Interface roughness in Resonant Tunnelling Diodes for physically unclonable functions
Pranav Acharya, Vihar Georgiev · Solid-State Electronics · 2025
Resonant Tunnelling Diodes with Interface Roughness (IR) were investigated for their potential as components of Physically Uncloneable Functions (PUFs). A comparison of an RTD with IR against a ‘smooth’ device without IR, showed a reduction in current and Peak to Valley Current Ratio (PVCR) between the resonant peak and valley currents I r / I v . Furthermore, IR resulted in a perturbation of the Negative Differential Region (NDR) of the IV characteristic to higher bias. This perturbation was due to IR effectively thickening barriers and thereby narrowing the Quantum Well (QW) and leading to a higher ground state QW energy. Variation of correlation length L C and roughness asperity Δ R M S for batches of 25 randomly generated RTDs with IR showed that increasing Δ R M S decreased mean PVCR and increased the standard deviation of the resonant peak voltage V r and current I r . 150 RTDs with an L C of 7.5 nm and Δ R M S of 0.3 nm resulted in a min-entropy of 1.275 bits, showing that 100 RTDs could idealistically compose a PUF encoding 127 bits.