Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie Atomique

Jacques Baylet

Olivier Gravrand

A bispectral detector comprising upper and lower semiconductor layers of a first conductivity type in order to absorb a first and a second electromagnetic spectrum, separated by an intermediate layer that forms a barrier; semiconductor zones of a second conductivity type implanted in upper layer and lower layer and each implanted at least partially in the bottom of an opening that passes through upper layer and intermediate layer; and conductor elements connected to semiconductor zones. At least that part of each opening that passes through upper layer is separated from the latter by a semiconductor cap layer: whereof the concentration of dopants of the second conductivity type is greater than 10cm; and whereof the thickness is chosen as a function of said concentration so that it exceeds the minority carrier diffusion length in the cap layer.

Bispectral multilayer photodiode detector and method for manufacturing such a detector

This bispectral detector comprises a plurality of unitary elements for detecting a first and a second electromagnetic radiation range, consisting of a stack of upper and lower semiconductor layers of a first conductivity type which are separated by an intermediate layer that forms a potential barrier between the upper and lower layers; and for each unitary detection element, two upper and lower semiconductor zones of a second conductivity type opposite to the first conductivity type, are arranged respectively so that they are in contact with the upper faces of the upper and lower layers so as to form PN junctions, the semiconductor zone being positioned, at least partially, in the bottom of an opening that passes through the upper and intermediate layers. The upper face of at least one of the upper and lower layers is entirely covered in a semiconductor layer of the second conductivity type. Cuts are made around each unitary detection element from the upper face of the stack and at least through the thickness of each semiconductor layer of the second conductivity type, entirely covering one or other of the upper and lower semiconductor layers of the first conductivity type, so as to form semiconductor zones of the second conductivity type.

Multilayer bispectral photodiode detector

On a front face of a substrate transparent to the radiation considered, pixels are confined in a stack of absorbent semi-conducting material layers by a network of channels. An insulating layer covers the bottom and the side walls of the channels. An electrically conducting layer covers the insulating layer on the bottom and on the side walls of the channels confining at least a part of the pixels. The conducting layer can be voltage polarized.

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Grenoble, France

Jacques Baylet