Pixel isolation regions formed with conductive layers

摘要

An image sensor may include isolation regions that are formed in between photodiodes. These isolation regions may prevent cross-talk and improve the performance of the image sensor. The isolation regions may include a conductive layer that is electrically connected to a bias voltage supply line. Biasing the conductive layer may result in a charge inversion in the substrate adjacent to the conductive layer. The charge inversion may prevent the generation of dark current. The conductive layer may be formed on a liner oxide layer in trenches formed in epitaxial silicon. A connecting layer may be used to electrically connect each conductive layer. The connecting layer may be formed integrally with the conductive layer or formed from a separate material.

主权项

1. An image sensor comprising:
a substrate containing an array of photodiodes, wherein the substrate has a top surface; a plurality of isolation regions, wherein each isolation region is interposed between a pair of adjacent photodiodes in the array of photodiodes; and a plurality of conductive layers, wherein each conductive layer is formed in a respective isolation region, wherein each conductive layer is electrically connected to a bias voltage supply line, wherein each isolation region comprises a trench in the substrate, wherein each conductive layer is formed in a respective trench, wherein each conductive layer has at least a portion formed below the top surface of the substrate, and wherein each conductive layer is formed in direct contact with the substrate without an intervening liner.