CN100399600C - Rapid circulating crystallizing device and method for preparing nanometer crystal material - Google Patents

Abstract

The present invention discloses a rapid circulating and crystallizing (RRTA) device and method for preparing nanometer crystal material. With the rapid circulating and crystallizing (RRTA) device for preparing the nanometer crystal material, the holding temperature T<a> of a film sample 17 is firstly determined, and then a series of rapid circulating and crystallizing results of the nanometer crystal material are prepared. The relationship between the circulating index, the heating rate and the crystalline size can be obtained by comparing and analyzing the rapid circulating and crystallizing results to determine the optimum circulating index and the optimum heating rate. Finally, the rapid circulated and crystallized nanometer crystal material can be prepared according to the optimum circulating index and the optimum heating rate. The nanometer crystal material with good performance can be prepared by using the method and the device provided by the present invention.

Description

A kind of Rapid Cycle crystallization system and method for preparing nanocrystalline material

Technical field

The invention belongs to the electronic material preparing technical field, it is particularly related to the technology of preparing of crystallization electronic information thin-film material.

Background technology

Adopted muffle furnace or vacuum furnace crystallization thin film material in 90 years as last abroad, when muffle furnace or vacuum furnace crystallization thin film material, heating rate is between 0.01 ℃/s～0.5 ℃/s, general temperature retention time is more than 0.5 hour, and the crystal grain that is difficult to make nanometer scale (is seen IEEE, Trans, MAG, Vol.26, NOS, Sep.1990 P1927-1930).The American I BM Suzuki of company in 1991 proposes short annealing (RTA) method and comes crystal grain thinning (to see IEEE.Trans.MAG.Vol.26, No5, Sep.1990P1927-1930), make heating rate bring up to 10 ℃/s～50 ℃/s, insulation is at 3～15 minutes, but can not effectively suppress grain growth, simultaneously can not add magnetic field, be that magnetic thin film produces single shaft xenocryst effect, magneto-optic nanocrystal crystallization at that time is to about the 80nm, and is but extremely inhomogeneous.

In order to improve the crystal boundary noise of carbuncle type magneto optical disk, improve the optical surface uniformity, the inventor proposes nano-crystallization Bi:Al:DyIG magneto-optic memory technique method repeatedly in April, 1993, adopting an iodine-tungsten lamp is thermal source, and heating rate is brought up to 10 ℃/s～70 ℃/s, at interval crystallization thin film, at that time with the crystal grain nano-crystallization to about the 40nm, but technology is extremely unstable, and little when big during crystal grain, optical surface greatly has improvement.

Existing crystallization process adopts rapid crystallization apparatus and method (being called for short the RTA method), and as shown in Figure 1, it is that sample is placed on sample area, open heating lamp and heat rapidly, when temperature reaches crystallization temperature, stop heating, begin insulation, heat treatment finishes when being cooled to uniform temperature.

Conventional crystallization process heating rate is between 0.01～0.5 ℃/s, crystallization time and temperature control are long, generally be incubated, can not suppress grain growth, can not add magnetic field more than 0.5 hour, crystallite dimension is more than 0.4 μ m, RTA method heating rate generally is incubated at 3～15 minutes between 1～50 ℃/s, can not suppress grain growth, can not add magnetic field, crystallite dimension is more than 80nm.

Advantage of the present invention: heating rate soon (1 ℃～100 ℃/s) between, crystallization time and temperature control time are short, and (below 0.5 hour) is lacked in general insulation, can suppress grain growth, can add magnetic field magnetic material is carried out texture, crystallite dimension is below 0.05 μ m.

Summary of the invention

The purpose of this invention is to provide a kind of Rapid Cycle crystallization (being called for short RRTA) apparatus and method that prepare nanocrystalline material, adopt method and apparatus provided by the invention can prepare the nanocrystal of function admirable.

A kind of Rapid Cycle crystallization (RRTA) device for preparing nanocrystalline material of the present invention, it comprises: quartz ampoule termination sealing plug 5, steam vent 6, cooling water pipe 7, temperature test and controller 8, iodine-tungsten lamp 9, power supply 15, sample 17, metal shell 18; It is characterized in that it also comprises: the Helmholtz coil 16 in quartz ampoule 10, nitrogen system valve 11, vacuum system valve 12, nitrogen cylinder 13, vacuum-pumping system 14, magnetic field, Helmholtz's line 16 is distinguished snares at quartz ampoule 10 two ends, cooling water pipe 7 is positioned at metal shell 18 inboards, iodine-tungsten lamp 9 is positioned at quartz ampoule 10 outer central areas, and is evenly distributed around metal shell 18 inboard middle sections; Quartz ampoule 10 is placed in the center of cylinder metal shell 18; Temperature test and controller 8 are placed in the outer survey of the regional quartz ampoule 10 of placing sample 17; Nitrogen cylinder 13 and vacuum-pumping system 14 are connected by three-way connector, link to each other with quartz ampoule 10 mouths with rubber tube, as shown in Figure 1 again.

