CN207705208U - A kind of infrared avalanche photodide of High Linear gain - Google Patents

A kind of infrared avalanche photodide of High Linear gain Download PDF

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Publication number
CN207705208U
CN207705208U CN201721616000.XU CN201721616000U CN207705208U CN 207705208 U CN207705208 U CN 207705208U CN 201721616000 U CN201721616000 U CN 201721616000U CN 207705208 U CN207705208 U CN 207705208U
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layer
infrared
avalanche photodide
high linear
linear gain
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康健彬
李沫
李倩
王旺平
陈飞良
张健
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Institute of Electronic Engineering of CAEP
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Abstract

The utility model belongs to semiconductor photo detector field, a kind of infrared avalanche photodide of High Linear gain and preparation method thereof is provided, which includes lower contact electrode layer, periodical heterojunction structure dynode layer, charge layer, periodical heterojunction structure absorbed layer and top electrode contact layer.Periodical heterojunction structure absorbed layer realizes that the absorption to infrared photon, periodical heterojunction structure dynode layer promote light induced electron that monopole impact ionization occurs using the distinctive bandgap of GaN/AlN heterojunction materials using sub-band energy level transition in conduction band.Infrared detector provided by the utility model can ensure that device obtains high avalanche gain under linear mode, suitable for the various application scenarios for needing to carry out faint infrared signal detection.

Description

A kind of infrared avalanche photodide of High Linear gain
Technical field
The utility model belongs to semiconductor photo detector field, and in particular to a kind of infrared avalanche optoelectronic of High Linear gain Diode.
Background technology
In the technologies such as long-distance optical fiber communication, quantum secret communication, biomolecule detection, survey of deep space, reach infrared Effective optical signal in the photosensitive member of detector is very faint, and this requires detectors to have high response sensitivity.Compared to Common photodetector, avalanche photodide（Avalanche Photodiode, APD）It can be by multiplier effect Row gain mode detects, and response sensitivity can be highly improved, and is therefore particularly suitable for small-signal even single photon rank Signal detection.
The operation principle of avalanche photodide is carrier makes its ionization under forceful electric power field action with lattice atoms collision New electron-hole pair is generated, to form current multiplication effect.Apply the difference of operating voltage, gain mode according to device Linear gain and Geiger mode angular position digitizer gain can be divided into.Gain is not usually under linear model for traditional body material avalanche photodide More than hundreds of magnitudes, to realize that Detection of Weak Signals just necessarily operates in the Geiger mode angular position digitizer with high-gain, but shortcoming is Need to avoid lasting avalanche process from causing permanent damage to device using more complicated quenching circuit, which limits The application in many fields.By taking long-distance optical fiber communication as an example, the luminous power of the milliwatt order of magnitude is exported from optical sender passes through Only have very faint optical signal after the transmission attenuation of optical fiber to reach at photoreceiver, although using avalanche photodide as Light receiving element can improve signal response intensity, but due to the duration of information transmission, it is only operable on linear model, makes It obtains very limited to the promotion of signal strength.
In order to obtain gain characteristic high under the online sexual norm of device, patent CN106409968 A disclose one kind and are based on Absorption multiplication separate type ultraviolet avalanche probe part of the GaN/AlGaN periodicity heterojunction structure as avalanche region, GaN/AlGaN are different Conduction band Γ energy valley of the big conduction band of matter knot with rank and two kinds of material depths can theoretically ensure electronics in the case of low scattering Efficient dissociative collisions occur, and the dissociative collisions in hole by strong scattering process due to being suppressed simultaneously.This only monopole There is a situation where dissociative collisions similar to the operation principle of photomultiplier for carrier so that avalanche mode becomes controllable, but should Device architecture uptake zone uses AlGaN body materials, is merely able to generate response to ultraviolet light.For in infrared band energy linear model The high-gain avalanche probe part of work nearly no report at present.
