A high-sensitivity compact gas concentration sensor using ultraviolet light absorption with a heating function for a high-precision trimethyl aluminum gas supply system

This work presents a high-sensitivity, real-time, compact gas concentration sensor using a time-sharing dual-wavelength UV light absorption method developed for a high-precision trimethyl aluminum (TMA) gas supply system. We analyzed the characteristics of TMA, examined a method to increase sensitivity by controlling the gas transition, and fabricated a highly reliable heatable gas cell. The detection circuit demonstrated that TMA can be measured stably using a charge amplifier method that can detect various metal organic gases with high sensitivity. By controlling the sensing temperature to increase the ratio of TMA monomers (which have a higher UV absorbance) to dimers, a detection limit of 62.7 ppm was achieved.