| 摘要 |
A backside illuminated image sensor or a method of manufacturing a backside illuminated image sensor comprising semiconductor devices (e.g. photodiodes or switches) in a layer of semiconductor material (e.g. p-type epitaxial silicon) and a layer of aluminium oxide (sapphire/alumina/Al2O3) on the semiconductor material. The Al2O3has a thickness of between 1nm - 5µm and may be patterned. Additional layers for anti-reflection (e.g. SiN or SiO2), passivation, colour filter patterns and micro-lenses may be deposited on the Al2O3(figs. 8 and 9). The semiconductor material may be deposited on a substrate and after forming the semiconductor devices, parts of the substrate can be removed prior to depositing Al2O3on the semiconductor material. The semiconductor material and Al2O3may be deposited on a mechanical carrier layer and the semiconductor devices may be formed followed by removal of the carrier layer (figs. 6 and 7). The Al2O3is a passivation for the backside surface of the image sensor which reduces dark current by forming an accumulation layer in the semiconductor material. No photoelectric charges are trapped and thermally generated charges recombine. An inversion layer may be formed under a transparent gate e.g. Indium Tin Oxide (ITO) deposited at the backside surface (fig. 5). |
