Composite substrate, manufacturing method thereof and semiconductor device

A semiconductor device, comprising:

• a composite substrate, wherein the composite substrate comprises:
• a supporting substrate layer;
• a buried layer patterned on the supporting substrate layer, the buried layer being provided with a plurality of grooves arranged at intervals and at least partially penetrating the buried layer;
• and
• a growth substrate layer on the buried layer,
• wherein the supporting substrate layer comprises a plurality of charge trapping regions respectively beneath the plurality of grooves, and a shape of a projection, on a plane parallel to the supporting substrate layer, of each charge trapping region at least partially overlaps a shape of a projection, on the plane, of a respective groove;
• and
• the supporting substrate layer further comprises a substrate structure region enclosing the charge trapping region, a conductivity type of the substrate structure region is an n type or a p type, and a conductivity type of the charge trapping region is opposite to that of the substrate structure region.

A method for manufacturing a composite substrate, comprising the steps of:

• S1:
• providing a supporting substrate layer;
• S2:
• forming a buried layer on the supporting substrate layer;
• S3:
• etching to pattern the buried layer to form a plurality of grooves arranged at intervals and at least partially penetrating the buried layer;
• S4:
• forming a plurality of charge trapping regions, respectively beneath the plurality of grooves, in the supporting substrate layer, a shape of a projection, on a plane parallel to the supporting substrate layer, of each charge trapping region at least partially overlapping a shape of a projection, on the plane, of a respective groove;
• and
• S5:
• bonding a growth substrate layer on a side, away from the supporting substrate layer, of the buried layer,
• wherein the supporting substrate layer further comprises a substrate structure region enclosing the charge trapping region, a conductivity type of the substrate structure region is an n type or a p type, and a conductivity type of the charge trapping region is opposite to that of the substrate structure region.