CN103276356A - Method for improving heat stability of Cu3N thin film - Google Patents

Abstract

The invention discloses a method for improving heat stability of a Cu3N thin film. The method comprises the following steps of: 1, sequentially carrying out ultrasonic-cleaning on an Si(100) substrate for depositing a sample by cleanser essence, acetone, anhydrous alcohol and deionized water for 15 minutes for later use; 2, placing a doped material on a Cu target, and then, placing the substrate on a sample stand which is parallel to the surface of the target and 50-60mm away from the surface of the target; 3, ensuring that the target is not grounded; 4, carrying out corrosion of HF (Hydrofluoric acid) with the concentration of 1% on the Si(100) substrate for 1-2 minutes, washing with plasma water after HF acid treatment, and then airing and placing the substrate on the sample stand; 5, closing a vacuum chamber and vacuumizing; and 6, introducing pure nitrogen to the vacuum chamber and co-sputtering the target and the doped material in the conditions of low temperature and low power. The heat stability of the Cu3N thin film is improved by co-sputtering the target and the doped material.

Description

A kind of raising Cu 3The method of N film heat stability

Technical field

The invention belongs to the semiconductor film preparation field, particularly relate to a kind of raising Cu ₃The method of N film heat stability.

Background technology

Has anti-ReO ₃Cuprous nitride (the Cu of structure, low decomposition temperature ₃N) semiconductor material has very bright application prospect aspect optical information storage and the large-scale integrated circuit ^[1-3]Recently, this material fields such as also can be used for spin electric device, solar cell, fuel cell, magnetic tunnel-junction that is in the news ^[1,4-9], thereby this system is extensively paid close attention in the world.How Cu ₃It is present Cu that the suitable temperature that the heat decomposition temperature of N improves is used it better ₃One of focus that the N research field is paid close attention to.

The method that improves heat decomposition temperature has two kinds, and one, change growth conditions, the Cu of growing high-quality, desirable stoicheiometry ₃The N film; Two, because Cu ₃N is a kind of anti-ReO that has ₃The similar WO of crystalline structure ₃Inorganic matrix material, add atom (Ni, Cu, Zn, Pd, Ag, and Cd) occupy-place at a cube anti-ReO ₃Cu is modified in the position, body-centered of structure cell therefore by mixing ₃The energy band structure of N can realize Cu ₃Characteristics such as N thermostability or even electricity, optics adjustable on a large scale.For the former, desirable stoicheiometry Cu grows ₃The technology of N film is comparatively ripe.For Cu ₃The doping of N experimentally has some reports at present, but Cu ₃The doping of N film is the process of a complexity, and foreign atom is mixed to where whether being in anti-ReO ₃The kind of position, the body-centered foreign atom of crystalline structure is to Cu ₃The rerum natura of N film have how to influence the doping film characteristic with the dependence of doped element content as how all remaining further research.

Reference:

[1]?Asano?M,?Umeda?K?and?Tasaki?A?1990?Jpn.?J.?Appl.?Phys.? 29?1985

[2]?Maruyama?T?and?Morishita?T?1996?Appl?Phys.?Lett. ?69?890

[3]?Nosaka?T,?Yoshitake?M,?Okamoto?A,?Ogawa?S?and?Nakayama?Y?2001?Appl.?Surf.?Sci.? 169?358

[4]?Maya?L?1993?Mater.?Res.?Soc.?Symp.?Proc? 282?203

[5]?Maya?L?1993?J.?Vac.?Sci.?Technol.? A11?604

[6]?Cremer?R,?Witthaut?M,?Neuschutz?D,?Trappe?C,?Laurenzis?M,?Winkle?O?and?Kurz?H?2000?Mikrochim.?Acta? 133?299

[7]?Navio?C,?Alvarez?J,?Capitan?M?J,?Camarero?J?and?Miranda?R?2009?Appl.?Phys.?Lett.? 94?263112

[8]?Navio?C,?Capitan?M?J,?Alvarez?J,?Yndurain?F?and?R.?Miranda?2007?Phys?Rev?B? 76?085105

[9]?Borsa?D?M,?Grachev?S,?Presura?C?and?Boerma?D?O?2002?Appl.?Phys.?Lett.? 80?1823

Summary of the invention

The technical solution adopted for the present invention to solve the technical problems specifically comprises the steps:

Step 1. will be used each ultrasonic cleaning of liquid detergent, acetone, raw spirit and deionized water 15 minutes successively for Si (100) substrate of deposited samples, and will be stand-by.

