[19p-P10-1~6] 15.5 Group IV crystals and alloys

▲ [19p-P10-4] Formation of c-SiGe graded layer on c-Si substrate by thermal treatment

〇(M1C)NORRASHIDAH RASHID¹, Tetsuya Kaneko¹, Masao Isomura¹ (1.Tokai Univ.)

Keywords:Graded layer, SiGe, Si substrate

Crystalline silicon-germanium (c-SiGe) films have been investigated as a narrow-bandgap material. The bandgap of c-SiGe can be controlled by changing the concentration ratio of Si and Ge. Because of that, we pursue to develop c-SiGe solar cells as bottom cells of Si-based stacking solar cells to utilize more infrared light. However, the difference of lattice constants between c-Si and c-SiGe causes defects at the interface of the two layers. In this experiment, we have investigated the graded concentration layer to adjust the lattice constant. High temperature thermal treatment has been conducted on germanium (Ge) thin film on silicon substrate (Si-sub) to achieve the graded layer with the thermal diffusion of c-Ge.