Photodetector optimized by metal texturing provided on the rear surface
AssigneeCommissariat A L'energie Atomique Et Aux Energies Alternatives
InventorsRoch Espiau De Lamaestre, Salim Boutami, Olivier Gravrand, Jérôme Le Perchec
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Abstract
Backlit detector for the detection of electromagnetic radiation around a predetermined wavelength, including a semiconductor absorption layer, formed above a transparent medium, capable of transmitting at least some of said radiation, and a mirror above the semiconductor layer, and placed between the mirror and the semiconductor layer, a periodic grating of metallic patterns, the mirror and the grating being included in a layer of material transparent to said radiation and formed on the semiconductor layer.
Claims23
A backlit detector for the detection of electromagnetic radiation around a predetermined wavelength, including:
- a semiconductor absorption layer for the absorption of said radiation, formed above a medium at least partially transparent to said radiation, and having a thickness capable of transmitting at least some of said radiation;
- and
- a mirror placed above the semiconductor layer to reflect radiation received therethrough,
- wherein it comprises, placed between the mirror and the semiconductor layer, a periodic grating of metallic patterns, the mirror and the periodic grating being included in a layer of material at least partially transparent to said radiation and formed on the semiconductor layer,
- and wherein the mirror and the periodic grating of metallic patterns are designed to verify the following relations:
- d
- ≤
- λ
- Re
-
- (
- n
- 1
- )
- λ
- 16
- ×
- Re
-
- (
- n
- 2
- )
- +
- m
- ×
- λ
- 2
- ×
- Re
-
- (
- n
- 2
- )
- ≤
- h
- ≤
- 3
- ×
- λ
- 8
- ×
- Re
-
- (
- n
- 2
- )
- +
- m
- ×
- λ
- 2
- ×
- Re
-
- (
- n
- 2
- )
- Re
-
- (
- n
- 2
- )
- ≤
- 1
- ,
- 3
- ×
- Re
-
- (
- n
- 1
- )
- Re
-
- (
- n
- 1
- )
- ≥
- Re
-
- (
- n
- substrat
- )
- where
- Re denotes the real component;
- d is the distance between the semiconductor layer and the periodic grating,
- h is the distance between the mirror and the periodic grating,
- m is a positive or null integer,
- λ is a wavelength at which the semiconductor layer is absorbent,
- n1 is the refractive index of the semiconductor layer,
- n2 is the refractive index of the layer in which the periodic grating and the mirror are formed;
- and
- nsubstrat is the refractive index of the medium above which the semiconductor absorption layer is formed.
Dependencies are inferred from the claim text.