An Inkjet-Printed Inverter Array Realizing a Physically Unclonable Function

In this work, we integrate printed inverters into array structures to form hardware security primitives, such as physically unclonable functions. We use inkjet-printed electrolytegated transistors as active devices and PEDOT:PSS as a crossover conductive layer in addition to sputtered ITO resistors and interconnects. Our array-integrated inverters incorporate shared-supply voltage, -ground and -gate lines. The design exploits variations of the printed inverter transfer curves. The circuit can be used to generate a 36-bit wide unique response at $V_{\text{in}}=0.5\mathrm{V}$ and is easily scalable to higher bit width. By using multiple input voltages, the challenge response pair schedule can be enlarged, which leads to either an increased challenge response pair space or increased bit width.