Method for producing optoelectronic devices
A method for manufacturing a first optoelectronic device operating at a wavelength λ 1 and a second optoelectronic device operating at a wavelength λ 2>λ1 , the first device comprising a first stack comprising a first encapsulation layer of thickness e 10 and layers of thickness e 1 i (i=1 . . . n), and the second device comprising a second stack comprising a second encapsulation layer of thickness e 20 and layers of thickness e 2 i (i=1 . . . n). The method includes forming the second stack by sizing the thicknesses e 20 and e 2 i according to λ 2 , forming the first stack by sizing the thicknesses e 1 i by homothety and adjusting the thickness e 10 such that the stacks have the same height, and performing out one same technological step on the stacks.
1 . A method for manufacturing at least one first optoelectronic device operating at a first wavelength λ 1 and a second optoelectronic device operating at a second wavelength λ 2 >λ 1 , the first optoelectronic device comprising a first stack along a direction z on a first substrate, the first stack comprising a first lower encapsulation layer of thickness e 10 along the direction z and a plurality of first layers of thickness e 1 i (i=1 . . . n) along the direction z, and the second optoelectronic device comprising a second stack along the direction z on a second substrate, the second stack comprising a second lower encapsulation layer of thickness e 20 along the direction z and a plurality of second layers of thickness e 2 i (i=1 . . . n) along the direction z, said second layers of thickness e 2 i having optical functions similar to those of the first layers of thickness e 1 i , the method comprising:
forming the second stack on the second substrate by sizing the thicknesses e 20 and e 2 i , i=1 . . . n, according to the second wavelength λ 2 ,
forming the first stack on the first substrate by sizing the thicknesses e 10 and e 1 i according to:
e
1
i
=
e
2
i
·
λ
1
λ
2
·
α
i
with
0.7
≤
α
i
≤
1.3
e
10
=
e
20
+
∑
i
=
1
n
e
2
i
-
∑
i
=
1
n
e
1
i
,
and
performing at least one same technological step on the first and second stacks, including an etching of the first and second stacks along one same depth along z, so as to obtain the first and second optoelectronic devices,
wherein the first and second stacks each comprise exactly n+1 layers with n≥2, and have a same total height,
e 10 is calculated such that e 10 ≠e 20 ,
the first stack is formed directly on the first substrate, and
the second stack is formed directly on the second substrate.
2 . The method according to claim 1 , wherein the at least one same technological step comprises one or more steps taken from among: an etching along z of a waveguide pattern, a passivation, a formation of an upper electric contact, a formation of a lower electric contact, or a metallisation.
3 . The method according to claim 1 , wherein the plurality of first layers of thickness e 1 i comprises at least one first active layer of thickness e 11 along z, to emit or receive a radiation having the first wavelength λ 1 , and a first upper encapsulation layer of thickness e 12 along z, and
wherein the plurality of second layers of thickness e 2 i comprises at least one second active layer of thickness e 21 along z, to emit or receive a radiation having the second wavelength λ 2 , and a second upper encapsulation layer of thickness e 22 along z.
4 . The method according to claim 3 , wherein the plurality of first layers of thickness e 1 i further comprises a first lower optical confinement layer of thickness e 13 inserted between the first lower encapsulation layer and the first active layer, and a first upper optical confinement layer of thickness e 14 inserted between the first upper encapsulation layer and the first active layer, and
wherein the plurality of second layers of thickness e 2 i further comprises a second lower optical confinement layer of thickness e 23 inserted between the second lower encapsulation layer and the second active layer, and a second upper optical confinement layer of thickness e 24 inserted between the second upper encapsulation layer and the second active layer with:
e
11
=
e
21
·
λ
1
λ
2
·
α
1
with
0.7
≤
α
1
≤
1.3
,
e
12
=
e
22
·
λ
1
λ
2
·
α
2
with
0.7
≤
α
2
≤
1.3
,
e
13
=
e
23
·
λ
1
λ
2
·
α
3
with
0.7
≤
α
3
≤
1.3
,
e
14
=
e
24
·
λ
1
λ
2
·
α
4
with
0.7
≤
α
4
≤
1.3
,
and
e
10
=
(
e
20
+
e
21
+
e
22
+
e
23
+
e
24
)
-
(
e
12
+
e
11
+
e
13
+
e
14
)
.
5 . The method according to claim 4 , wherein the plurality of first layers of thickness e 1 i further comprises a first stop layer of thickness e 15 under the first lower encapsulation layer, and
wherein the plurality of second layers of thickness e 2 i further comprises a second stop layer of thickness e 25 under the second lower encapsulation layer, with:
e
15
=
e
25
·
λ
1
λ
2
·
α
25
with
0.7
≤
α
5
≤
1.3
.
