CN207021269U

CN207021269U - A kind of PIN structural UV photodetector

Info

Publication number: CN207021269U
Application number: CN201720479083.6U
Authority: CN
Inventors: 王书昶; 刘玉申; 李中国; 冯金福
Original assignee: Changshu Institute of Technology
Current assignee: Changshu Institute of Technology
Priority date: 2017-05-02
Filing date: 2017-05-02
Publication date: 2018-02-16
Anticipated expiration: 2027-05-02

Abstract

The utility model discloses a kind of PIN structural UV photodetector, including set gradually from the bottom to top Sapphire Substrate, AlN nucleating layers, Al_x1Ga_1‑x1N cushions, n-type Al_x2Ga_1‑x2N layers, undoped i types ZnO/TiO₂Superlattices absorbed layer, p-type Al_x3Ga_1‑x3N layers, p-type GaN layer, in n-type Al_x2Ga_1‑x2The n-type Ohmic electrode drawn on N layers, the p-type Ohmic electrode drawn in p-type GaN layer, the undoped i types ZnO/TiO₂In superlattices absorbed layer, the repetition period number of superlattices is 1~10.The invention also discloses the preparation method of PIN structural UV photodetector.The PIN structural UV photodetector can improve responsiveness of the detector to weak UV signal.

Description

A kind of PIN structural UV photodetector

Technical field

A kind of UV photodetector is the utility model is related to, more particularly, to a kind of PIN structural UV photodetector, Belong to semiconductor photoelectronic device field.

Background technology

UV photodetector all has important application value and development prospect at dual-use aspect, such as：It is ultraviolet Alarm is with guiding, the detecting of hydrocarbon combustion flame, the detection of biochemical gene, ultraviolet astronomy are studied, short-range Communication and treating for skin disease etc..PIN structural UV photodetector has small volume, in light weight, long lifespan, shock resistance It is good, operating voltage is low, high temperature resistant, corrosion-resistant, Flouride-resistani acid phesphatase, quantum efficiency are high and the advantages that without optical filter, it has also become photoelectricity is visited The study hotspot in survey field.

Gallium nitride-based semiconductor ternary compound Al_xGa_1-xThe band gap of N materials can be adjusted by changing Al components x Section, make to absorb optical wavelength corresponding to it between 200~365nm, covering is caused because ozone layer absorbs ultraviolet light just Solar spectrum blind area (220~290nm).ZnO is a kind of direct band gap semiconductor material with wide forbidden band.ZnO no matter lattice structure, Cell parameter is still all similar to GaN material in energy gap, and has the fusing point higher than GaN and bigger exciton confinement Can, there is relatively low luminescence generated by light and threshold value and good electromechanical coupling characteristics, the heat endurance and chemistry of stimulated radiation again Stability.Due to ZnO and TiO₂The advantages of material itself, fabulous ultraviolet detection performance is presented, its photocurrent gain is reachable To 105, and it has the advantages that operating voltage is relatively low, energy consumption is smaller, small volume, in light weight, turns into ultraviolet spy in recent years Survey the focus of research.

But due to prior art prepare AlGaN material film quality it is not high, AlGaN material with surface deposition When metal forms schottky junction there is the defects of a large amount of in interface so that active area is thinning, and tunnel mechanism is obvious, causes dark current very Greatly, the raising of the detection performance of such feature detector thus is seriously constrained.

Utility model content

The defects of for prior art, the utility model provide a kind of PIN structural UV photodetector, solve Ultraviolet detector is insensitive caused by electronics and the ionization coefficient similar in hole in AlGaN base ultraviolet light electric explorers, The problem of to the responsiveness difference of weak UV signal.

Technical solutions of the utility model are as follows：A kind of PIN structural UV photodetector, including set gradually from the bottom to top Sapphire Substrate, AlN nucleating layers, Al_x1Ga_1-x1N cushions, n-type Al_x2Ga_1-x2N layers, undoped i types ZnO/TiO₂Superlattices Absorbed layer, p-type Al_x3Ga_1-x3N layers, p-type GaN layer, in n-type Al_x2Ga_1-x2The n-type Ohmic electrode drawn on N layers, in p-type GaN layer The p-type Ohmic electrode of upper extraction, the undoped i types ZnO/TiO₂In superlattices absorbed layer, the repetition period number of superlattices is 1 ~10.

