Patent ID: 7932164

Claim:
A method for manufacturing a semiconductor substrate comprising the steps of: irradiating a surface of each of first and second to n-th (n≧3) single crystal semiconductor substrates with ions to form an embrittlement layer at a predetermined depth from the surface of each of the first and second to n-th single crystal semiconductor substrates; bonding each of the first and second to n-th single crystal semiconductor substrates to a base substrate, with an insulating layer provided over at least one of each of the first and second to n-th single crystal semiconductor substrates and the base substrate, interposed between each of the first and second to n-th single crystal semiconductor substrates and the base substrate; separating each of the first and second to n-th single crystal semiconductor substrates along the embrittlement layer by heat treatment to fix each of first and second to n-th single crystal semiconductor layers over the base substrate; irradiating a plurality of regions of the first single crystal semiconductor layer with a plurality of laser lights having energy densities different from one another, each of the energy densities being specific to one of the plurality of regions; measuring carbon concentration distribution and hydrogen concentration distribution in a depth direction of each of the plurality of regions of the first single crystal semiconductor layer after irradiating with the plurality of laser lights; and irradiating the second to n-th single crystal semiconductor layers with laser light under a condition of energy density where a local maximum of a carbon concentration is observed and a shoulder peak of a hydrogen concentration is observed in concentration distribution in a depth direction of the first single crystal semiconductor layer.