CN100391069C - Device structure and its production for single-modulus quantum cascade laser - Google Patents

Device structure and its production for single-modulus quantum cascade laser Download PDF

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CN100391069C
CN100391069C CNB200510126478XA CN200510126478A CN100391069C CN 100391069 C CN100391069 C CN 100391069C CN B200510126478X A CNB200510126478X A CN B200510126478XA CN 200510126478 A CN200510126478 A CN 200510126478A CN 100391069 C CN100391069 C CN 100391069C
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indium gallium
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gallium arsenic
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CN1983750A (en
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郭瑜
刘峰奇
刘俊岐
王占国
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Institute of Semiconductors of CAS
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Abstract

The invention is concerned with devices structure of single mode quantum cascade laser. It relates to one N type InP underlay, one N type InGaAs lower wave-guide layer made on N type InP underlay, 35 cycle InGaAs / InAlAs commutative active layer on the lower wave-guide layer, one N type InGaAs upper wave-guide layer on active layer, one N type InAlAs upper cladding on the N type InGaAs upper wave-guide layer, one N type InGaAs high doping contact layer on N type InAlAs upper cladding, one N type InGaAs ohm contact layer on N type InGaAs high doping contact layer, one SiO2 dielectric layer on the upper surface and sidewall in type of double grooves of whole material, and the SiO2 dielectric layer is separate to form current injecting window, one frontispiece N type electrode made on the SiO2 dielectric layer and one rear N type electrode made on the back of N type InP underlay.

