COMPOSITE SUBSTRATE AND PRODUCTION METHOD

摘要

A composite substrate which includes a silicon layer having less lattice defects is provided. A composite substrate (40) includes an insulating substrate (30) and a functional layer (21) of which one main surface is bonded to an upper surface of the substrate (30). A dopant concentration of the functional layer (21) decreases from the other main surface toward the substrate (30) side in a thickness direction of the functional layer.