Fang Zhong, He Yong, Chen Zhequan, Shi Yunlei, Jiao Junjie, Pan Xuchao
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
School of Mechanical Engineering, Zhejiang Industry & Trade Vocational College, Wenzhou 325000, China.
Micromachines (Basel). 2021 Dec 13;12(12):1553. doi: 10.3390/mi12121553.
The micro-bolometer is important in the field of infrared imaging, although improvements in its performance have been limited by traditional materials. SiGe/Si multi-quantum-well materials (SiGe/Si MQWs) are novelty thermal-sensitive materials with a significantly high TCR and a comparably low 1/f noise. The application of such high-performance monocrystalline films in a micro-bolometer has been limited by film integration technology. This paper reports a SiGe/Si MQWs micro-bolometer fabrication with heterogeneous integration. The integration with the SiGe/Si MQWs handle wafer and dummy read-out circuit wafer was achieved based on adhesive wafer bonding. The SiGe/Si MQWs infrared-absorption structure and thermal bridge were calculated and designed. The SiGe/Si MQWs wafer and a 320 × 240 micro-bolometer array of 40 µm pitch L-type pixels were fabricated. The test results for the average absorption efficiency were more than 90% at the wavelength of 8-14 µm. The test pixel was measured to have a thermal capacity of 1.043 × 10 J/K, a thermal conductivity of 1.645 × 10 W/K, and a thermal time constant of 7.25 ms. Furthermore, the total TCR value of the text pixel was measured as 2.91%/K with a bias voltage of 0.3 V. The SiGe/Si MQWs micro-bolometer can be widely applied in commercial fields, especially in early medical diagnosis and biological detection.
微测辐射热计在红外成像领域很重要，尽管其性能的提升受到传统材料的限制。硅锗/硅多量子阱材料（SiGe/Si MQWs）是新型热敏材料，具有显著高的温度系数（TCR）和相对较低的1/f噪声。这种高性能单晶薄膜在微测辐射热计中的应用受到薄膜集成技术的限制。本文报道了一种采用异质集成的SiGe/Si MQWs微测辐射热计制造方法。基于粘结晶圆键合实现了与SiGe/Si MQWs处理晶圆和虚拟读出电路晶圆的集成。对SiGe/Si MQWs红外吸收结构和热桥进行了计算和设计。制造了SiGe/Si MQWs晶圆和一个320×240、像素间距为40 µm的L型像素的微测辐射热计阵列。在8 - 14 µm波长下，平均吸收效率的测试结果超过90%。测试像素的热容量为1.043×10 J/K，热导率为1.645×10 W/K，热时间常数为7.25 ms。此外，在0.3 V偏置电压下，测试像素的总TCR值测量为2.91%/K。SiGe/Si MQWs微测辐射热计可广泛应用于商业领域，特别是在早期医学诊断和生物检测方面。
