Bonded substrate and method for manufacturing bonded substrate

A method for manufacturing a bonded substrate including a copper plate bonded to one or both main surface(s) of a nitride ceramic substrate, the method comprising:

• an application step of spreading a brazing material paste containing Ag, Cu, and Ti to one or both main surface(s) of said nitride ceramic substrate;
• and
• a bonding step of heating and pressurizing said copper plate and said nitride ceramic substrate in vacuum or in an Ar atmosphere in a state in which said copper plate is superposed onto the surface(s) of said nitride ceramic substrate where said brazing material paste has been applied, wherein
• by performing said application step and said bonding step, in said bonded substrate,
• a bonding layer consisting of TiN is generated between said nitride ceramic substrate and said copper plate so as to be adjacent at least to said copper plate, and
• Ag contained in said brazing material paste is diffused in said copper plate to form an Ag distribution region in said copper plate.