[19a-B201-1~8] 3.15 Silicon photonics

△ [19a-B201-6] Threading Dislocation Density Reduction in Selectively Grown Inverted-rib Ge on Si

〇(DC)Motoki Yako¹, Yasuhiko Ishikawa², Kazumi Wada^1,3 (1.Univ. of Tokyo, 2.Toyohashi Univ. of Tech., 3.Massachusetts Inst. of Tech.)

Keywords:Germanium, Epitaxial Growth, Threading Dislocation Density

A novel threading dislocation density (TDD) reduction model is proposed and demonstrated to reduce the TDD in Ge on Si substrates. The TDD reduction model is based on three fundamental phenomena: the bending of dislocations due to image force, controlling cross section of selective epitaxial growth (SEG) Ge by growth temperature, and the behavior of SEG Ge to become flat layer after coalescence. TDD as low as 4×10⁷ cm^-2 was realized in 1-µm-thick Ge layers without any high temperature annealing nor thick buffer layer. The experimentally obtained TDD well reproduces the calculation results based on the TDD reduction model.