Utility model content
The utility model provides a kind of infrared avalanche photodide with High Linear gain, solves infrared at present The avalanche photodide of wave band cannot be the problem of linear model carries out high-gain detection, and the device to work by this method is abandoned Traditional Geiger mode angular position digitizer quenching circuit, greatly expand device can application field.
The technical solution of the utility model is as follows：
The infrared avalanche photodide of High Linear gain, which is characterized in that material structure includes from bottom to top：Substrate delays Layer, lower contact electrode layer, periodical heterojunction structure dynode layer, charge layer, periodical heterojunction structure absorbed layer and top electrode is rushed to connect Contact layer.
The substrate can be Al2O3, any one in the materials such as GaN, AlN, Si, given birth to for material for detector structure It is long.
The buffer layer, lower contact electrode layer, charge layer and top electrode contact layer selected materials are AlxGa1-xN, 0≤x ≤1。
The thickness of the buffer layer is 0.01 μm to 10 μm, the quality for improving growth material.
The N-shaped doping concentration of the lower contact electrode layer is 1 × 1017 cm-3To 5 × 1019 cm-3Between, thickness 0.05 μm to 10 μm, for making N-shaped Ohm contact electrode；
It is 1 to 200, GaN or AlN layers that the periodicity heterojunction structure dynode layer, which uses GaN/AlN material structures, periodicity, Thickness be 0.001 μm to 0.2 μm, for carrier occur monopole impact ionization region；
The p-type doping concentration of the charge layer is 1 × 1017 cm-3To 1 × 1019 cm-3Between, thickness be 0.01 μm extremely 0.15 μm, it is used for the adjusting of absorbed layer and dynode layer electric field；
The periodicity heterojunction structure absorbed layer uses AlyGa1-yN/AlzGa1-zN materials system, wherein 0≤y<Z≤1 is formed The Quantum Well or superlattice structure, transition of the electronics from conduction band ground state level to excited level that periodicity is 1 to 200 correspond to The absorption of infrared photon.AlyGa1-yN material N-shapeds adulterate, and doping concentration is 5 × 1017cm-3To 5 × 1019 cm-3Between, thickness It is 0.001 μm to 0.02 μm, AlyGa1-yN thickness is 0.001 μm to 0.1 μm；
The top electrode contact layer p-type doping concentration is 1 × 1017 cm-3To 1 × 1019 cm-3Between, thickness is 0.05 μ M to 0.2 μm, for making p-type Ohm contact electrode.
The method for preparing the utility model, its step are as follows：
（1）Grown buffer layer on substrate；
（2）Lower contact electrode layer is grown on the buffer layer, makes N-shaped Ohm contact electrode above；
（3）The growth periodicity heterojunction structure dynode layer on lower contact electrode layer；
（4）Charge layer is grown on dynode layer；
（5）The growth periodicity heterojunction structure absorbed layer on charge layer；
（6）Top electrode contact layer is grown on absorbed layer, makes p-type Ohmic electrode above；
（7）According to the selective rule of sub-band transition, device substrate one side bevel after completing or One-dimensional grating or two-dimensional grating are made on top electrode contact layer to realize the coupling to infrared light.
Based on above technical solution, the usefulness of the utility model is to absorb the separate type avalanche probe part that doubles It is middle that uptake zone and multiplication region are disposed as periodical heterojunction material, to realize that the High Linear gain mode in infrared band is visited It surveys.The utility model proposes one allow for GaN/AlN hetero-junctions and can increase substantially electrons and holes as avalanche region Ionization coefficient ratio, you can think that only electronics can just collide ionization, this unidirectional multiplicative process enables device The work of enough high-gains under linear model, saturation gain size are related with the parameter of heterojunction material and periodicity；Secondly Allow for AlyGa1-yN/AlzGa1-zThe conduction band band rank of N heterojunction materials is continuously adjustable from 0-2 eV, thus its sub-band transition Absorbing wavelength can cover optic communication near infrared band of interest even in, far infrared band, and the current-carrying of sub-band transition The sub- service life only has picosecond magnitude, theoretically has the response speed being exceedingly fast to incoming signal；On the other hand from the point of view of material system, Uptake zone and multiplication region belong to AlGaN sills, and the compatibility on material can ensure the smooth implementation of epitaxial process.Therefore By rationally designing uptake zone conduction band quantum level of energy and multiplication region band structure, while utilizing sub-band energy level transition and photoproduction The High Linear gain mode detection of distinctive infra-red bands then can be achieved in the efficient monopole impact ionization of electronics.
