Image sensor with improved optical response uniformity
View Patent ↗An image sensor includes a semiconductor substrate; a photosensor having, a first photosensing region including a first stack of one or more layers of transparent materials covering the substrate, the first photosensing region having a spectral response having minima and maxima as a function of wavelength of light; a second photosensing region including a second stack of one or more layers of transparent materials covering the substrate, the second photosensing region having a spectral response having maxima and minima; and a third photosensing region including a third stack of one or more layers of transparent materials covering the substrate, the third photosensing region having a spectral response having maxima and minima; and wherein at least one maximum or minimum of the spectral response of the separate regions is matched with a minimum or maximum such that the average spectral response of the photosensor has less variation with wavelength of light than the individual spectral responses of each of the separate photosensing regions.
1. An image sensor, comprising:
a) a semiconductor substrate;
b) a photosensor having,
i) a first photosensing region including a first stack of one or more layers of transparent materials covering the substrate, the first photosensing region having a spectral response having first minima and first maxima as a function of wavelength of light;
ii) a second photosensing region including a second stack of one or more layers of transparent materials covering the substrate, the second photosensing region having a spectral response having second maxima and second minima; and
iii) a third photosensing region including a third stack of one or more layers of transparent materials covering the substrate, the third photosensing region having a spectral response having third maxima and third minima; and
c) wherein at least one maximum or minimum of the spectral response of one of the photosensing regions is substantially matched with a minimum or maximum of another photosensing region such that the average special response of the photosensor has less variation with wavelength of light than the individual spectral responses of each of the separate photosensing regions.
2. The image sensor as in claim 1 , wherein the number of layers and the materials in the separate regions are identical, and the thickness of one or more layers is different.
3. The image sensor as in claim 1 , wherein the number of layers in two or more of the separate stacks and/or the materials is different.
4. The image sensor as in claim 1 , wherein one of the layers in each stack is a gate electrode layer.
5. The image sensor as in claim 4 , wherein at least one gate electrode layer is indium tin oxide.
6. The image sensor as in claim 5 , wherein the gate electrode layer includes two or more stacks that are indium tin oxide.
7. The image sensor as in claim 6 , wherein the gate electrode layers in two or more stacks are of different thicknesses.
8. The image sensor as in claim 1 further comprising a fourth photosensing region including a fourth stack of one or more layers of transparent materials covering the substrate, the fourth photosensing region having a spectral response having maxima and minima.
9. The image sensor as in claim 8 further comprising five or more photosensing regions including five or more stacks each of one or more layers of transparent materials covering the substrate, the five or more photosensing regions each having a spectral response having maxima and minima.