Light‐Absorbing‐Layer‐Free Flash Lamp Annealing for High‐Throughput Fabrication of All‐Solution‐Processed Oxide Electronics

ABSTRACT

Metal oxides exhibit high transparency across the visible spectrum, making them challenging to anneal via flash lamp annealing (FLA). Whether such materials can effectively absorb light and self‐heat remains debated. Conventional workarounds often involve light‐absorbing layers; however, these approaches introduce complexity to the fabrication process and impose limitations on device architecture. Here, we introduce a FLA strategy that enables conversion of metal oxide sol–gels into functional oxides per layer within tens of seconds on both silicon and ultra‐thin glass (UTG) substrates—without additional light‐absorbing layers—by employing a mullite chuck. Finite element analysis (FEA) results indicate that the gel‐to‐oxide transformation is initiated by direct light absorption within the metal oxides. The low thermal conductivity of mullite restricts heat dissipation, facilitating a temperature rise in the metal oxide layers with increasing pulse count and promoting complete conversion. FEA further reveals that metal oxides on UTG attain lower temperatures than those on silicon, due to greater heat dissipation into the UTG substrate. We demonstrate all‐solution‐processed thin‐film transistors and functional logic gates using FLA‐processed metal oxides. This approach shortens fabrication time by two orders of magnitude without sacrificing device performance, highlighting its potential for high‐throughput production of complex integrated circuits.