Integration of Solar Cells on Top of CMOS Chips Part I: a-Si Solar Cells

We present the monolithic integration of deep-submicrometer complementary metal-oxide-semiconductor (CMOS) microchips with a-Si: H solar cells. Solar cells are manufactured directly on the CMOS chips. The microchips maintain comparable electronic performance, and the solar cells show efficiency values above 7%. The yield of photovoltaic cells on planarized CMOS chips is 92%. This integration allows integrated energy harvesting using established process technologies and, as such, is an important step toward wireless autonomous microsystems (i.e., smart dust).