Method for fabricating a photodiode structure and photodiode structure

IL304045BActive Publication Date: 2026-08-01LYNRED
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Patent Information

Application Number
IL304045
Authority / Receiving Office
IL · IL
Patent Type
Patents
Current Assignee / Owner
Priority Date
2020-12-31
Filing Date
2021-12-30
Publication Date
2026-08-01
Estimated Expiration
2041-12-30

AI Technical Summary

Technical Problem

Existing photodiode manufacturing processes face challenges in achieving efficient channeling of photogenerated carriers due to difficulties in forming precise electrical doping gradients and cadmium concentration profiles, particularly in thin layers, which affects the signal-to-noise ratio and operational frequency of infrared detectors.

Method used

A method involving liquid phase epitaxy to grow HgCdTe layers with continuously decreasing cadmium and electrical dopant concentration gradients, forming a pn or pin junction, where the cadmium concentration gradient ranges from 10% to 25 atomic% and the dopant gradient decreases from concentrations greater than 5.10^18 to less than 2.10^15 at/cm^3, ensuring a thickness of less than 6 microns, facilitating better charge carrier collection.

Benefits of technology

This approach enhances the channeling of photogenerated carriers, improving the signal-to-noise ratio and operational frequency of infrared detectors, leading to more efficient infrared radiation capture and reduced dark current, thus enhancing the overall performance of photodiodes.

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Abstract

A substrate (1) having an upper layer (2) made of a cadmium-doped semiconductor material is provided in order to produce a photodiode structure. A first layer (3) made of HgCdTe is formed by liquid phase epitaxy starting from the upper layer (2) with a bath containing an n-type electrically active dopant for electrically doping the first layer (3). The cadmium diffuses from the upper layer (2) to the first layer (3) to form a cadmium concentration gradient that decreases from the interface with the upper layer (2) moving away from the interface. The cadmium concentration gradient causes a band gap gradient which decreases in the first layer (3) from the interface and causes an n-type dopant concentration gradient in the first layer (2) starting from the interface.
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