To further illustrate the feature and effect of the utility model, below in conjunction with the accompanying drawings and specific embodiment is new to this practicality Type is described further.
Description of the drawings
Fig. 1 is band structure schematic diagram and carrier of the utility model avalanche photodide under working inverse voltage Transport schematic diagram.
Fig. 2 is the cross section structure schematic diagram I of avalanche photodide in embodiment.
Fig. 3 is the cross section structure schematic diagram II of avalanche photodide in embodiment.
Fig. 4 is the conduction band band structure and electron waves of the periodical heterojunction structure absorbed layer of embodiment avalanche photodide Function is distributed.
Fig. 5 is the periodical heterojunction structure dynode layer of embodiment avalanche photodide under 1 MV/cm electric field actions Band structure schematic diagram.
Wherein, contact electrode layer under 101-n types, 103- periodicity heterojunction structure dynode layers, 105- charge layers, 107- Periodical heterojunction structure absorbed layer, 109-p type top electrode contact layers, 201- substrates, 203- buffer layers, 205-n type ohms Contact electrode, 207-p type Ohm contact electrodes, 301- optical grating constructions, the distribution of the uptake zones 401- conduction band, 403- absorbed layer electricity Sub- ground state level wave function, 405- absorbed layer excited electronic state energy level wave functions, the distribution of 501- multiplication region conduction bands, 503- times Increase the distribution of area's valence band.
Specific implementation mode
In order to more clearly show that the operation principle of the utility model device, Fig. 1 give device in working inverse voltage Under band structure and carrier dynamics process.Contact electrode layer and p-type top electrode under N-shaped are needed under device working condition Apply larger reverse biased between contact layer, at this moment potential difference is mainly loaded into undoped periodical heterojunction structure dynode layer On, the electric field strength of this layer is much larger than the electric field strength of other each layers, shows as the wide-angle tilt of energy band.It can be seen that simultaneously Since charge layer is to the regulating and controlling effect of electric field, the energy band of periodical heterojunction structure absorbed layer is substantially at flat rubber belting state, to ensure Electronics in ground state level will not be depleted, and have enough electronics fillings.
When there is infrared light incidence, electron transition in periodical heterojunction structure absorbed layer ground state level to excited level As light induced electron, light induced electron directly migrates to charge layer by resonance tunnel-through or in continuous state, is then transported to week again Collide ionization in phase property heterojunction structure dynode layer.Dynode layer uses GaN/AlN material structures, conduction band band rank to reach 2 EV, and Valence-band Offsets only have about 0.8 eV.Light induced electron first accelerates at AlN layers and obtains certain energy, returns GaN layer Potential energy is discharged when middle, the gross energy that at this moment electronics obtains will be greater than the energy gap of GaN material, it is possible thereby to efficiently triggering electricity Sub- impact ionization.For hole, the valence band higher density of states is largely scattered when it being made to accelerate at AlN layers, and smaller valence Also very limited with the potential energy provided with rank, dissociative collisions are almost totally constrained.Device detects the wavelength of infrared light by week The energy difference of phase property heterojunction structure absorbed layer ground state level and excited level determine, and the relative position of energy level be substantially by The structural parameters of material（Thickness, Al components such as potential well/barrier layer）It determines, therefore can by the material parameter of reasonable absorbed layer Realize the response regulation near infrared band to far infrared band.
