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US 12,324,250 B2Granted
Single-photon avalanche photodiode
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorsYounes Benhammou, Dominique Golanski, Denis Rideau
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Abstract
The present disclosure relates to a photodiode comprising a first part made of silicon and a second part made of doped germanium lying on and in contact with the first part, the first part comprising a stack of a first area and of a second area forming a p-n junction and the doping level of the germanium increasing as the distance from the p-n junction increases.
Claims17
A method, comprising:
- forming a first silicon layer doped with a first type of conductivity;
- forming a second silicon layer doped with a second type of conductivity vertically adjacent to the first silicon layer;
- etching a cavity into the second silicon layer;
- and
- forming a germanium layer doped with the second type of conductivity by an epitaxy process from the second silicon layer so as to fill the cavity, the germanium layer being vertically adjacent to the second silicon layer, a doping concentration of the germanium layer increasing toward a distal surface of the germanium layer with respect to the second silicon layer.
2 more elements
A method, comprising:
- forming a photodiode by:
- forming a germanium layer on a first surface of a substrate, the germanium layer having a first conductivity type, the germanium layer having an increasing doping concentration from the first surface to a second surface of the germanium layer, wherein
- the substrate includes a first silicon layer of a second conductivity type that is different from the first conductivity type, a second silicon layer of the first conductivity type that is between the first silicon layer and the first surface of the substrate, and a third silicon layer of the second conductivity type between the first surface of the substrate and the second silicon layer.
A method, comprising:
- forming a photodiode by:
- forming a first doped region in a substrate, the first doped region having a first conductivity type;
- forming a silicon layer on the substrate;
- forming a second doped region in the silicon layer, the second doped region having a second conductivity type that is different from the first conductivity type;
- forming an opening in the second doped region;
- forming a germanium layer in the opening, the germanium layer having the second conductivity type, the germanium layer having a heavier doping concentration than the second doped region.
3 more elements
A method, comprising:
- forming a first silicon layer doped with a first type of conductivity in a substrate of silicon;
- forming a second silicon layer doped with a second type of conductivity vertically adjacent to the first silicon layer, the forming of the second silicon layer including:
- forming an epitaxy layer of silicon from the substrate;
- and
- doping a portion of the epitaxial layer of silicon with the second type of conductivity through a whole thickness of the epitaxy layer of silicon;
- and
- forming a germanium layer doped with the second type of conductivity vertically adjacent to the second silicon layer, a doping concentration of the germanium layer increasing toward a distal surface of the germanium layer with respect to the second silicon layer.
4 more elements
Dependencies are inferred from the claim text.