Study Of The Integrated Nano Gas Sensor Arrays Fabricated By Laser Micro-machining And Their Characteristics

Gas sensor arrays were manufactured through the pulsed YAG laser micro machining of Al2O3 plates, pasting technique, and the RuO2 heater and the electrodes integrated onto two sides of plates, respectively. Some important characteristics of the integrated sensor arrays, such as the heating properties, the sensitivity and the repetition of the technique, were investigated. Peculiarly, the effect on the integrated sensors arrays sensitivity and stability by the different thick electrode and sensitive film was studied. The buried RuO2 heater by laser micro machining makes the array have good characteristics, such as the heating properties, the heat response and the temperature distribution on the plate and the sensitivity of the integrated gas sensor arrays. The average power consumption per unit at 400℃, the thermal responsive time and the plane temperature distribution gradient are 500 mW, 20s and 5℃/mm, respectively. The sensitivity of the different arrays is high, stable, and repeatable. The Ag electrodes, which were fabricated through the laser ablation, are stable and uniform. Laser can adjust the space between the electrodes conveniently. The parallel electrode can equably pick up the information of the gas sensing reaction on the parts. Compared with the change of the different thick electrode appearance after the periodic heat impact from room temperature to 400℃, it shows that the stability of the electrode strongly depends on the thickness and uniformity of the electrode film. The dense network or thin film electrode between 7-15μm have better long-term stability. The electrode upper 21μm, which is three dimension multi-slice, has worse stability. The formation mechanism of this property is discussed. Contrasted the sensitivity and the long-term stability of the sensitive film with the different powder size and thickness, and through the mechanism analyzed, the results show that the extreme thin film is not reliable, while the 2, 3 and 4 times thick sensing films are comparatively reliable. Because the thicker the sensing film is, and the stronger the remainder stress becomes, the more rapidly the crack extends, and the shorter the gas sensor natural life is. In the first part of this paper, the gas sensor array and its fabrication in the world had been summarized before the purpose and importance of our research been presented. The second part investigated the fabrication and characteristics of the buried RuO2 heater by laser micro machining, and, the fabrication and reliability of the Ag electrode was researched in the third part. In the fourth part, the fabrication and characteristics of gas sensor array were shown. In the last part, the characteristics and long-term stability of the different thick electrode and sensitive film were discussed.