Fig. 2 and Fig. 3 show the schematic cross-section of device architecture described in this example, and difference lies in directs for the two The coupled modes of light are different.Since there is sub-band transition polarization selectivity, i.e. incident infrared light to have perpendicular to epitaxial growth The electric field component of plane, therefore cannot directly absorb the light wave of vertical incidence.Fig. 2 will be made by the way of side surface coupling The one side of device wears into certain angle of inclination after the completion of work, and infrared light is incident from the inclined-plane.Fig. 3 is using grating coupled Mode, is produced and lambda1-wavelength is matched one-dimensional or two-dimensional grating structure on top electrode contact layer, and infrared light is from upper table Face vertical incidence.
The structure uses molecular beam epitaxy technique（MBE）Or metal organic chemical compound vapor deposition technology（MOCVD）In indigo plant Jewel Grown, Material growth and device preparation flow are as follows：
（1）2 μm of AlN buffer layers are first grown on a sapphire substrate；
（2）Contact electrode layer under the N-shaped GaN of 500nm is then grown on AlN buffer layers, doping concentration is 5 × 1018 cm-3；
（3）10 period GaN of regrowth on contact electrode layer at N-shaped GaN（20nm）/AlN（20nm）Heterojunction structure times Increasing layer, two kinds of material alternating growths simultaneously keep strict periodicity；
（4）The p-type GaN charge layers of 20nm are grown on dynode layer, p-type doping concentration is 1 × 1018cm-3；
（5）40 period GaN are grown on p-type GaN charge layers（1.5nm）/AlN（1.5nm）Heterojunction structure absorbed layer, GaN layer N-shaped adulterates, and doping concentration is 1 × 1019 cm-3；
（6）The p-type GaN top electrode contact layers of regrowth 100nm on absorbed layer, doping concentration are 1 × 1019cm-3；
（7）Epitaxial wafer after the completion of growth 600 DEG C of high annealing half an hour in air atmosphere are adulterated miscellaneous with activating a p-type Matter；
（8）According to coupling infra-red light structure shown in Fig. 3, then first holographic exposure techniques and ICP lithographic techniques is used to exist Produce one-dimensional or two-dimensional grating structure in epitaxial wafer surface；
（9）The subregion of material sample electrode under N-shaped GaN is etched to using photoetching process and ICP etching technics to connect Contact layer forms a diameter of some tens of pm to the circle or square-shaped mesa structure of hundreds of microns；
（10）Use electron beam evaporation technique on mesa structure deposition thickness for the transparent electricity of the Ni/Au of 2.5nm/5nm The tin indium oxide of pole or 200 nm（ITO）Transparent electrode, the surfaces N-shaped GaN then exposed after etching are using the method sputtered Deposition thickness is the Ti/Au electrodes of 20 nm/300 nm；
（11）Make the 500 DEG C of annealing 3min in oxygen atmosphere of the sample after electrode；
（12）Using plasma chemical vapour deposition technique again（PECVD）300nmSiO is deposited in sample surfaces2Or SiNx Passivation protection layer, using reactive ion etching（RIE）Technology etches away the passivation protection layer on metal electrode；
（13）According to coupling infra-red light structure shown in Fig. 2, then also need the bottom surface side sand paper mill by substrate at 45 ° Angle.
Fig. 4 show the periodical heterojunction structure absorbed layer being calculated（Only provide 5 periods）Conduction band schematic diagram and electricity Wavelet function is distributed.According to result of calculation, the energy difference of ground state level and excited level is about under the material structure parameter 0.81 eV, it is meant that response will be generated to the near infrared light of 1.53 μm of peak wavelength, which corresponds exactly to optic communication institute The wave band of concern.As can be seen from the figure excited level wave function has stronger mutual between each Quantum Well of absorbed layer Coupling, contributes to light induced electron efficiently to move in dynode layer.
