The Resistor Array Infrared Scene Generator Simulation Design And Microfabrication Process

Dynamic infrared scene projector (DIRSP) is the key component of the hardware-in-the-loop (HWIL) simulation system. The resistor arrays based on electrical heated microemitter possess the advantages of low power dissipation, wide temperature band, high resolution and high fill factor, and have become the most promising technology for IR projection. The pixel thermal-isolate structure design and the device micromachining processes are the core issues of the resistor array DIRSP devices.In this thesis, the pixel thermal-isolate structure was designed and optimized as to meet the main requirements of DIRSP, and the micromachining processes have been explored. The conclusions are as follow:1.Optimum pixel structure was achieved using the finite element analysis software-ANSYS. A thin film resistor array model based on polyimide (PI) thermal-isolate layer was build up. By performing design optimization of the model under ANSYS environment, we get the optimum thickness of the PI layer is 3μm. The simulation results of the optimized model show that the optimum structure has a crosstalk smaller than 10% between neighboring pixels, and a 0.5ms rise time and 1ms fall time of pixel surface temperature, while applying 100mW power to a pixel. The array frame rate can achieve 500Hz.2.The preparation and wet etching process of PI film were optimized. It was found that the PI film quality can be improved using substrate pretreatment process; The thickness of PI layer depends upon the viscosity of PAA and the spin speed of coating; The PI pattern quality is affected by the PI precuring process and the etchant concentration. By using the optimized preparation and wet etching process of PI, desirable PI thermal-isolate pattern with 3μm were fabricated on (100) Si substrates.3.A 2×16 thin film resistor array for infrared scene projection was fabricated under micromachining technologies. The sheet resistance of NiCr film which is the microemitter material was controlled to be 200?/□by optimizing sputtering process. A 2×16 resistor array including three kinds of pixel resistance of 5k?, 10k?, and 20k? was fabricated. The array has a pixel size of 170μm×170μm, and a 20μm wide trench between neighboring pixels.4.Device testing was conducted using a FLUKE T50 IR thermal imager. The results show that the pixel surface apparent temperature can achieve 400K with relatively low power consumption of 300mW. The resistor arrays can meet the requirements of MWIR and LWIR hardware-in-the-loop simulation.