more, results show that chips start to operate at lower voltages (down to 10V), making them more suitable for capacitive and inductive coupling with a readout station.
Main reason behind the increased performance is the use of a dual gate unipolar transistor technology, adapted from rollable-display company Polymer Vision, one of the partners in the Holst Centre research programs. Using a dual gate allows controlling the threshold voltage (Vt) and the thus obtained multiple-Vt technology leads to more robust circuits.
Dual-gate organic TFT (thin-film transistor) circuits have been reported before, but had never surpassed the complexity of basic inverters. Thanks to the tight collaboration within mixed teams of circuit designers and technology developers, Holst Centre, imec and TNO now report 99-stage dual-gate ring oscillators in various topologies, plus 64-bit RFID transponder chips using the same architecture.
Further and ongoing work will demonstrate the viability of the technology towards industrial uptake. Holst Centre therefore gathers leading industrial players from across the value chain around its shared research roadmaps. The work is the result of a close collaboration between TNO and imec teams in Eindhoven and Leuven.