Step 2. will be with dopant material to place on the Cu target, then substrate will be placed on the specimen holder, and specimen holder and target surface is parallel and at a distance of 50-60 mm.

Step 3. detects whether ground connection of target, if ground connection then reapposes, guarantees that target is earth-free.

Step 4. need be carried out the HF acid corrosion of 1% concentration with Si (100) substrate, and the treatment time is 1-2min, with the plasma water flushing, dries up then and places specimen holder after the HF acid treatment.

Step 5. is closed vacuum chamber, vacuumizes.

Step 6. background air pressure in vacuum chamber is lower than 6 * 10 ^-6During mbar, feed pure nitrogen gas (99.99%) in vacuum chamber, cosputtering target and dopant material under the lower powered condition of low temperature are by changing area coverage, the covering position of dopant material on target, at the Cu of the synthetic different components ratio of substrate ₃NM _xFilm.

The Cu that step 7. is prepared ₃NM _xFilm need carry out the electrology characteristic test of thermal decomposition product, guarantees that thermal decomposition product is good conductor.

The material of described cosputtering is In, Ti.

The present invention realizes Cu by cosputtering dopant material and target ₃The raising of N film heat stability, cosputtering carries out under low temperature, subatmospheric and lower powered condition, and the material of cosputtering can be In, Ti etc.

Selecting In to mix, mainly is because InN has the higher decomposition temperature～873K that compares and it is contemplated that, if to Cu ₃N carries out In and mixes, and the film of generation has possibly and has some novel characteristics at aspects such as structure, electricity, optics, and can still keep characteristic of semiconductor when rationally improving decomposition temperature.Like this, envrionment temperature when film both can bear most electron device and prepares, keep the stability under the high temperature, can allow again with local heating mode (the electron beams bundle scans fast) with lower, existing device architecture is not caused the micro-nano metal construction of the temperature acquisition satisfactory electrical conductivity of damage.

Select Ti to mix, the advantage that Ti mixes is that the nitride fusing point of titanium is all very high, and this just makes

The Cu that Ti mixes ₃The N film may have higher decomposition temperature, and again because the nitride of titanium all is good conductor, even so have the separation phase of titanium nitride in the laminated film, can not influence the metallic conductivity of degradation production and high reflectivity yet.So if the cuprous nitride film of mixing on a small quantity behind the titanium still keeps characteristic of semiconductor, it just still can be used for optical information storage and unicircuit probably.

Beneficial effect of the present invention is as follows:

Present method has remedied the deficiencies in the prior art, has improved Cu ₃The thermostability of N film.

Description of drawings

Fig. 1 Cu _xIn _yThe XRD spectrum of N film, the In content of counter sample is 8.2at.%:(a) primary sample, (b) 330 ℃ of annealing, (c) 360 ℃ of annealing;

Fig. 2 titanium content is the XRD spectrum of film under differing temps of 2.2at.%: (a) primary sample, (b) 350 ℃ of annealing, (c) 400 ℃ of annealing, (d) 450 ℃ of annealing, (e) 500 ℃ of annealing.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

As shown in Figure 1 and Figure 2, a kind of raising Cu ₃The method of N film heat stability specifically comprises the steps:

Step 1. will be used liquid detergent, acetone, raw spirit and deionized water ultrasonic cleaning 15 minutes successively for Si (100) substrate of deposited samples, and will be stand-by.

Step 2. will be with dopant material to place on the Cu target, then substrate will be placed on the specimen holder, and specimen holder and target surface is parallel and at a distance of 55 mm.

Step 3. background air pressure in vacuum chamber is lower than 6 * 10 ^-6During mbar, feeding flow velocity in the vacuum chamber is the pure nitrogen gas (99.99%) of 7 sccm, and cosputtering target and dopant material are by changing the area coverage of dopant material on target, covering the position, at the Cu of the synthetic different components ratio of substrate ₃NM _xFilm.

The material of described cosputtering is In, Ti.

The present invention realizes Cu by cosputtering dopant material and target ₃The raising of N film heat stability, cosputtering carries out under low temperature, subatmospheric and lower powered condition, and the material of cosputtering can be In, Ti etc.

