Light-sensing device for multi-spectral imaging
First Claim
1. A light-sensing device comprising a semiconductor substrate and photodiodes formed thereon, wherein the semiconductor substrate includes side-by-side active areas implanted therein, some with n-type doping, others with p-type doping, and CMOS devices, said active areas being electrically isolated from one another and from the adjacent CMOS device by isolation regions (FOX), the photodiodes having a light-sensing region comprising a stack of layers with at least one superlattice region having interleaved well and barrier layers, the photodiodes being formed by alternating pseudomorphic layers under tensile and compressive strain, each layer incorporating Group IV elements and/or alloys thereof, wherein light can be absorbed in a first type of photodiode by the generation of electron-hole pairs through miniband-to-miniband transitions, and in a second type of photodiode by intersubband transitions, the photodiodes of the first and second types share the same set of epitaxial layers on said active areas, wherein when the doping in the epitaxial layers is of the opposite polarity of that in the active area, a photodiode of the first type is formed, and when the doping in the epitaxial layers is of the same polarity of that in the active area, a photodiode of the second type is formed.
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Abstract
A method of fabricating multi-spectral photo-sensors including photo-diodes incorporating stacked epitaxial superlattices monolithically integrated with CMOS devices on a common semiconductor substrate.
30 Citations
20 Claims
- 1. A light-sensing device comprising a semiconductor substrate and photodiodes formed thereon, wherein the semiconductor substrate includes side-by-side active areas implanted therein, some with n-type doping, others with p-type doping, and CMOS devices, said active areas being electrically isolated from one another and from the adjacent CMOS device by isolation regions (FOX), the photodiodes having a light-sensing region comprising a stack of layers with at least one superlattice region having interleaved well and barrier layers, the photodiodes being formed by alternating pseudomorphic layers under tensile and compressive strain, each layer incorporating Group IV elements and/or alloys thereof, wherein light can be absorbed in a first type of photodiode by the generation of electron-hole pairs through miniband-to-miniband transitions, and in a second type of photodiode by intersubband transitions, the photodiodes of the first and second types share the same set of epitaxial layers on said active areas, wherein when the doping in the epitaxial layers is of the opposite polarity of that in the active area, a photodiode of the first type is formed, and when the doping in the epitaxial layers is of the same polarity of that in the active area, a photodiode of the second type is formed.
- 18. A light-sensing device comprising a semiconductor substrate and photodiodes formed thereon, wherein the semiconductor substrate includes side-by-side active areas implanted therein, some with n-type doping, others with p-type doping, and CMOS devices, said active areas being electrically isolated from one another and from the adjacent CMOS device by isolation regions (FOX), the photodiodes having a light-sensing region comprising a stack of layers with at least one superlattice region having interleaved well and barrier layers, the photodiodes being formed by alternating pseudomorphic layers under tensile and compressive strain, each layer incorporating Group IV elements and/or alloys thereof, wherein light can be absorbed in a first type of photodiode by the generation of electron-hole pairs through miniband-to-miniband transitions, and in a second type of photodiode by intersubband transitions, the photodiodes of the first and second types share the same set of epitaxial layers on said active areas, wherein when the doping in the epitaxial layers is of the opposite polarity of that in the active area, a photodiode of the first type is formed, and when the doping in the epitaxial layers is of the same polarity of that in the active area, a photodiode of the second type is formed.
Specification