Description

The device architecture of single mode F-P chamber quantum cascade laser
Technical field
The present invention relates to technical field of semiconductors, be meant the device architecture of a kind of single mode F-P chamber quantum cascade laser especially.
Background technology
Because 3-14 μ m mid and far infrared wave band is very important atmospheric window, all has extremely important application prospect at aspects such as national defence, medical science, environmental protection, detection of gas, chemical spectroscopy, free-space communications, and the excitation wavelength of conventional semiconductor laser is subject to the energy gap of semi-conducting material, less at the occurring in nature low bandgap material, the semiconductor laser that obtain the mid and far infrared wavelength is very difficult.In order to satisfy the application need of centering far infrared band solid light source, scientists is jumped out the classical theory that traditional p-n junction semiconductor laser swashs the mechanism of penetrating, and has proposed the research based on the quantum cascade laser of the intersubband transitions in same conduction band or the valence band.
The invention of quantum cascade laser in 1994 is created much of a stir in the whole world, after this, countries in the world are all numerous and confused has carried out the research of quantum cascade laser in succession because of the absolute importance of 3-14 μ m mid and far infrared wave band atmospheric window, but conventional its live width broad of FP chamber quanta cascade (QC) laser, and show as the work of many longitudinal modes.And, require the live width of laser to be lower than compacting broadening (the about 1cm of gas under the room temperature for detection of gas, contamination monitoring and spectroscopy applications -1), and at several cm -1Scope in can be tuning, promptly quantum cascade laser must be able to be stablized single mode emission, and has controlled tuning range.
The quantum cascade laser of the dynamic single mode operation of current realization mainly is a distributed feedback quanta cascaded laser, and it adopts the holographic exposure method to make grating, and needs the secondary epitaxy growth, and this makes manufacture craft very complicated.
The single mode F-P chamber quantum cascade laser that the present invention proposes need not to make grating, and technology is simple, and technology is reliable, can realize stable sharp the penetrating of single mode.
Summary of the invention
The object of the present invention is to provide the device architecture of a kind of single mode F-P chamber quantum cascade laser, have simplification technology, good reliability can realize stable sharp the penetrating of single mode.
The device architecture of a kind of single mode F-P of the present invention chamber quantum cascade laser is characterized in that, comprising:
One n type indium phosphide substrate is as under-clad layer;
One n type indium gallium arsenic lower waveguide layer, this indium gallium arsenic lower waveguide layer is produced on the n type indium phosphide substrate, is used for improving the refractive index of waveguide core layer, strengthens the light restriction, and this n type indium gallium arsenic lower waveguide layer is a three-stage structure, forms two ditch ridge structures between this three-stage structure;
35 active layers that cycle indium gallium arsenic/indium aluminium arsenic replaces, this active layer is produced on the lower waveguide layer of three-stage structure, as the luminous zone;
Ducting layer on the one n type indium gallium arsenic, ducting layer is produced on the active layer on this indium gallium arsenic, is used for improving the refractive index of waveguide core layer, strengthens the light restriction;
One n type indium aluminium arsenic top covering, this indium aluminium arsenic top covering are produced on the n type indium gallium arsenic on the ducting layer;
One n type indium gallium arsenic high doped contact layer, this n type indium gallium arsenic high doped contact layer is produced on the n type indium aluminium arsenic top covering;
One n type indium gallium arsenic ohmic contact layer, this n type indium gallium arsenic ohmic contact layer is produced on the n type indium gallium arsenic high doped contact layer;
One SiO 2Electric insulation layer, this SiO 2Electric insulation layer is produced on the upper surface of whole material and the sidewall of two ditch ridge structures, this SiO on the ridge of two ditch ridge structures 2The place forms electric current and injects window for disconnecting in the middle of the electric insulation layer;
One positive n type electrode, this front n type electrode is produced on SiO 2On the electric insulation layer, and cover electric current injection window; And
One back side n type electrode, this back side n type electrode is produced on the back side of n type indium phosphide substrate,
Wherein, the chamber length of this laser is less than 145 μ m.
Wherein the width of the ridge table top of two ditch ridge structures is 8-25 μ m, and the width of each ditch is 25-50 μ m.
Wherein the size of electric current injection window is 1/3 of two ditch ridge structure median ridge table top tip size, can guarantee lithography alignment.