Fig. 5 show band structure of the periodical heterojunction structure dynode layer of emulation under 1 MV/cm electric fields, in highfield Under the action of energy band integrally tilted.In no extra electric field or DC Electric Field very little, GaN potential well layers and AlN Since the polarity effect of itself leads to direction of an electric field on the contrary, as shown in conduction band in Fig. 4 in barrier layer, but the gesture under forceful electric power field action The direction of an electric field of well layer and barrier layer becomes to reach unanimity, and at this moment polarity effect present in AlN barrier layers helps to increase and carry Sub- kinetic energy is flowed, this is helpful for the avalanche voltage for reducing device.Description according to front to device operation principle, light induced electron Primary collision ionization can occur when entering GaN potential wells from AlN barrier layers every time, then the number of electron collision ionization with it is different The periodicity of matter structure is related, and there are about 2 in the GaN/AlN structural theories in ten periods in embodiment10Secondary impact ionization, i.e. device Saturation gain is 103Magnitude.

Claims (8)

1. a kind of infrared avalanche photodide of High Linear gain, which is characterized in that the material structure of the diode from down toward On include：Substrate, buffer layer, lower contact electrode layer, periodical heterojunction structure dynode layer, charge layer, periodical heterojunction structure are inhaled Receive layer and top electrode contact layer；The buffer layer, lower contact electrode layer, charge layer and top electrode contact layer selected materials are AlxGa1-xN, 0≤x≤1.
2. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The substrate is Al2O3, any one in GaN, AlN, Si.
3. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The buffer layer Thickness is 0.01 μm to 10 μm.
4. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The lower electrode connects The N-shaped doping concentration of contact layer is 1 × 1017 cm-3To 5 × 1019 cm-3Between, thickness is 0.05 μm to 10 μm.
5. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The periodicity is different Matter structure dynode layer is formed by two kinds of material alternating growths of GaN and AlN, forms the heterojunction structure that periodicity is 1 to 200；It is described The thickness of GaN or AlN is 0.001 μm to 0.2 μm.
6. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The charge layer P-type doping concentration is 1 × 1017 cm-3To 1 × 1019 cm-3Between, thickness is 0.01 μm to 0.15 μm.
7. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The periodicity is different Matter structure absorbing layer by two kinds of different components AlyGa1-yN and AlzGa1-zN material alternating growths form, formed periodicity be 1 to 200 Quantum Well or superlattice structure, wherein 0≤y<z≤1；The AlyGa1-yN potential well N-shapeds adulterate, doping concentration 5 × 1017cm-3To 5 × 1019 cm-3Between, thickness is 0.001 μm to 0.02 μm；The AlyGa1-yN potential barrier thickness is 0.001 μ M to 0.1 μm.
8. the infrared avalanche photodide of High Linear gain according to claim 1, it is characterised in that：The top electrode connects Contact layer p-type doping concentration is 1 × 1017 cm-3To 1 × 1019 cm-3Between, thickness is 0.05 μm to 0.2 μm.
CN201721616000.XU 2017-11-28 2017-11-28 A kind of infrared avalanche photodide of High Linear gain Expired - Fee Related CN207705208U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107863403A (en) * 2017-11-28 2018-03-30 中国工程物理研究院电子工程研究所 A kind of infrared avalanche photodide of High Linear gain and preparation method thereof
CN109037385A (en) * 2018-08-09 2018-12-18 镇江镓芯光电科技有限公司 A kind of ultraviolet avalanche photodiode
CN113299785A (en) * 2021-04-06 2021-08-24 中国科学院微电子研究所 Silicon-based detector and manufacturing method thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107863403A (en) * 2017-11-28 2018-03-30 中国工程物理研究院电子工程研究所 A kind of infrared avalanche photodide of High Linear gain and preparation method thereof
CN107863403B (en) * 2017-11-28 2023-10-20 中国工程物理研究院电子工程研究所 High-linear gain infrared avalanche photodiode and preparation method thereof
CN109037385A (en) * 2018-08-09 2018-12-18 镇江镓芯光电科技有限公司 A kind of ultraviolet avalanche photodiode
CN113299785A (en) * 2021-04-06 2021-08-24 中国科学院微电子研究所 Silicon-based detector and manufacturing method thereof

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