Research Of Pyroelectric Infrared Detectors Based On Wafer Bonding Technology

Infrared detector is one of the most critical elements for the infrared system. The output infrared radiation signal is converted into voltage signal or current signal based on the principle of infrared detection. This paper summarizes the research status, working principle and the performance requirements for materials of the pyroelectric infrared detector. As an uncooled detector, pyroelectric infrared detector has the following characteristics: 1) it can work at room temperature and has low cost; 2) it can response the infrared radiation for each wavelength; 3) it can detect the radiation as long as the amount of infrared changes. Pyroelectric infrared detector has extensively applications in the fields of military and civilian. In this paper, the pyroelectric infrared detector is studied on both theory and technology and the detector is tested.In theory, the working principle and effect factors on the infrared detector performance, such as material selection and size, are studied. The Lithium niobate chip is selected to design pyroelectric infrared detector. Comparison of the basic principles, main method and process for wafer bonding technology is completed. The bonding method is selected to prepare the detector. In addition, the factors which effect the accuracy of pyroelectric infrared detector are studied, especially the effect of infrared optical gas chamber structure. Three different optical structures, which are side opening, front opening structure, side and front opening, are designed. Performances of the three different structures are tested. Results show that the side and front opening structure has small loss degree and better device stability. Also, the treatments of waterproof, dustproof and anti-static are accomplished owing to the environment with much dust, moisture.In experiment, the key preparation processes (including wafer bonding, thinning, polishing, coating) for pyroelectric infrared detector based on chip bonding technology is studied. Also, the effect factors of different process are analyzed. Comparison of design method for different signal extraction circuits is completed and the negative feedback amplifier is selected. The light response and optical performance characterizations are implemented and the pyroelectric signal is obtained. The effects on the accuracy of detector of optical chamber structure are verified through experiments. The front opening structure is selected and the treatments of waterproof and dustproof are accomplished.In this paper, pyroelectric infrared detector based on wafer bonding technology is developed, which provide theoretical basis, design method and research tool references for infrared detector structure optimization, infrared optical chamber integration and application.