The Study On Thermal Devices Of Un-cooling Bi-material Micro-cantilever Array

Objects in dark environment can not be seen by human eyes. This problem can be solved successfully by thermal detectors which have very important application value in many fields, such as military and civilian. In recent years, one of the important detectors is thermal detector, which is based on bi-material micro-cantilever focal plane array and optical readout.The thermal detection system, which is based on bi-material and optical readout structure, is raised in this paper. This system is read out in the optical way that helps reduce the structure cost largely and make the manufacture process more efficient. The properties of Si3N4films and parameters in different process are researched. The results are shown as follows.1) Thermal detector is designed:Glass is the substrate. The structure array is the scale of120X120array and device unit size is40μm X40μm. Other structure design parameters are aimed to simplify detection structure and make the reflection panel as large as possible to get better infrared radiation absorption.2) Research on thermal absorption panel Si3N4film: The Si3N4film will be affected by several PECVD parameters such as rf power, reaction gas ratio, reaction pressure and working temperature. By adjusting the process parameters, such as PECVD rf power, reaction pressure, deposition time, and working temperature, when the thickness of the film is500nm, the relative absorption is3.5and the tensile stress is426MPa. The Si3N4film will be affected by several ICP parameters, such as power, bias power, gas component and gas flow, the etching rate of Si3N4can reach to336nm/min with Si3N4/EPG533selection ratio of2.05.3) Research on the manufacturing process of device: The photoetching machine is used to obtain different images, spin-coating is used to even glue, magnetron sputtering is used to get Au film, ICP and PECVD are used to obtain absorption panel. Each layer is patterned in using the lithography. The optimized parameters are as follows:the speed of spin-coating is3000r/min, and the sputtering power is200W, and the argon flow is80mL/min, and the pressure is2.0Pa during magnetron sputtering. Temperature is35O℃, and the power is100W, and the pressure is70Pa, the SiH4flow is40mL/min and N2flow is60mL/min. The ICP power is250W, the self-bias is50W.