Imaging systems with improved microlenses for enhanced near-infrared detection

Abstract

An imaging device may have an array of image sensor pixels that includes infrared pixels. The infrared pixels may be formed from a silicon layer and having an etched microlens on an upper surface of the silicon layer. The etched microlens may be formed as concentric circles, concentric squares, or other concentric shapes to improve the focusing of incident light on the photosensitive portion of the silicon layer. Additionally, there may be a plurality of silicon—silicon-oxide interfaces or silicon—silicon-nitride interfaces between the etched microlens and the silicon layer. These interfaces may increase the absorption of infrared light by the underlying silicon layer. Similar interfaces may be formed on a lower surface, either as an etched region or as an additional dielectric layer. Alternatively or additionally, the infrared pixels may include a conductive patch between the silicon layer and microlens that similarly increases the absorption of infrared light.

Dependencies are inferred from the claim text.