The Research Of Wind Speed And Wind Direction Array Two-parameter Sensor Based On Pt Film

Wind sensors are wildly used in many fields. High sensitive, cheap, portable wind sensors are often needed. In this thesis, on the base of MEMS technique and thin film technique, a novel wind speed and direction two-parameter sensor is presented.Two-parameter anemometer is designed based on the theory of thermal difference in temperature. When the surface of the sensor is heated, the temperature of chip is higher than the temperature of ambience. When wind blows the surface of the sensor, the surface can be cooled asymmetrically. So the surface of sensor can come into being temperature grads along the wind direction. By measuring the signal of the difference in temperature of the two hot sensitive resistances in vertical direction, we can obtain the information of wind speed and wind direction at the same time.The physical chemistry performance of platinum is steady. At present platinum is the best material for making thermal resistances. Its steady repeatable character can be 10-4K, and it is the best in repeatable character. It can be used as sensitive material of standard temperature sensor in the temperature area of -259.34℃-630℃. Platinum thin film thermal resistances array of the sensor are deposited on substrate of ceram using high pure platinum target, using direct current magnetron sputtering technology, in argon setting. The chip of sensor is made up of five array elements on the surface which is sensitive to temperature and four array elements on the surface which is used to heat chip.The main contents can be summarized as follows: (1)The figure of the sensor is designed, the process flow and the testing method of the sensor, are established. (2)The influence on platinum film of the choice of substrate, the purification of substrate, the temperature of substrate, the quality of target material, deposition rate and so on, and the influence on deposition rate, film surface of sputtering power are studied. (3) The effect of the parameters such as magnetron sputtering power and time of magnetron sputtering on fabrication of platinum thin film is studied. The relations between sputtering power, sputtering time and the thickness of platinum film are analyzed. It is suggested that in the case of the same sputtering power, the thickness of the film increases linearly along with the rise of sputtering time; in the case of the same sputtering time, the thickness of the film also increases along with the rise of sputtering power. The three dimension model of sputtering time, sputtering power and the thickness of film is set up by Matlab software. (4) Via analyzing the microstructure of the platinum thin film by SEM (scanning electron microscope), controlling processing parameter is established. (5) When heating voltage and wind direction are fixed, the relation of Pt film array elements which is sensitive to temperature and wind speed is analyzed, and the graph is set up. The graph of the alteration of Pt film array elements which is sensitive to temperature along with heating voltage is set up. (6) The mechanism of platinum film forming, the operating and detection principle of sensor are expounded. The principle model and mathematics relational expression of sensor and are set up.