Stack-shaped multiple solar cell (MS), comprising - a first part cell (TZ1) having an upper side and a lower side and second part cell (TZ2), wherein the first part cell (TZ1) is formed as uppermost part cell so that incident light (L) is incident firstly on the upper side of the first part cell (TZ1) and thereafter via the lower side on the second part cell (TZ2), - a first tunnel diode (TD1) arranged between the lower side of the first part cell (TZ1) and the second part cell (TZ2), - a window layer (FS1), wherein the window layer is arranged on the upper side of the first part cell (TZ1) and the band gap of the window layer (FS1) is greater than the band gap of the first part cell (TZ1), - at least two metal fingers (M1) spaced from one another, wherein a cover layer (AB) is arranged below the metal fingers (M1) and above the window layer (FS1), an additional layer (FS2) is arranged below the cover layer (AB) and above the window layer (FS1), wherein the thickness of the additional layer (FS2) is less than the thickness of the window layer (FS1) and the band gap of the additional layer (FS2) is smaller than the band gap of the window layer (FS1) and - the window layer (FS1) and the additional layer (FS2) comprise the same elements, but in a different stoichiometry, characterised in that - the thickness of the additional layer (FS2) between the metal fingers (M1) is less than below the metal fingers (M1), - the window layer (FS1) and the additional layer (FS2) each comprise a compound with at least the elements In, Al, P or consist of InAlP and the additional layer (FS2) has a higher In concentration and a lower Al concentration by comparison with the window layer (FS1). - a first part cell (TZ1) having an upper side and a lower side and second part cell (TZ2), wherein the first part cell (TZ1) is formed as uppermost part cell so that incident light (L) is incident firstly on the upper side of the first part cell (TZ1) and thereafter via the lower side on the second part cell (TZ2), - a first tunnel diode (TD1) arranged between the lower side of the first part cell (TZ1) and the second part cell (TZ2), - a window layer (FS1), wherein the window layer is arranged on the upper side of the first part cell (TZ1) and the band gap of the window layer (FS1) is greater than the band gap of the first part cell (TZ1), - at least two metal fingers (M1) spaced from one another, wherein a cover layer (AB) is arranged below the metal fingers (M1) and above the window layer (FS1), an additional layer (FS2) is arranged below the cover layer (AB) and above the window layer (FS1), wherein the thickness of the additional layer (FS2) is less than the thickness of the window layer (FS1) and the band gap of the additional layer (FS2) is smaller than the band gap of the window layer (FS1) and - the window layer (FS1) and the additional layer (FS2) comprise the same elements, but in a different stoichiometry, - the window layer (FS1) and the additional layer (FS2) comprise the same elements, but in a different stoichiometry, characterised in that - the thickness of the additional layer (FS2) between the metal fingers (M1) is less than below the metal fingers (M1), - the window layer (FS1) and the additional layer (FS2) each comprise a compound with at least the elements In, Al, P or consist of InAlP and the additional layer (FS2) has a higher In concentration and a lower Al concentration by comparison with the window layer (FS1). - the thickness of the additional layer (FS2) between the metal fingers (M1) is less than below the metal fingers (M1), - the window layer (FS1) and the additional layer (FS2) each comprise a compound with at least the elements In, Al, P or consist of InAlP and the additional layer (FS2) has a higher In concentration and a lower Al concentration by comparison with the window layer (FS1). <EOS>