Processing‐Induced Performance Limits of Platinum Resistance Temperature Detectors for Reliable Organ‐On‐A‐Chip Sensing

Reliable temperature monitoring remains a critical bottleneck in Organ‐on‐a‐Chip (OoC) systems, where integrated temperature sensors must provide electrical stability, biocompatible encapsulation, and efficient thermal coupling to the biological environment. While the effects of thermal annealing on platinum (Pt) thin films are well established, the influence of fabrication‐related thermal budgets associated with OoC manufacturing has not been systematically correlated with device performance. Here, we establish a direct processing–microstructure–device performance relationship for Pt‐based resistance temperature detectors (RTD). Using Si/Pt and Si/SiO 2 /Pt architectures, we investigate the impact of thermal annealing (up to 900°C) on film morphology and electrical properties and correlate them with device‐level sensing performance. Moderate annealing temperatures (≈300°C), representative of oxide passivation processes, significantly improve electrical performance, reducing resistivity by up to 40% and increasing the temperature coefficient of resistance (TCR) through stress relaxation and grain coarsening. Higher annealing temperatures induce surface roughening and morphological instability, compromising sensor reliability. A SiO 2 interlayer delays degradation and reduces resistivity drift, preserving film integrity under harsh thermal conditions. These results demonstrate that the thermal budget associated with dielectric passivation can be exploited to optimize RTD performance while defining practical processing windows for reliable integration into OoC and other biointegrated microsystems.