Crystal firm, crystal substrate, and semiconductor device

摘要

A crystal foundation having dislocations is used to obtain a crystal film of low dislocation density, a crystal substrate, and a semiconductor device. One side of a growth substrate ( 11 ) is provided with a crystal layer ( 13 ) with a buffer layer ( 12 ) in between. The crystal layer ( 13 ) has spaces ( 13 a), ( 13 b) in an end of each threading dislocation D₁ elongating from below. The threading dislocation D₁ is separated from the upper layer by the spaces ( 13 a), ( 13 b), so that each threading dislocation D₁ is blocked from propagating to the upper layer. When the displacement of the threading dislocation D₁ expressed by Burgers vector is preserved to develop another dislocation, the spaces ( 13 a), ( 13 b) vary the direction of its displacement. As a result, the upper layer above the spaces ( 13 a), ( 13 b) turns crystalline with a low dislocation density.