CMOS兆赫波感測器和量測系統設計

Abstract

兆赫波是指介於微波和紅外光之間頻段的電磁波，其頻率約在1012Hz附近。近年來兆赫波被發現在天文、地球科學、化學、生醫、物理、國防方面皆有很大的應用價值，由於這頻段一直以來欠缺好的光源以及感測器，應用性有待開發，因此近年來有相當多的研究投入此領域中。 我們嘗試用CMOS 0.18μm製程設計出工作在28.3THz的感測器，會用CMOS的最大原因是CMOS製程的特性為大量生產且便宜。我們設計的感測器為電熱式，感測器的天線將28.3THz的電磁波耦合進來，加熱BJT中的p基體電阻使其溫度升高，再搭配一溫測電路，其輸出電壓會隨著溫度增高而增加。會使用溫測電路的原因為CMOS製程並沒有其他製程的天線耦合輻射熱計所需要的特殊材料。 本論文總共描述了：利用HFSS軟體設計天線、利用ePhysics熱模擬軟體嘗試模擬晶片受到光照射時的溫度分佈、layout及封裝條件、量測系統架設以及量測結果。最後，我們得到兩種不同雷射極化照射下的晶片空間響應圖。

THz wave is the electromagnetic wave whose frequency lies between infrared and microwave. Its frequency is about 1012Hz. Recently, THz wave was discovered having great applications in astrophysics, earth science, chemistry, biomedicine, physics, security. For lacking reliable sources and sensors, the applications in THz wave is not extensively explored, so many research on THz region was conducted recently. We try to design the 28.3THz sensor using CMOS 0.18μm process. The main purpose for choosing the CMOS process is its mass production and cheapness. The sensor we designed is electric-thermal type. The antenna in it couples the 28.3THz electromagnetic wave into the p-island resistor of the BJT and thus heats it up. Then, a thermal sensing circuit is designed to sense the temperature of the BJT. Its output voltage increases with increasing temperature. We use the thermal sensing circuit to replace the special material in antenna coupled bolometer in other process which the CMOS process does not provide. In the thesis, using HFSS to design the antenna, using ePhysics to simulate the temperature distribution of the chip which is illuminated with laser, the package, the measurement system setup, and the measurement result are shown. Finally, we got the spatial response pictures of the chip for two different laser polarizations.