Method for growing gan compound semiconductor crystal and semiconductor substrate

Abstract

The state of a surface of a substrate or a GaN group compound semiconductor film formed on the substrate is modified with an anti-surfactant material and a GaN group compound semiconductor material is supplied by a vapor phase growth method to form dot structures made of the GaN group compound semiconductor on the surface of the semiconductor film , and the growth is continued until the dot structures join and the surface becomes flat. In this case, the dot structures join while forming a cavity on an anti-surfactant region. A dislocation line extending from the underlayer is blocked by the cavity , and therefore, the dislocation density of an epitaxial film surface can be reduced. As a result, the dislocation density of the GaN group compound semiconductor crystal can be reduced without using a masking material in the epitaxial growth, whereby a high quality epitaxial film can be obtained.