Device technology involved in the present invention is simple, and is reliable, avoided the complicated technology in the conventional distributed feedback laser.
Description of drawings
For further specifying structure of the present invention, characteristics, it is as follows to describe the present invention below in conjunction with drawings and the specific embodiments, wherein:
Fig. 1 is the device architecture schematic cross-section of the single mode F-P chamber quantum cascade laser that adopts of the present invention;
Fig. 2 is the long L=1.5mm in chamber, and the sharp spectrogram of penetrating of chamber, the F-P chamber quantum cascade laser of wavelength X=5.4 μ m, spectrum show as multimode and distribute;
Fig. 3 is the long L=0.29mm in chamber, the sharp spectrogram of penetrating of the short cavity quantum cascade laser of wavelength X=5.4 μ m, and device still shows as multimode operation;
Fig. 4 is the long L=0.145mm in chamber, the sharp spectrogram of penetrating of the short cavity quantum cascade laser of wavelength X=5.4 μ m, and device shows as single mode operation;
Fig. 5 is the long L=0.145mm in chamber, the photocurrent characteristics curve of the short cavity quantum cascade laser of wavelength X=5.4 μ m.
Embodiment
See also shown in Figure 1ly, the device architecture of a kind of single mode F-P of the present invention chamber quantum cascade laser is characterized in that, comprising:
One n type indium phosphide substrate 1 is as under-clad layer;
One n type indium gallium arsenic lower waveguide layer 2, this lower waveguide layer 2 is produced on the n type indium phosphide substrate 1, be used for improving the refractive index of waveguide core layer, strengthen the light restriction, this n type indium gallium arsenic lower waveguide layer 2 is a three-stage structure, form two ditch ridge structures between it, the width of the ridge table top of this pair ditch ridge structure is 8-25 μ m, and the width of each ditch is 25-50 μ m;
35 active layers 3 that cycle indium gallium arsenic/indium aluminium arsenic replaces, this active layer 3 is produced on the lower waveguide layer 2 of three-stage structure, as the luminous zone;
Ducting layer 4 on the one n type indium gallium arsenic, ducting layer 4 is produced on the active layer 3 on this indium gallium arsenic, is used for improving the refractive index of waveguide core layer, strengthens the light restriction;
One n type indium aluminium arsenic top covering 5, this indium aluminium arsenic top covering 5 are produced on the n type indium gallium arsenic on the ducting layer 4;
One n type indium gallium arsenic high doped contact layer 6, this n type indium gallium arsenic high doped contact layer 6 is produced on the n type indium aluminium arsenic top covering 5;
One n type indium gallium arsenic ohmic contact layer 7, this n type indium gallium arsenic ohmic contact layer 7 is produced on the n type indium gallium arsenic high doped contact layer 6;
One SiO 2 Electric insulation layer 8, this SiO 2 Electric insulation layer 8 is produced on the upper surface of whole material and the sidewall of two ditch ridge structures, this SiO 2For disconnecting, form electric current and inject window 9 between the electric insulation layer 8, the size that this electric current injects window 9 be two ditch ridge structures ridge table top tip size 1/3, can guarantee lithography alignment;
One positive n type electrode 10, this front n type electrode 10 is produced on SiO 2On the electric insulation layer 8, and cover electric current injection window 9;
One back side n type electrode 11, this back side n type electrode 11 is produced on the back side of n type indium phosphide substrate 1.
Please consult shown in Figure 1ly again, the manufacture method of a kind of single mode F-P of the present invention chamber quantum cascade laser is characterized in that, comprise the steps,
Step 1: adopt the molecular beam epitaxial growth technology, at ducting layer 4, n type top covering 5, n type contact layer 6 and the highly doped ohmic contact layer 7 of n type on the active layer 3 in 2,35 cycles of growing n-type lower waveguide layer, the n type successively on the n type indium phosphide substrate 1;
Step 2: after material has been grown, go out two ditch ridge structures by photoetching, etching process in the surface etch of material, described etching process is to adopt wet etching, corroded n type lower waveguide layer 2 always, obtain dark two ditch ridge structure, this deep etch way can effectively reduce the expansion of injection current, alleviates device heating, the width of the ridge table top of this pair ditch ridge structure is 8-25 μ m, and the width of each ditch is 25-50 μ m;
Step 3: deposit SiO on the table top of two ditch ridge structures 2 Electric insulation layer 8;
Step 4: the SiO on the ridge of two ditch ridge structures 2The place opens electric current and injects window 9 in the middle of the electric insulation layer 8, the size that this electric current injects window 9 be two ditch ridge structures ridge table top tip size 1/3, can guarantee lithography alignment;
Step 5: the SiO of deposit on the table top of two ditch ridge structures 2Make n type positive electrode 10 on the electric insulation layer 8;