Preferably, the AlN nucleating layers thickness is 20~60nm, the Al_x1Ga_1-x1N buffer layer thicknesses be 200~ 800nm, the n-type Al_x2Ga_1-x2N thickness degree is 500~1000nm, the undoped i types ZnO/TiO₂Superlattices absorb thickness Spend for 100~200nm, the p-type Al_x3Ga_1-x3N thickness degree is 50~100nm, the p-type GaN layer thickness is 100~ 200nm。

Preferably, the undoped i types ZnO/TiO₂In superlattices absorbed layer, in the monocycle ZnO layer thickness be 5~ 10nm, TiO₂Thickness degree is 5~10nm.

Preferably, the n-type Ohmic electrode is Ti/Al/Ti/Au alloy electrodes, and p-type Ohmic electrode is Ni/Au alloys electricity Pole.

Preferably, the Sapphire Substrate is C faceted crystals.

The advantages of technical scheme provided by the utility model, is：Due to the undoped i types of multicycle superlattice structure ZnO/TiO₂The high absorption coefficient of material, high horizontal carrier transport factor and strong polarity effect, the electricity of absorbed layer can be effectively increased , therefore the quantum efficiency of ultraviolet detector can be improved.Can also effectively solve in UV photodetector due to electronics and Ultraviolet detector is insensitive caused by the ionization coefficient similar in hole, is favorably improved response of the detector to weak UV signal Degree.

Brief description of the drawings

Fig. 1 is the utility model structure diagram.

Embodiment

With reference to embodiment, the utility model is described in further detail, but not as to restriction of the present utility model.

Embodiment 1, as shown in figure 1, the PIN structural UV photodetector involved by the present embodiment, including from the bottom to top Set gradually the Sapphire Substrates 101 of C faceted crystals, AlN nucleating layers 102, Al_x1Ga_1-x1N cushions 103, n-type Al_x2Ga_1-x2N layers 104th, undoped i types ZnO/TiO₂Superlattices absorbed layer 105, p-type Al_x3Ga_1-x3N layers 106, p-type GaN layer 107, in n-type Al_x2Ga_1-x2The n-type Ohmic electrode 109 drawn on N layers 104, the p-type Ohmic electrode 108 drawn in p-type GaN layer 107.Wherein The thickness of AlN nucleating layers 102 is 25nm, and the specific layer thickness value that is nucleated can adjust according to being actually needed.Al_x1Ga_1-x1N cushions 103 thickness is 400nm, and x1=0.30 therein.N-type Al_x2Ga_1-x2The thickness of N layers 104 is 700nm, and therein X2=0.45, it is doped using Si, wherein Si doping concentration is more than 5 × 10¹⁸cm^-3.Undoped i types ZnO/TiO₂Superlattices Absorbed layer 105, ZnO layer thickness is 5nm, TiO in the monocycle₂Thickness degree is 10nm, and repetition period number is 10.P-type Al_x3Ga_1-x3The thickness of N layers 106 is 60nm, and the Mg of use is doped, and doping concentration is 5 × 10¹⁷cm^-3, wherein subscript X3=0.6, i.e. p-type Al_x3Ga_1-x3The energy gap of N layers 106 is more than n-type Al_x2Ga_1-x2The energy gap of N layers 104.P-type GaN layer 107 thickness is 200nm, and doping concentration therein is 5 × 10¹⁸cm^-3.P-type Ohmic electrode 108 is Ti/Al/Ti/Au alloys electricity Pole, n-type Ohmic electrode 109 are Ni/Au alloy electrodes.

