CONTROL OF OPTICAL CROSSTALK BETWEEEN ADJACENT PHOTODETECTING REGIONS

摘要

An array [10] of photodetecting active regions [16] includes a layer of photoresponsive material [14] differentiated into a plurality of photodetecting active regions. The layer has a composition which varies across a thickness of the layer from a first surface of the layer to a second surface [14a] of the layer such that a magnitude of an effective energy bandgap of the layer decreases from the first surface to the second surface. A resulting crystal potential field constrains photoexcited minority charge carriers to exist within a region of the layer which is substantially adjacent to the second, narrower energy bandgap surface. The array further includes a plurality of groove structures [18] formed within the second surface of the layer and extending into the layer to a depth less than the thickness of the layer. A groove is interposed between at least two adjacent active regions for substantially preventing minority carriers from laterally diffusing between active regions. The grooves may be combined with ground plane or guard diode structures, each limiting the diffusion of minority charge carriers along a respective axis. The photodetecting active regions may each comprise a reduced area p-n juntion.