초록 ▼

Photodiode arrays are formed with close diode-to-diode spacing and minimized cross-talk between diodes in the array by isolating the diodes from one another with trenches that are formed between the photodiodes in the array. The photodiodes are formed of spaced regions in a base layer, each spaced r

Photodiode arrays are formed with close diode-to-diode spacing and minimized cross-talk between diodes in the array by isolating the diodes from one another with trenches that are formed between the photodiodes in the array. The photodiodes are formed of spaced regions in a base layer, each spaced region having an impurity type opposite to that of the base layer to define a p-n junction between the spaced regions and the base layer. The base layer meets a substrate at a boundary, with the substrate being much more heavily doped than the base layer with the same impurity type. The trenches extend through the base layer and preferably into the substrate. Minority carriers generated by absorption of light photons in the base layer can only migrate to an adjacent photodiode through the substrate. The lifetime and the corresponding diffusion length of the minority carriers in the substrate is very short so that all minority carriers recombine in the substrate before reaching an adjacent photodiode.

대표청구항 ▼

[ What is claimed is:] [1.] Isolated semiconductor photodiode structure comprising:(a) a substrate of semiconductor having a high doping density of a selected impurity type;(b) a base layer of semiconductor meeting the substrate at a boundary and having the same impurity type as the substrate at a l

[ What is claimed is:] [1.] Isolated semiconductor photodiode structure comprising:(a) a substrate of semiconductor having a high doping density of a selected impurity type;(b) a base layer of semiconductor meeting the substrate at a boundary and having the same impurity type as the substrate at a lower doping density than the substrate, wherein the base layer has a top surface and the base layer is at least as thick as the absorption length in the base layer of the light to which the structure will be exposed;(c) at least two spaced regions of semiconductor in contact with the base layer, the spaced regions doped with an impurity type opposite to the impurity type of the base layer such that each spaced region forms a p-n junction with the base layer; and(d) a trench in the base layer between the spaced regions that is not covered and that extends at least to the boundary between the substrate and the base layer, the trench spaced from the p-n junctions defined between the spaced regions and the base layer so that the trench does not expose a p-n junction, the width of the trench selected such that the path of minority carriers migrating from one side of the trench to the other through the substrate is greater than the diffusion length of the minority carriers in the substrate and wherein the trench has sidewalls that are parallel to each other and perpendicular to the top surface and a depth greater than its width.