The preparation method of the PIN structural UV photodetector is：

(1) the growing AIN nucleating layer 102 in the Sapphire Substrate 101 of C faceted crystals；

(2) one layer of Al is grown on AlN nucleating layers 102_x1Ga_1-x1N cushions 103；

(3) in Al_x1Ga_1-x1One layer of n-type Al is grown on N cushions 103_x2Ga_1-x2N layers 104；

(4) in n-type Al_x2Ga_1-x2One layer of undoped i type is grown using mocvd method on N layers 104 ZnO/TiO₂Superlattices absorbed layer 105；

(5) in undoped i types ZnO/TiO₂One layer of p-type Al is grown on superlattices absorbed layer 105_x3Ga_1-x3N layers 106；

(6) in p-type Al_x3Ga_1-x3One layer of p-type GaN layer 107 is grown on N layers 106；

(7) photoetching is carried out in 107 enterprising row of p-type GaN layer, etches electrode table top, expose n-type Al_x2Ga_1-x2N layers 104, Table top after etching is handled；

(8) it is deposited p-type Ohmic electrode 108 in p-type GaN layer 107, electrode is Ti/Al/Ti/Au alloy electrodes, after evaporation In 600 DEG C of N₂Annealed 3 minutes under environment；

(9) in n-type Al_x2Ga_1-x2Evaporating n type Ohmic electrode 109 on the table top of N layers 104, electrode are Ni/Au alloy electrodes, electricity Pole size is 0.3 × 0.3mm², in 850 DEG C of N after evaporation₂Annealed 2 minutes under environment.

The preparation-obtained ultraviolet detector of the present embodiment, it can greatly strengthen the responsiveness to weak UV signal, especially It embodies advantage in terms of single photon detection.According to measuring and calculating, when the peak response wavelength of device is 280nm, device is in zero bias The dark current of pressure is nA magnitudes, and peak response degree is 9.4mA/W；For device under -10V biass, peak response degree is 40.7mA/ W, corresponding external quantum efficiency can reach 30%.

Embodiment 2, as shown in figure 1, the PIN structural UV photodetector involved by the present embodiment, including from the bottom to top Set gradually the Sapphire Substrates 101 of C faceted crystals, AlN nucleating layers 102, Al_x1Ga_1-x1N cushions 103, n-type Al_x2Ga_1-x2N layers 104th, undoped i types ZnO/TiO₂Superlattices absorbed layer 105, p-type Al_x3Ga_1-x3N layers 106, p-type GaN layer 107, in n-type Al_x2Ga_1-x2The n-type Ohmic electrode 109 drawn on N layers 104, the p-type Ohmic electrode 108 drawn in p-type GaN layer 107.Wherein The thickness of AlN nucleating layers 102 is 20nm.Al_x1Ga_1-x1The thickness of N cushions 103 is 300nm, and x1=0.45 therein.n Type Al_x2Ga_1-x2The thickness of N layers 104 is 500nm, and x2=0.55 therein, is doped using Si, wherein Si doping Concentration is more than 5 × 10¹⁸cm^-3.Undoped i types ZnO/TiO₂Superlattices absorbed layer 105, ZnO layer thickness is 10nm in the monocycle, TiO₂Thickness degree is 10nm, and repetition period number is 5.P-type Al_x3Ga_1-x3The thickness of N layers 106 is 50nm, and the Mg of use is mixed It is miscellaneous, and doping concentration is 5 × 10¹⁶cm^-3, wherein subscript x3=0.7, i.e. p-type Al_x3Ga_1-x3The energy gap of N layers 106 is more than N-type Al_x2Ga_1-x2The energy gap of N layers 104.The thickness of p-type GaN layer 107 is 100nm, doping concentration therein is 5 × 10¹⁸cm^-3.P-type Ohmic electrode 108 is Ti/Al/Ti/Au alloy electrodes, and n-type Ohmic electrode 109 is Ni/Au alloy electrodes.Should The preparation method of PIN structural UV photodetector is the same as embodiment 1.

The preparation-obtained ultraviolet detector of the present embodiment, according to measuring and calculating, when the peak response wavelength of device is 280nm When, dark current of the device under zero-bias is nA magnitudes, and peak response degree is 7.9mA/W；Under -10V biass, peak value rings device Response is 52.4mA/W, and corresponding external quantum efficiency can reach 35%.