Need to prove.

During a kind of Rapid Cycle crystallization (RRTA) for preparing nano crystal material provided by the invention is installed, there are quartz ampoule brachycephaly sealing plug 1, steam vent 2, quartz ampoule 6 to constitute RRTA vacuum environment chambers; For the vacuum environment chamber provides nitrogen, be used for atmosphere protection by nitrogen system valve 7, nitrogen cylinder 9; Realize environment temperature reduction by cooling water pipe 3.

Compare with crystallization (RRTA) device of traditional preparation nano crystal material, device of the present invention has following characteristics:

1) increased magnetic field device, in annealing process,, therefore can improve the performance of preparing nano crystal material owing to applied magnetic field;

2) the vacuum chamber volume is little, and is in light weight, and thermal capacity is little, adopts and directly heats with iodine-tungsten lamp, can realize being rapidly heated;

3) because the nitrogen protection sole duty is provided, so crystallization process is to carry out under vacuum environment, prepares the nanocrystalline metal membrane material and is difficult for oxidation.

A kind of method for preparing the Rapid Cycle crystallization (RRTA) of nanocrystalline material provided by the invention, it is to adopt following step:

Step 1, determine the holding temperature T of film sample 17 _a, concrete grammar is

At first, carry out crystallization temperature experiment for film sample 17, can adopt differential scanning calorimetry for crystallization temperature interpretation determine crystallization temperature T ₀Value, the method (promptly making the variations in temperature of diffraction maximum) that also can adopt the x x ray diffraction for crystallization temperature interpretation determine initial crystallization temperature T ₀Value;

Then, utilize formula: T _a=T ₀+ 20 ℃, just can determine holding temperature T _aValue;

Step 2, the individual film sample 17 that needs crystallization of N (N is a natural number) put into the centre of RRTA device quartz ampoule 10;

Step 3, seal, start pumped vacuum systems 14 and bleed with the port of the Rapid Cycle crystallization system (being called for short the RRTA device) of 5 pairs of preparations of quartz ampoule sealing blocking nanocrystalline material;

Step 4, open iodine-tungsten lamp 9 heater switch to film sample 17 heat rapidly (the heating rate scope 1 ℃～100 ℃/s);

Step 5, rise to holding temperature T _aIn time, stop to heat, and natural cooling or water-cooled are to temperature T _b(150 ℃);

Step 6, repeating step 2,3,4 is to step 5 repeatedly, just can prepare the rapid crystallization result of a series of nano crystal materials corresponding to different heating rates, different temperature retention time and different cycle-indexes;

Step 7, at first, the rapid crystallization result who obtains for step 6 surveys its microcosmic grain size, shown in Fig. 1-1, Fig. 1-2, Fig. 1-3;

Then, the rapid crystallization result who obtains for step 6 surveys its macro property: electricity, magnetics, optical property;

At last, compare analysis, just can determine: the electromagnetism optical property relation of cycle-index and heating rate and grain size and crystal grain for the result who tests above;

Select best crystallization result in step 8, the conclusion that from step 7, obtains: cycle-index, heating rate and holding temperature;

Step 9, utilize the cycle-index, heating rate and the holding temperature that obtain in the step 8, the method that adopts step 2-5 to provide just can be prepared nano crystal material.

Need to prove that the characteristics of the method for the Rapid Cycle crystallization of preparation nanocrystalline material recited above are Rapid Cycle heat treatment, we are referred to as the method (english abbreviation: RRTA is called for short the RRTA method) of nanocrystalline material circulation crystallization.

The essence of the method for a kind of Rapid Cycle crystallization (RRTA) for preparing nanocrystalline material of the present invention is: utilize preparation nanocrystalline material Rapid Cycle crystallization provided by the invention (RRTA) device, at first determine the holding temperature T of film sample 17 _a, then, preparing the Rapid Cycle crystallization result of a series of nanocrystalline materials, by it is compared analysis, just can obtain: the relation of cycle-index and heating rate and grain size, determine optimum cycle number of times and optimum temperature rise speed; At last, just can prepare the nanocrystalline material of process Rapid Cycle crystallization according to optimum cycle number of times and optimum temperature rise speed.

