Ppb-level HF sensor in GeF4 gas matrices with a 76 m TDLAS cell

The detection of trace hydrogen fluoride (HF) impurities in germanium tetrafluoride (GeF₄) is to maintaining the purity and safety standards required in semiconductor manufacturing and nuclear industry. Currently, few studies have measured HF concentrations, and none have addressed its detection as an impurity in high-purity GeF4. We present here a highly sensitive gas sensor based on tunable diode laser absorption spectroscopy (TDLAS) for HF monitoring in GeF₄ matrices. The system employs a distributed feedback diode laser operating at 1.278 μm, targeting the HF first-overtone absorption line, and an optimized White cell having a 345 mm length cavity and providing an effective optical path length of 76 m. Wavelength modulation spectroscopy was employed and the sensor response was validated using HF samples at varying concentrations, achieving excellent linearity with R² > 0.999. The minimum detection limit was determined to be 48 ppb (3σ), highlighting superior sensitivity among near-infrared HF detection approaches. These results highlight the system’s strong potential for high-purity gas analysis and real-time process control in semiconductor environments.