Embodiment 3, as shown in figure 1, the PIN structural UV photodetector involved by the present embodiment, including from the bottom to top Set gradually the Sapphire Substrates 101 of C faceted crystals, AlN nucleating layers 102, Al_x1Ga_1-x1N cushions 103, n-type Al_x2Ga_1-x2N layers 104th, undoped i types ZnO/TiO₂Superlattices absorbed layer 105, p-type Al_x3Ga_1-x3N layers 106, p-type GaN layer 107, in n-type Al_x2Ga_1-x2The n-type Ohmic electrode 109 drawn on N layers 104, the p-type Ohmic electrode 108 drawn in p-type GaN layer 107.Wherein The thickness of AlN nucleating layers 102 is 60nm.Al_x1Ga_1-x1The thickness of N cushions 103 is 800nm, and x1=0.4 therein.n Type Al_x2Ga_1-x2The thickness of N layers 104 is 1000nm, and x2=0.6 therein, is doped using Si, wherein Si doping Concentration is more than 5 × 10¹⁸cm^-3.Undoped i types ZnO/TiO₂Superlattices absorbed layer 105, ZnO layer thickness is 10nm in the monocycle, TiO₂Thickness degree is 10nm, and repetition period number is 1.P-type Al_x3Ga_1-x3The thickness of N layers 106 is 100nm, and the Mg of use is carried out Doping, and doping concentration is 5 × 10¹⁸cm^-3, wherein subscript x3=0.8, i.e. p-type Al_x3Ga_1-x3The energy gap of N layers 106 is big In n-type Al_x2Ga_1-x2The energy gap of N layers 104.The thickness of p-type GaN layer 107 is 150nm, doping concentration therein is 5 × 10¹⁸cm^-3.P-type Ohmic electrode 108 is Ti/Al/Ti/Au alloy electrodes, and n-type Ohmic electrode 109 is Ni/Au alloy electrodes.Should The preparation method of PIN structural UV photodetector is the same as embodiment 1.

The preparation-obtained ultraviolet detector of the present embodiment, according to measuring and calculating, when the peak response wavelength of device is 280nm When, dark current of the device under zero-bias is nA magnitudes, and peak response degree is 11.8mA/W；Device is under -10V biass, peak value Responsiveness is 38.4mA/W, and corresponding external quantum efficiency can reach 28%.

It must be noted that:The utility model is applicable not only to the ultraviolet snowslide of metal mold gallium nitride base of metal-semiconductor one Photodetector, it is equally applicable for Schottky barrier type gallium nitride base ultraviolet avalanche photodetector.

Claims

A kind of 1. PIN structural UV photodetector, it is characterised in that including set gradually from the bottom to top Sapphire Substrate, AlN nucleating layers, Al_x1Ga_1-x1N cushions, n-type Al_x2Ga_1-x2N layers, undoped i types ZnO/TiO₂Superlattices absorbed layer, p-type Al_x3Ga_1-x3N layers, p-type GaN layer, in n-type Al_x2Ga_1-x2The n-type Ohmic electrode drawn on N layers, the p drawn in p-type GaN layer Type Ohmic electrode, the undoped i types ZnO/TiO₂In superlattices absorbed layer, the repetition period number of superlattices is 1~10.
2. PIN structural UV photodetector according to claim 1, it is characterised in that the AlN nucleating layers thickness is 20~60nm, the Al_x1Ga_1-x1N buffer layer thicknesses are 200~800nm, the n-type Al_x2Ga_1-x2N thickness degree be 500~ 1000nm, the undoped i types ZnO/TiO₂Superlattices absorber thickness is 100~200nm, the p-type Al_x3Ga_1-x3N thickness It is 100~200nm to spend for 50~100nm, the p-type GaN layer thickness.
3. PIN structural UV photodetector according to claim 1, it is characterised in that the undoped i types ZnO/ TiO₂In superlattices absorbed layer, ZnO layer thickness is 5~10nm, TiO in the monocycle₂Thickness degree is 5~10nm.
4. PIN structural UV photodetector according to claim 1, it is characterised in that the n-type Ohmic electrode is Ti/Al/Ti/Au alloy electrodes, p-type Ohmic electrode are Ni/Au alloy electrodes.
5. PIN structural UV photodetector according to claim 1, it is characterised in that the Sapphire Substrate is C faces Crystal.