Al-Doped Silicon-Based Thin Film Humidity Sensors Prepared via Metal Induced Method

The authors report the resistive humidity sensors of Si-based thin film prepared by Al induced method on the glass substrates. Sensors were fabricated at annealing temperature of 500°C and time of 5, 45 and 90 minutes respectively. Experimental results indicate that the amorphous silicon (a-Si) thin film grow into crystal silicon (c-Si) with increasing annealing time. By measuring current-voltage characteristics of samples at 50°C show that the largest relative humidity (RH) ratio of 80% and 30% was obtained of the a-Si sample. For a-Si sample, it was found that current of sample increased from 7 × 10−10 to 1.3 × 10−7 A as we increased the temperature from 25°C to 80°C with 5 V applied bias and 80% RH. It was also found that measured current were 2.05 × 10−10, 4.67 × 10−9, 14.03 × 10−9, and 16.28 × 10−9 A when measured with 30, 50, 70 and 80%-RH, respectively.