Inverted metamorphic multijunction solar cells with back contacts

Abstract

A method of manufacturing a solar cell by providing a first substrate; depositing sequentially on the first substrate a plurality of semiconductor layers, the plurality of semiconductor layers comprising a first layer and a last layer in the direction of deposition; forming a backside contact layer on the last semiconductor layer; forming on the last semiconductor layer a back cathode contact isolated from at least a first portion of the backside contact layer, the first portion forming the anode contact; attaching a second substrate on the backside contact layer and removing the first substrate to expose the first semiconductor layer and to define a front surface and an opposite back surface of a solar cell; forming a front cathode contact on the front surface of the solar cell; etching a first trench through the plurality of semiconductor layers to define an active portion of the solar cell with a first mesa structure including the front cathode contact and the anode contact and being surrounded by the first trench, the first mesa having a first sidewall in the first trench and a lateral peripheral region beyond the sidewall, and forming in the lateral peripheral region an electrically conductive layer extending from the front surface where it is electrically connected to the front cathode contact along the first sidewall of the first trench to be electrically connected to the back cathode contact.