Trench photodetector
First Claim
1. A method of forming a PIN photodetector having a set of p and n regions separated by a set of photon detector regions in a solid state wafer comprising the steps of:
- Simultaneously forming two sets of deep trenches, separated by a set of photon detection regions, in said solid state wafer, one wide set of trenches being wider than the other narrow set, such that the wide set has a remaining central aperture when the narrower set is filled with a conformally deposited material;
Filling the narrow trenches and conformally partially filling the wide trenches with a first material doped with a first type of dopant;
Removing the first material from the wide trenches;
Depositing a second material doped with a second type of dopant of opposite polarity from said first type of dopant in the wide trenches;
Annealing the wafer to drive the first and second types of dopants into the substrate to form the p and n regions of the PIN photodetector;
Removing the first and second materials from both the wide and narrow trenches; and
Filling both the wide and narrow trenches with a conductive material to form conductive electrodes connected to said p and n regions in both the wide and narrow trenches.
3 Assignments
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Accused Products
Abstract
Trench type PIN photodetectors are formed by etching two sets of trenches simultaneously in a semiconductor substrate, the wide trenches having a width more than twice as great as the narrow trenches by a process margin; conformally filling both types of trenches with a sacrificial material doped with a first dopant and having a first thickness slightly greater than one half the width of the narrow trenches, so that the wide trenches have a remaining central aperture; stripping the sacrificial material from the wide trenches in an etch that removes a first thickness, thereby emptying the wide trenches; a) filling the wide trenches with a second sacrificial material of opposite polarity; or b) doping the wide trenches from the ambient such as by gas phase doping, plasma doping, ion implantation, liquid phase doping, infusion doping and plasma immersion ion implantation; diffusing the dopants into the substrate, forming p and n regions of the PIN diode; removing the first and the second sacrificial materials, and filling both the wide and the narrow sets of trenches with the same conductive material in contact with the diffused p and n regions.
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Citations
12 Claims
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1. A method of forming a PIN photodetector having a set of p and n regions separated by a set of photon detector regions in a solid state wafer comprising the steps of:
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Simultaneously forming two sets of deep trenches, separated by a set of photon detection regions, in said solid state wafer, one wide set of trenches being wider than the other narrow set, such that the wide set has a remaining central aperture when the narrower set is filled with a conformally deposited material; Filling the narrow trenches and conformally partially filling the wide trenches with a first material doped with a first type of dopant; Removing the first material from the wide trenches; Depositing a second material doped with a second type of dopant of opposite polarity from said first type of dopant in the wide trenches; Annealing the wafer to drive the first and second types of dopants into the substrate to form the p and n regions of the PIN photodetector; Removing the first and second materials from both the wide and narrow trenches; and Filling both the wide and narrow trenches with a conductive material to form conductive electrodes connected to said p and n regions in both the wide and narrow trenches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of forming a PIN photodetector having a set of p and n regions separated by a set of photon detector regions in a solid state wafer comprising the steps of:
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Simultaneously forming two sets of trenches, separated by a set of photon detection regions, in said solid state wafer, one wide set of trenches being wider than the other narrow set, such that the wide set has a remaining central aperture when the narrower set is filled with a conformally deposited material; Filling the narrow trenches and conformally partially filling the wide trenches with a first material doped with a first type of dopant; Removing the first material from the wide trenches; Doping the wide trenches with a second type of dopant of opposite polarity by a doping method selected from the group consisting of gas phase doping, plasma doping, ion implantation, liquid phase doping, infusion doping, and plasma immersion ion implantation; Annealing the wafer to drive the first and second types of dopants into the substrate to form the p and n regions of the PIN photodetector; Removing the first material from the narrow trenches; and Forming conductive material connected to said p and n regions in both the wide and narrow trenches. - View Dependent Claims (10, 11, 12)
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Specification