Composite substrate, laminate, method for producing composite substrate, and method for producing laminate

A composite substrate for graphene film production, the composite substrate comprising:

• a substrate having a thermal expansion coefficient of 2.0×10−6 (K−1) or less;
• an oxide film;
• and
• a metal film containing Cu or Ni, in this order, wherein
• the composite substrate satisfies the following requirement 1 or requirement 2:
• requirement 1:
• the metal film contains Cu, a diffraction peak 1A derived from either a (111) plane or a (100) plane is observed by XRD measurement for the metal film by a θ-2θ method, and in a chart obtained by the XRD measurement, a diffraction peak derived from a lattice plane of a Cu crystal other than the diffraction peak 1A is not observed, or an intensity of any diffraction peak derived from the lattice plane of the Cu crystal other than the diffraction peak 1A is 1/10 or less of an intensity of the diffraction peak 1A, and
• requirement 2:
• the metal film contains Ni, a diffraction peak 2A derived from a (111) plane is observed by a XRD measurement for the metal film by a θ-2θ method, and in a chart obtained by the XRD measurement, a diffraction peak derived from a lattice plane of a Ni crystal other than the diffraction peak 2A is not observed, or an intensity of any diffraction peak derived from the lattice plane of the Ni crystal other than the diffraction peak 2A is 1/10 or less of an intensity of the diffraction peak 2A.