Inverted metamorphic multijunction solar cells having a permanent supporting substrate

A method of manufacturing a solar cell comprising:

• providing a semiconductor growth substrate;
• depositing on said growth substrate a sequence of layers of semiconductor material forming a solar cell, including a first solar subcell deposited on said substrate having a first band gap;
• a second solar subcell deposited over said first subcell having a second band gap smaller than said first band gap;
• a grading interlayer deposited over said second subcell composed of InGaAlAs and having a third band gap larger than said second band gap;
• a third solar subcell deposited over the grading interlayer and having a fourth band gap smaller than said second band gap such that said third subcell is lattice mismatched with respect to said second subcell;
• depositing a metal contact layer over said sequence of layers;
• depositing a coating layer over the metal contact layer;
• providing a permanent support substrate;
• bonding an adhesive polymer layer to one surface of the permanent support substrate at a curing temperature above 350° C.;
• affixing the cured adhesive surface of a permanent supporting substrate directly over said metal contact layer;
• permanently bonding the supporting substrate to the metal contact layer by a thermocompressive technique;
• and
• removing the growth substrate.