Super self-aligned technology for backside contact solar cells. A route to low cost and high efficiency

A new technology is proposed for backside contact (BSC) silicon solar cells. This technology is self-aligned since only one photolithography step, without alignment, is required instead of the four to six steps required in previous technologies. Compared to a recently reported self-aligned process for BSC cells, this one eliminates the problem of compensated regions and has the advantages of a reduction of the emitter area, a passivation of silicon surface with thermal oxide between metal fingers, and a reduction in the metal-silicon contact area. As a consequence, this self-aligned technology offers great potential for the fabrication of high-efficiency solar cells at a low cost