6 . The method according to claim 1 , wherein the first and second stacks are etched along one same depth h along z to form first and second protruding structures, respectively having a first width W 1 along a direction x and a first length L 1 along a direction y, and a second width W 2 along the direction x and a second length L 2 along the direction y, said method further comprising, before etching of the first and second stacks:
determining the second width W 2 and the second length L 2 according to the second wavelength λ 2 , and
determining the first width W 1 and the first length L 1 according to:
W
1
=
W
2
·
λ
1
λ
2
·
α
W
with
0.7
≤
α
W
≤
1.3
,
and
L
1
=
L
2
·
λ
1
λ
2
·
α
L
with
0.7
≤
α
L
≤
1.3
.
7 . The method of claim 6 , wherein W 1 ≠W 2 .
8 . The method according to claim 1 , further comprising a first etching configured to form a first array having a first depth on the first stack carried by the first substrate, and independently a second etching configured to form a second array having a second depth on the second stack carried by the second substrate.
9 . The method according to claim 1 , wherein the first and second wavelengths λ 1 , λ 2 are chosen in a medium infrared range of between 2 μm and 15 μm.
10 . The method of claim 1 , wherein e 2 i ≠e 1 i for at least one value of i.
11 . A system for manufacturing at least one first optoelectronic device operating at a first wavelength λ 1 and a second optoelectronic device operating at a second wavelength λ 2 >λ 1 , the system comprising at least one first substrate carrying a first stack along a direction z comprising a first lower encapsulation layer of thickness e 10 along the direction z and a plurality of first layers of thickness e 1 i (i=1 . . . n) along the direction z, and a second substrate carrying a second stack along the direction z comprising a second lower encapsulation layer of thickness e 20 along the direction z and a plurality of second layers of thickness e 2 i (i=1 . . . n) along the direction z, said second layers of thickness e 2 i having optical functions similar to those of the first layers of thickness e 1 i , the thicknesses e 10 , e 20 and e 1 i , e 2 i satisfying the following relationships:
e
1
i
=
e
2
i
·
λ
1
λ
2
·
α
i
with
0.7
≤
α
i
≤
1.3
,
and
e
10
=
e
20
+
∑
i
=
1
n
e
2
i
-
∑
i
=
1
n
e
1
i
such that the first and second stacks have substantially one same height along z,
wherein the first and second stacks each comprise exactly n+1 layers with n≥2, and have a same total height,
e
10
≠
e
2
0
,
the first stack is formed directly on the first substrate, and
the second stack is formed directly on the second substrate.
12 . The system according to claim 11 , wherein the first stack is bordered by first trenches of depth h along the direction z and forms a first protruding structure, and the second stack is bordered by second trenches of a same depth h along the direction z and forms a second protruding structure.
13 . The system according to claim 12 , wherein the first protruding structure has a first width W 1 along a direction x and a first length L 1 along a direction y, and the second protruding structure has a second width W 2 along the direction x and a second length L 2 along the direction y, the first and second widths W 1 , W 2 and the first and second lengths L 1 , L 2 verifying the following relationships:
W
1
=
W
2
·
λ
1
λ
2
·
α
W
with
0.7
≤
α
W
≤
1.3
,
and
L
1
=
L
2
·
λ
1
λ
2
·
α
L
with
0.7
≤
α
L
≤
1.3
.
14 . The system of claim 13 , wherein W 1 ≠W 2 .
15 . The system according to claim 11 , wherein the plurality of first layers of thickness e 1 i comprises at least one first active layer of thickness e 11 along z, intended to emit or receive a radiation having the first wavelength 21 , and a first upper encapsulation layer of thickness e 12 along z, and
wherein the plurality of second layers of thickness e 2 i comprises at least one second active layer of thickness e 21 along z, intended to emit or receive a radiation having the second wavelength λ 2 , and a second upper encapsulation layer of thickness e 22 along z, with:
e
12
=
e
22
·
λ
1
λ
2
·
α
2
with
0.7
≤
α
2
≤
1.3
,
and
e
11
=
e
21
·
λ
1
λ
2
·
α
1
with
0.7
≤
α
1
≤
1.3
.
16 . The system according to claim 11 , wherein the first and second substrates are based on silicon, and wherein the first and second stacks are based on III-V materials, the first and second stacks respectively comprising first and second optical isolation layers configured to avoid an optical coupling at the wavelengths λ 1 and λ 2 with the first and second substrates.
17 . The system according to claim 11 , wherein the first and second optoelectronic devices correspond to first and second distributed feedback quantum cascade lasers.