Cu ₃M _xThe Research on Thermal Stability of N film is by at N ₂Gas protection differing temps was down annealed 20 minutes, and its relevant physical properties of Measurement and analysis is carried out then.If have the metallic copper peak to occur in the XRD of the annealing specimen spectrum, sample just is considered to begin decompose, and decomposition temperature is corresponding annealing temperature this moment.Can find out clearly that from Fig. 1 In content is 8.2at.%, and Cu ₃The decomposition temperature of the mutually prevailing sample of N is 360 ℃.

Embodiment 1

The cuprous nitride film that utilizes radio frequency magnetron sputtering method to mix at Si (100) substrate preparation different I n.At first will use liquid detergent, acetone, raw spirit and deionized water ultrasonic cleaning successively 15 minutes for the substrate of deposited samples, then substrate will be placed on parallel with the target surface and on the specimen holder of 55 mm.Background air pressure is lower than 6 * 10 in vacuum chamber ^-6During mbar, feeding flow velocity in the chamber is the pure nitrogen gas (99.99%) of 7 sccm, the pure Cu target of cosputtering (99.99%) and high-purity In (99.999%) particle on it are by changing area coverage, the covering position of In on target, at the Cu of the synthetic different components ratio of substrate _xIn _yThe N film.Operating air pressure control is 7 * 10 ^-3Mbar, pre-sputter and film deposition process were kept respectively 30 minutes.Substrate temperature control is at～333K in the deposition process, and radio-frequency (RF) input power is 60 W.

Cu _xIn _yThe Research on Thermal Stability of N film is by at N ₂Gas protection differing temps was down annealed 20 minutes, and its relevant physical properties of Measurement and analysis is carried out then.If have the metallic copper peak to occur in the XRD of the annealing specimen spectrum, sample just is considered to begin decompose, and decomposition temperature is corresponding annealing temperature this moment.Can find out clearly that from Fig. 1 In content is 8.2at.%, and Cu ₃The decomposition temperature of the mutually prevailing sample of N is 360 ℃, compared to pure Cu ₃The decomposition temperature that the N film is 300 ℃, thermostability slightly improves.

Embodiment 2

The cuprous nitride film that utilizes radio frequency magnetron sputtering method to mix in Si (100) substrate preparation different Ti.The same case study on implementation of condition (one).

Having selected Ti content is the doped with Cu of 2.2at.% ₃The N film carries out Research on Thermal Stability.Under protection of nitrogen gas, to sample annealing 20 minutes, Fig. 2 provided the XRD spectra after the annealing of sample differing temps, and as can be seen from the figure Cu(111 has just appearred in film after 400 ℃ of annealing) diffraction peak, but after 500 ℃ of annealing, the Cu in the film ₃(100) diffraction peak of N is still occupied an leading position.The thermostability of the cuprous nitride film that above presentation of results Ti mixes has improved, and the decomposition rate of film is slack-off, Cu ₃The decomposition temperature of N film, and be increased to～500.

Claims (1)

1. one kind is improved Cu ₃The method of N film heat stability is characterized in that comprising the steps:

Step 1. will be used each ultrasonic cleaning of liquid detergent, acetone, raw spirit and deionized water 15 minutes successively for Si (100) substrate of deposited samples, and will be stand-by;

Step 2. will be with dopant material to place on the Cu target, then substrate will be placed on the specimen holder, and specimen holder and target surface is parallel and at a distance of 50-60 mm;

Step 3. detects whether ground connection of target, if ground connection then reapposes, guarantees that target is earth-free;

Step 4. is carried out the HF acid corrosion of 1% concentration with Si (100) substrate, and the treatment time is 1-2min, after the HF acid treatment with plasma water flushing, dry up then place specimen holder,

Step 5. is closed vacuum chamber, vacuumizes;

Step 6. background air pressure in vacuum chamber is lower than 6 * 10 ^-6During mbar, feed pure nitrogen gas (99.99%) in vacuum chamber, cosputtering target and dopant material under the lower powered condition of low temperature are by changing area coverage, the covering position of dopant material on target, at the Cu of the synthetic different components ratio of substrate ₃NM _xFilm;

The material of described cosputtering is In, Ti;

The Cu that step 7. is prepared ₃NM _xFilm need carry out the electrology characteristic test of thermal decomposition product, guarantees that thermal decomposition product is good conductor.

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