Post Annealing Effects on the Electrical Properties of Polysilicon Metal-Semiconductor-Metal Photodetectors

This study investigated the effects of the post annealing temperatures on the electrical and interfacial properties of a metal-semiconductor-metal photodetector(MSM-PD) device. The interdigitate type MSM-PD devices had the structure Al(500 nm) / Ti(200 nm) / poly-Si(500 nm). Structural analyses of the MSM-PD devices were performed by employing X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). Electrical characteristics of the MSM-PD were also examined using current-voltage(I-V) measurements. The optimal post annealing condition for the Schottky contact of MSM-PD devices are $350^{\circ}C$-30minutes. However, as the annealing temperature and time are increased, electrical characteristics of MSM-PD device are degraded. Especially, for the annealing conditions of $400^{\circ}C$-180minutes and $500^{\circ}C$-30minutes, the I-V measurement itself was impossible. These results are closely related to the solid phase reactions at the interface of MSM-PD device, which result in the formation of intermetallic compounds such as $Al_3Ti$ and $Ti_7Al_5Si_{12}$.

폴리 실리콘을 이용한 금속-반도체-금속 광 검출기의 열처리에 따른 전기적 특성