Backside illuminated image sensor with stressed film

摘要

An image sensor includes a photosensitive region disposed within a semiconductor layer and a stress adjusting layer. The photosensitive region is sensitive to light incident through a first side of the image sensor to collect an image charge. The stress adjusting layer is disposed over the first side of the semiconductor layer to establish a stress characteristic that encourages photo-generated charge carriers to migrate towards the photosensitive region.

主权项

1. An image sensor, comprising:
an epitaxial layer; an array of pixels each including a photosensitive region disposed within the epitaxial layer, the photosensitive region positioned to collect an image charge in response to light incident through a first side of the epitaxial layer; and a first stress adjusting layer disposed over the first side of the epitaxial layer establishing a first stress characteristic on the epitaxial layer to encourage photo-generated charge carriers to migrate towards a second side of the epitaxial layer opposite of the first side, wherein the first stress adjusting layer is disposed on the epitaxial layer to apply a patterned stress characteristic to the epitaxial layer such that the first stress adjusting layer applies the first stress characteristic to a first portion of a given pixel on the first side of the epitaxial layer while substantially not applying the first stress characteristic to a second portion of the given pixel on the first side of the epitaxial layer.