SiGe/Si Multi-Quantum Wells Film Materials Testing System

Bolometer is one of the third generation uncooled infrared detector based on MEMS technology, and it has a very broad prospects in the field of civil and military. The infrared-sensitive film materials is the most important element in bolometer, and the film materials’TCR is important indicator, which directly determines the performance of bolometer. TCR also has relationship with lots of bolometer performance indicators such as responsivity, NETD and so on. On the one hand, film materials’TCR test result can evaluate thermal property of SiGe/Si multi-quantum wells infrared-sensitive pixel which has micro-bridge structure. On the other hand, the test result provides guidance in preparation processes of SiGe/Si multi-quantum wells infrared-sensitive film materials.According to the SiGe/Si multi-quantum wells pixel structure, film materials properties and working principle, this paper have designed SiGe/Si multi-quantum wells infrared-sensitive film materials testing system, which is used to test film materials’TCR. This paper also analyze heat capacity and thermal conductivity of multi-quantum wells film materials, then evaluates its thermal property.At first, this paper discuss the overall design scheme of testing system through analyzing the working principle of SiGe/Si multi-quantum wells pixel in vacuum environment.According to the general design scheme, the testing system circuits design is divided into three parts:Film array driver circuits design, Film array signal acquisition circuits design and Lab VIEW testing system software design.Finally, the measuring accuracy of testing system can reach1%, which can meet TCR test requirements. Secondly, we test SiGe/Si multi-quantum wells film materials samples, which TCR is up to2.24%/℃on average. Then we analyze thermal conductivity and heat capacity of samples, as well as evaluate the thermal property of the SiGe/Si multi-quantum wells film samples.