Performance and stability optimization of SiN/Ag/SiN Transparent Electrodes Deposited by HiPIMS on PET substrates for Flexible Electronics

• Transparent SiN/Ag/SiN trilayers electrodes deposited on PET substrates via HiPIMS. • Achieves 94 % transmittance, 9 Ω/sq sheet resistance, and high bending stability. • Optimized structure exhibits long-term stability, thermal and mechanical reliability. • The structures are suitable for applications in wearable and flexible electronics. Flexible, highly transparent and conductive SiN/Ag/SiN multilayer structures were fabricated on PET substrates using high-power impulse magnetron sputtering (HiPIMS), providing a novel and promising alternative to conventional ITO electrodes for flexible electronics. The effect of individual layer thicknesses on optical, electrical, and mechanical properties was systematically investigated. The optimized structure, SiN(37 nm)/Ag(10 nm)/SiN(37 nm), shows excellent performance with high transmittance (94 %@550 nm), low sheet resistance (9 Ω/□), and a high figure of merit (FoM₅₅₀ = 62.76 × 10⁻³ Ω⁻¹). GIXRD and cross-sectional SEM confirmed the continuity and crystallinity of the ultrathin Ag layer, while Hall measurements revealed high carrier mobility and charge density. The top SiN layer influences optical interference and surface plasmon resonance, enabling tunable spectral behavior, while the bottom dielectric layer improves adhesion and provides a diffusion barrier between the Ag and the PET substrate. Real-world viability is assessed through tests under varying temperature, aging, and bending cycles. Results show that thinner Ag layers (5 nm) electrically degraded over time, while thicker SiN layers (60 nm) reduced mechanical flexibility. The SiN 37 /Ag 10 /SiN 37 multilayer maintained structural integrity and optoelectronic performance under mechanical and environmental stress, demonstrating long-term stability. These findings highlight NMN electrodes as strong candidates for wearable devices, flexible displays, and optoelectronic applications.