Nanolaminated HfO₂/Al₂O₃ Dielectrics for High‐Performance Silicon Nanomembrane Based Field‐Effect Transistors on Biodegradable Substrates

Abstract Emerging transient electronics offer great potential in eco‐friendly and bioresorbable electronic applications. In this study, bendable and biodegradable metal‐oxide‐semiconductor field‐effect transistors (MOSFETs) and metal‐oxide‐semiconductor capacitors (MOSCAPs) have been fabricated by integrating HfO₂/Al₂O₃ high‐k bilayers on the transferred silicon nanomembranes (Si NMs) and utilizing PLGA‐gelatin‐chitosan polymeric substrates. The transient n‐channel MOSFETs demonstrate high effective mobility of 871 cm² V⁻¹ s⁻¹, high on‐state current of 27.6 µA µm⁻¹, high on/off current ratio > 10⁷, and low gate leakage current ≤2.7 × 10⁻⁷ A cm⁻². The accumulation capacitance of the transient MOSCAPs exceeds 6.5 × 10⁻⁷ F cm⁻², indicating an enhanced gate control over the Si NM channel. The presented excellent performance is on par with the highest performance of the reported transient devices. Accelerated soaking tests in aqueous environments combined with systematic studies of the electrical characteristics as a function of the transience stage reveal the dissolution chemistry and kinetics of the biodegradable devices associated with the underlying transient behaviors. Moreover, detailed analysis of mechanics provides insights into the optimized device‐grade geometries for precise control of the functional lifetimes. These results will be beneficial to paving a realistic path for achieving high‐performance and on‐demand water‐soluble Si NM based MOSFETs toward futuristic applications in disposable electronics and temporary biomedical implants.