Copper-ceramic substrate with an upper face which can be sintered

A copper-ceramic substrate comprising

• a) a ceramic body and
• b) a copper layer which is connected to the ceramic body in a planar manner, wherein the copper layer has an upper face,
• wherein
• (A) an energy spectrum obtained during analysis of the upper face of the copper layer by X-ray photoelectron spectroscopy
• (i) has at least one signal S1 (t=0 s) which comprises at least one peak P1 (t=0 s) with a maximum in the range of 526 eV-538 eV, wherein the at least one peak P1 (t=0 s) has an area PF1 (t=0 s), wherein the areas PF1 (t=0 s) of all peaks P1 (t=0 s) of the at least one signal S1 (t=0 s) result in a total area GF1 (t=0 s), and
• (ii) has at least one signal S2 (t=0 s) which comprises at least one peak P2 (t=0 s) with a maximum in the range of 0 eV-1400 eV, wherein the at least one peak P2 (t=0 s) has an area PF2 (t=0 s), wherein the areas PF2 (t=0 s) of all peaks P2 (t=0 s) of the at least one signal S2 (t=0 s) result in a total area GF2 (t=0 s),
• wherein the ratio GF1 (t=0 s)/GF2 (t=0 s) has a value V (t=0 s),
• (B) an energy spectrum obtained during analysis of the upper face of the copper layer by X-ray photoelectron spectroscopy after sputtering the upper face of the copper layer for 120 s (sputter gas:
• argon, acceleration voltage:
• 1 kV)
• (i) has at least one signal S1 (t=120 s) which comprises at least one peak P1 (t=120 s) with a maximum in the range of 526 eV-538 eV, wherein the at least one peak has an area PF1 (t=120 s), wherein the areas PF1 (t=120 s) of all peaks P1 (t=120 s) of the at least one signal S1 (t=120 s) result in a total area GF1 (t=120 s), and
• (ii) has at least one signal S2 (t=120 s) which comprises at least one peak P2 (t=120 s) with a maximum in the range of 0 eV-1400 eV, wherein the at least one peak P2 (t=120 s) has an area PF2 (t=120 s), wherein the areas PF2 (t=120 s) of all peaks P2 (t=120 s) of the at least one signal S2 (t=120 s) result in a total area GF2 (t=120 s),
• wherein the ratio GF1 (t=120 s)/GF2 (t=120 s) has a value V (t=120 s), and
• wherein the ratio V (t=120 s)/V (t=0 s) assumes a value in the range of 0.05-0.75.