Dark current reduction in back-illuminated imaging sensors

摘要

A method for fabricating a back-illuminated semiconductor imaging device on a semiconductor-on-insulator substrate, and resulting imaging device is disclosed. The device includes an insulator layer; a semiconductor substrate, having an interface with the insulator layer; an epitaxial layer grown on the semiconductor substrate by epitaxial growth; and one or more imaging components in the epitaxial layer in proximity to a face of the epitaxial layer, the face being opposite the interface of the semiconductor substrate and the insulator layer, the imaging components comprising junctions within the epitaxial layer; wherein the semiconductor substrate and the epitaxial layer exhibit a net doping concentration having a maximum value at a predetermined distance from the interface of the insulating layer and the semiconductor substrate and which decreases monotonically on both sides of the profile from the maximum value within a portion of the semiconductor substrate and the epitaxial layer. The doping profile between the interface with the insulation layer and the peak of the doping profile functions as a “dead band” to prevent dark current carriers from penetrating to the front side of the device.

主权项

1. A semiconductor device, comprising:
an insulator layer; a semiconductor substrate, having an interface with the insulator layer on a first side; and an epitaxial layer grown on the semiconductor substrate by epitaxial growth, the epitaxial layer on a side of the semiconductor substrate opposite the first side; wherein the semiconductor substrate and the epitaxial layer exhibit a net doping concentration having a maximum value in the semiconductor substrate at a predetermined distance from the interface of the insulator layer and the semiconductor substrate and which increases monotonically from the interface to the maximum value and decreases monotonically towards the epitaxial layer.