Monolithic photodetector

Abstract

A photodetector including a photodiode formed in a semiconductor substrate and a waveguide element formed of a block of a high-index material extending above the photodiode in a thick layer of a dielectric superposed to the substrate, the thick layer being at least as a majority formed of silicon oxide and the block being formed of a polymer of the general formula R1R2R3SiOSiR1R2R3 where R1, R2, and R3 are any carbonaceous or metal substituents and where one of R1, R2, or R3 is a carbonaceous substituent having at least four carbon atoms and/or at least one oxygen atom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will be discussed in detail in the following non-limiting description of specific embodiments in connection with FIG. 1, previously described, which is a partial cross-sectional view of a known image acquisition device.

Claims

1. A photodetector comprising a photodiode formed in a semiconductor substrate and a waveguide element formed of a block of a high-index material extending vertically above the photodiode in a thick layer of a dielectric superposed to the substrate, the thick layer being at least as a majority formed of silicon oxide and the block being formed of a polymer having the general formula.

2. The photodetector of claim 1, wherein said block exhibits a ratio between its depth and its average diameter of greater than 2.

3. The photodetector of claim 1, wherein a colored filter is placed above the block.

4. The photodetector of claim 1, wherein a converging lens is straight above the block.

5. The photodetector of claim 1, wherein a converging lens is placed above the block and is laterally offset with respect to said block.

6. The photodetector of claim 1, wherein the polymer is an SOG-type glass comprising tantalum, titanium, and/or zirconium inclusions.

7. An image acquisition device, comprising a plurality of photodetectors of claim 1.

8. A photodetector array comprising a plurality of photodetectors formed on a substrate, the photodectors being arranged in rows and columns and each photodetector comprising: a photodiode formed in the substrate;a waveguide including,a dielectric layer formed on the photodiode; anda polymer element formed in the dielectric layer adjacent the photodiode, the polymer having the general formula R1R2R3SiOSiR1R2R3 where R1, R2, and R3 are any carbonaceous or metal substituents and where one of R1, R2, or R3 is a carbonaceous substituent having at least four carbon atoms and/or at least one oxygen atom.

9. The photodetector array of claim 8 wherein the polymer element of each photodetector has a depth and an average diameter, and wherein the ratio of the depth to the average diameter is greater than 2.

10. The photodetector array of claim 8 wherein each photodetector further comprises a color filter formed on the silicon oxide dielectric layer adjacent the photodiode.

11. The photodetector array of claim 8 wherein the dielectric layer comprises a plurality of layers.

12. The photodetector array of claim 11 wherein the dielectric layer has an overall thickness and wherein the plurality of layers includes at least one silicon oxide layer, a thickness of all the silicon oxide layers being at least one half the overall thickness of dielectric layer.

13. The photodetector array of claim 8 wherein the polymer element comprises a siloxane polymer element has a general formula of R1R2R3SiOSiR1R2R3, wherein R1, R2, and R3 are any carbonaceous or metal substituents such as tantalum, titanium, or zirconium compounds.

14. The photodetector array of claim 13 wherein the dielectric layer comprises silicon oxide having a refraction index of 1.43 and wherein R1, R2, and R3 have a refraction index that is greater than 1.43.

15. The photodetector array of claim 8 wherein the substrate comprises a semiconductor substrate.

16. The photodetector array of claim 8 further comprising a plurality of metal interconnects, each metal interconnect being formed between adjacent photodiodes.

17. An electronic device, comprising: electronic circuitry; andan image acquisition device coupled to the electronic circuitry, the image acquisition device including a photodetector array having a plurality of photodetectors formed on a substrate, the photodectors being arranged in rows and columns and each photodetector comprising:a photodiode formed in the substrate;a waveguide including,a dielectric layer formed on the photodiode; anda polymer element formed in the dielectric layer adjacent the photodiode, the polymer element having the general formula R1R2R3SiOSiR1R2R3 where R1, R2, and R3 are any carbonaceous or metal substituents and where one of R1, R2, or R3 is a carbonaceous substituent having at least four carbon atoms and/or at least one oxygen atom.

18. The electronic device of claim 17 wherein the electronic circuitry comprises at least one of digital camera and video camera circuitry.

19. The electronic device of claim 17 wherein the electronic circuitry further comprises at least one of cellular telephone and personal digital assistant circuitry.

20. A method of forming a photodetector array including a plurality of photodetectors, the method comprising: forming a plurality of photodiodes in the substrate, each photodiode being associated with a respective photodetector;forming a dielectric layer on the substrate and photodiodes;forming in the dielectric layer adjacent each photodiode an opening, each opening being associated with the adjacent photodetector;forming in each opening a polymer element, the polymer element and portion of the dielectric adjacent each photodiode forming a respective photodetector, and wherein the polymer element has the general formula R1R2R3SiOSiR1R2R3 where R1, R2, and R3 are any carbonaceous or metal substituents and where one of R1, R2, or R3 is a carbonaceous substituent having at least four carbon atoms and/or at least one oxygen atom.

21. The method of claim 20 wherein forming in each opening the polymer element comprises forming the quasi-inorganic siloxane polymer elements through a spin-on-glass process.

22. The method of claim 20 wherein the polymer elements comprise siloxane polymer elements have an index of refraction of between 1.56 to 1.6 or 1.64 to 1.7, and wherein the dielectric layer comprises silicon oxide having an index of refraction of 1.43.