Step 6: attenuate n type indium phosphide substrate 1, and in the back side of n type indium phosphide substrate 1 making n type back electrode 11, cleavage, sintering, pressure welding, finally finish the making of entire device, described cleavage is that to obtain the tube core chamber by cleavage long, and the long length in this tube core chamber is less than 145 μ m.
Known that by Fig. 1 this device architecture is dark two ditch ridge structure, this deep etch way can effectively reduce the expansion of injection current, alleviates device heating.
Know that by Fig. 2 for chamber, the F-P chamber quantum laser laser of conventional chamber long (L=1.5mm), device swashs to penetrate composes now a plurality of peak values, shows as multimode operation, wavelength X=5.4 μ m.
We know longitudinal mode spacing Δλ = λ 0 2 2 n e L (λ wherein 0Be excitation wavelength, n eIt is effective refractive index, L is that device cavity is long), because the longitudinal mode spacing of laser can be widened owing to long the reducing in chamber, we just can utilize the way that shortens chamber length to increase longitudinal mode spacing like this, improve the threshold difference of main mould and Bian Mo significantly, and improve the strength ratio of main mould and limit mould effectively by the bell feature of gain spectral curve, finally make device work with a holotype (single mode).
Know the long L=290 μ of this quantum cascade laser device cavity m, Δ λ=14.5nm by Fig. 3, device still shows as a plurality of longitudinal mode work, but with Fig. 2 comparison we as can be seen when chamber length begins to reduce, modulus begins to reduce in the spectrum, and 3 tangible patterns are only arranged among this figure.
Know by Fig. 4, the long L=145 μ of this quantum cascade laser device cavity m, Δ λ=29nm, the long device of this short cavity has shown as single mode operation, and side mode suppression ratio is greater than 20dB, thus proof adopts short bore configurations to realize that single mode operation is a feasible method.
Known that by Fig. 5 the threshold current of the short cavity quantum cascade laser of L=145 μ m only is 80mA, slope efficiency is 0.056W/A, and this proves once more that also short cavity laser can make threshold current significantly reduce.
Example
Please consult Fig. 1 again, the present invention relates to the device architecture of a kind of single mode F-P chamber quantum cascade laser, comprising:
N type indium phosphide substrate 1 is as under-clad layer;
N type indium gallium arsenic lower waveguide layer 2, lower waveguide layer 2 is produced on the n type substrate 1, is used for improving the refractive index of waveguide core layer, strengthens the light restriction;
35 active layers 3 that cycle indium gallium arsenic/indium aluminium arsenic replaces, this active layer 3 is produced on the lower waveguide layer 2, as the luminous zone;
Ducting layer 4 on the n type indium gallium arsenic, ducting layer 4 is produced on the active layer 3 on this, is used for improving the refractive index of waveguide core layer, strengthens the light restriction;
N type indium aluminium arsenic top covering 5, this top covering 5 is produced on the ducting layer 4;
N type indium gallium arsenic high doped contact layer 6, this contact layer 6 is produced on the top covering 5;
N type indium gallium arsenic ohmic contact layer 7, this ohmic contact layer 7 is produced on the N type high doped contact layer 6;
Form two ditch ridged table tops through being etched in the surface, wherein two ditches erode to substrate 1 always, penetrate ducting layer 4, active layer 3 and n type lower waveguide layer 2 on n type ohmic contact layer 7, n type high doped contact layer 6, n type top covering 5, the n type, on this pair ditch ridged table top, be manufactured with SiO 2 Electric insulation layer 8, this electric insulation layer 8 disconnect on ridge and form electric current injection window 9;
Positive n type electrode 10, this front n type electrode 10 is produced on the electric insulation layer 8;
Back side n type electrode 11, this back side n type electrode 11 is produced on the back side of n type indium phosphide substrate 1.
The manufacture method of a kind of novel single mode F-P of the present invention chamber quantum cascade laser comprises the steps:
A1: adopt the molecular beam epitaxial growth technology, growing n-type lower waveguide layer 2 on n type indium phosphide substrate 1, ducting layer 4 and n type top covering 5 on the active layer 3 in 35 cycles of then growing and the n type, last growing n-type contact layer 6 and the highly doped ohmic contact layer 7 of n type;
A2: after material has been grown, etch dark two ditch ridged table top by photoetching, etching process, the width of each ditch is 25-50 μ m, and the width of ridge table top is 8-25 μ m, and two ditches corroded n type lower waveguide layer 2 until n type substrate 1 as shown in Figure 1, is followed deposit SiO 2 Electric insulation layer 8;
A3: the SiO on ridge 2The electric insulation layer place opens electric current and injects window 9, window width is 1/3 of a ridge table top tip size, can guarantee lithography alignment, then on electric insulation layer 8, make n type positive electrode 10, the attenuate epitaxial wafer is made n type back electrode 11 overleaf, and entire device technology is finally finished in cleavage, sintering, pressure welding, wherein the tube core chamber that obtains of cleavage is long, and its length should be less than 145 microns.

