NOVELTY - The method involves forming a semiconductor contact layer (104) composed of gallium arsenide over a top subcell. A metal contact layer (123) including a germanium layer and a palladium layer, is deposited over the semiconductor contact layer. An ohmic metal contact is formed from the metal contact layer to the semiconductor contact layer at temperature of 210 degree Celsius, where thickness of the palladium layer is 50 nm and thickness of the germanium layer is 100 nm.    USE - Method for forming a multi-junction solar cell i.e. photovoltaic cell, utilized as an energy source for commercial and consumer-oriented application. Can also be used for transistor, thermophotovoltaic cell, photodetector and LED.    ADVANTAGE - The method enables using surfactants to reduce threading dislocations in the active regions, thus improving overall solar cell efficiency.    DETAILED DESCRIPTION - The metal contact layer comprises a sequence of layers selected from a group consisting of palladium/germanium/titanium/palladium, palladium/germanium/gold, palladium/germanium/silver, palladium/germanium/platinum/silver, palladium/germanium/platinum/silver, palladium/germanium/platinum/silver/gold, gold/germanium/palladium/gold, palladium/germanium/titanium/palladium/gold, and palladium/germanium/titanium/palladium/gold/silver. The solar cell includes top subcell composed of indium gallium phosphorus, middle subcell composed of an Gallium arsenide, Gallium indium phosphorus, Gallium indium arsenide, Gallium arsenide antimony, or Gallium indium arsenide nitrogen emitter region and Gallium indium arsenide nitrogen, bottom subcell composed of an indium gallium arsenide base and emitter layer, or a indium gallium arsenide base layer and a indium gallium phosphorus emitter layer, and graded interlayer composed of indium gallium aluminum arsenide.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a solar cell.    Substrate (101)    Buffer layer (102)    Stop layer (103)    Semiconductor contact layer (104)    Metal contact layer (123)