Biosensors for biological or chemical analysis and methods of manufacturing the same
Embodiments of the invention provide an improved biosensor for biological or chemical analysis. According to embodiments of the invention, backside illumination (BSI) complementary metal-oxide-semiconductor (CMOS) image sensors can be used to effectively analyze and measure fluorescence or chemiluminescence of a sample. This measured value can be used to help identify a sample. Embodiments of the invention also provide methods of manufacturing an improved biosensor for biological or chemical analysis and systems and methods of DNA sequencing.
1. A biosensor comprising:
a backside illumination complementary metal-oxide-semiconductor (CMOS) image sensor including:
an electronic circuit layer; and
a photo sensing layer over the electronic circuit layer, wherein the photo sensing layer includes:
a substrate layer, and
a plurality of photodiodes in contact with the electronic circuit layer, and wherein
a light receiving surface is defined by a surface of the plurality of photodiodes opposite to the electronic circuit layer;
a passivation layer on the plurality of photodiodes, wherein the passivation layer is an oxide;
a regular array of spots formed on the passivation layer above the light receiving surface, wherein the spots of the regular array have uniform dimensions and are organized in a pattern in columns and rows, wherein each spot is a discrete positively charged area sized and functionalized to receive and retain a nucleic acid macromolecule, wherein each spot of the array of spots is separated from other spots by areas that are inert in the sense that they are configured to not receive and retain nucleic acid macromolecules, and wherein the biosensor does not comprise a color filter layer configured to filter light by wavelength range using a polymer material;
wherein each of the plurality of photodiodes is characterized by a first linear dimension and the regular array of spots are each characterized by a second linear dimension, and the second linear dimension is smaller than the first linear dimension.
2. The biosensor of claim 1 , wherein the inert areas are characterized by hydrophobic surfaces.
3. The biosensor of claim 2 , wherein each spot is sized and functionalized to contain a DNA nanoball (DNB).