Claims (3)

1. the device architecture of a single mode F-P chamber quantum cascade laser is characterized in that, comprising:
One n type indium phosphide substrate is as under-clad layer;
One n type indium gallium arsenic lower waveguide layer, this indium gallium arsenic lower waveguide layer is produced on the n type indium phosphide substrate, is used for improving the refractive index of waveguide core layer, strengthens the light restriction, and this n type indium gallium arsenic lower waveguide layer is a three-stage structure, forms two ditch ridge structures between this three-stage structure;
35 active layers that cycle indium gallium arsenic/indium aluminium arsenic replaces, this active layer is produced on the lower waveguide layer of three-stage structure, as the luminous zone;
Ducting layer on the one n type indium gallium arsenic, ducting layer is produced on the active layer on this indium gallium arsenic, is used for improving the refractive index of waveguide core layer, strengthens the light restriction;
One n type indium aluminium arsenic top covering, this indium aluminium arsenic top covering are produced on the n type indium gallium arsenic on the ducting layer;
One n type indium gallium arsenic high doped contact layer, this n type indium gallium arsenic high doped contact layer is produced on the n type indium aluminium arsenic top covering;
One n type indium gallium arsenic ohmic contact layer, this n type indium gallium arsenic ohmic contact layer is produced on the n type indium gallium arsenic high doped contact layer;
One SiO 2Electric insulation layer, this SiO 2Electric insulation layer is produced on the upper surface of whole material and the sidewall of two ditch ridge structures, this SiO on the ridge of two ditch ridge structures 2The place forms electric current and injects window for disconnecting in the middle of the electric insulation layer;
One positive n type electrode, this front n type electrode is produced on SiO 2On the electric insulation layer, and cover electric current injection window; And
One back side n type electrode, this back side n type electrode is produced on the back side of n type indium phosphide substrate,
Wherein, the chamber length of this laser is less than 145 μ m.
2. the device architecture of single mode F-P according to claim 1 chamber quantum cascade laser is characterized in that, wherein the width of the ridge table top of two ditch ridge structures is 8-25 μ m, and the width of each ditch is 25-50 μ m.
3. the device architecture of single mode F-P according to claim 1 chamber quantum cascade laser is characterized in that, wherein the size of electric current injection window is 1/3 of two ditch ridge structure median ridge table top tip size, can guarantee lithography alignment.
CNB200510126478XA 2005-12-14 2005-12-14 Device structure and its production for single-modulus quantum cascade laser Expired - Fee Related CN100391069C (en)

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US8514902B2 (en) * 2011-03-17 2013-08-20 Corning Incorporated P-type isolation between QCL regions
CN105514801A (en) * 2016-01-20 2016-04-20 中国科学院半导体研究所 Two-groove wide-ridge type semiconductor light amplifier and preparation method thereof
CN105826814A (en) * 2016-05-19 2016-08-03 中国科学院半导体研究所 Method of preparing indium phosphide-based narrow-ridge waveguide semiconductor laser
US10084282B1 (en) 2017-08-14 2018-09-25 The United States Of America As Represented By The Secretary Of The Air Force Fundamental mode operation in broad area quantum cascade lasers
US11031753B1 (en) 2017-11-13 2021-06-08 The Government Of The United States Of America As Represented By The Secretary Of The Air Force Extracting the fundamental mode in broad area quantum cascade lasers
CN108767658B (en) * 2018-07-05 2020-02-21 深圳瑞波光电子有限公司 Manufacturing method of semiconductor laser, semiconductor laser and bar
CN110768106B (en) * 2018-07-26 2021-01-26 山东华光光电子股份有限公司 Laser diode preparation method
CN110007399A (en) * 2019-04-22 2019-07-12 深圳海明光芯科技有限公司 Higher order gratings photoelectric device and its manufacturing method
CN111431033B (en) * 2020-04-10 2021-04-09 中国科学院半导体研究所 Intermediate infrared antimonide quantum cascade laser and preparation method thereof

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