Operation principle of the present invention:

The present invention is a kind of peculiar methods for preparing nanocrystalline new material and nanocrystal refinement, be adapted to the nanocrystalline formation and the nanocrystal refinement of magnetic, light, conductive film and various metal, sull especially, it is based on the three big mechanism that we propose: a) nucleus forms and the grain growth competition theory: promptly when film Rapid Cycle crystallization, nucleus forms and grain growth is a competition process, and the condition that nucleus forms the speed maximum is not the condition of grain growth maximum.Suppress grain growth and can quicken nucleus formation, make crystal grain be in nanoscale, will make T a little more than initial crystallization temperature by the temperature parameter T of crystallization simultaneously; B) the autocatalysis temperature mechanism of nano-crystallization: Rapid Cycle annealing is after the period 1 temperature retention time finishes, form nucleus and crystalline phase and amorphous phase interface, cooling rapidly makes the crystal boundary place form defective, this defective provides boundary condition for generating nucleus between intensification and soak second round, the acceleration nucleus generates, so be referred to as " crystallization catalysis automatically "; C) nanocrystalline grain size is relevant with heating rate in the RRTA method, ferroelectric thin film, ferromagnetic thin film, ferrite film and piezoelectric membrane etc. increase crystallite dimension with heating rate and reduce, performance also changes thereupon, in temperature-rise period, also have simultaneously crystalline phase to generate, more than the theoretical formula of three parts as follows:

$U=U_0\left(\frac{T-T_0}{T_0}\right)\exp (-\frac{\mathrm{\&Delta;E}}{k_{B}T})+......$ Nucleus generating rate formula

$\mathrm{\&gamma;}=\frac{{\mathrm{\&gamma;}}_0}{\mathrm{\&alpha;}}\mathrm{Texp}(-\mathrm{\&Delta;E}/k_{B}T)+......$ The grain growth rate equation

$\mathrm{\&chi;}=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{1}{[1+\exp (-k_{T}t)/(i-1)\mathrm{\&Delta;C}]}$ Crystal transition fraction formula

T ₁Nucleus growth maximum rate formula, T ₂Grain growth maximum rate temperature, T _aDetermine by initial crystallization temperature, can determine, promptly do the variations in temperature of diffraction maximum, at no peak with the peak dot place just occurred and determine T by differential scanning calorimetry or x x ray diffraction ₀, T then _a=T ₀+ 20 ℃, to metallic film T ₀=320～480 ℃, T _a=500～520 ℃, to ferroelectric thin film, ferromagnetic thin film, ferrite film and piezoelectric membrane and magneto-optic thin film T ₀=430～550 ℃, T _a=620～650 ℃

Advantage of the present invention: compare with existing RTA method, the present invention has short, the short characteristics such as (below 0.5 hours) of temperature retention time of crystallization process heating rate fast (between 1 ℃～100 ℃/s), crystallization time and temperature control time, and the nanocrystalline material of preparing has good electricity, magnetic, optical property.But fields such as the present invention's extensive use ferroelectric thin film, ferromagnetic thin film, ferrite film and piezoelectric membrane nano-crystallization.

Description of drawings

Fig. 1 is Rapid Cycle nano-crystallization (RTA) schematic diagram

Wherein 1 is temp probe, the 2nd, and sample mounting table, the 3rd, iodine-tungsten lamp, the 4th, very hot power supply.

Fig. 2 is Rapid Cycle nano-crystallization (RRTA) installation drawing

Wherein, the 5th, quartz ampoule termination sealing plug, the 6th, be steam vent, the 7th, be cooling water pipe, be used for the environment temperature reduction stage, the 8th, temperature test and controller, the 9th, iodine-tungsten lamp, the 10th, quartz ampoule, the 11st, nitrogen system valve, the 12nd, vacuum system valve, the 13rd, nitrogen cylinder, the 14th, vacuum-pumping system, the 15th, power supply, the 16th, the Helmholtz coil in magnetic field, the 17th, sample, 18 shells, 19 quartzy ozzles, 20 rubber tubes.

Fig. 3 is Rapid Cycle nano-crystallization (RRTA) temperature profile

Wherein, the 21st, general crystallization process, the 22nd, temperature-rise period, the 23rd, temperature-fall period.

Fig. 4 selects holding temperature to be respectively: 485 ℃, 500 ℃, 520 ℃, 550 ℃ are carried out the crystallization processing, the crystallization result are carried out X-ray analysis, the X-ray analysis result

Fig. 5 is that heat temperature raising speed is respectively 10 ℃/s, 30 ℃/s, 60 ℃/s, circulates temperature retention time 1 minute, T 6 times _aThe atomic force microscope figure of=525 ℃ of experimental results

Wherein, Fig. 5-1 is that 10 ℃/s of heating rate, Fig. 5-2 are 60 ℃/s of heating rate for 30 ℃/s of heating rate, Fig. 5-3.

Fig. 6 is that cycle-index is respectively 1,3,6 time, 60 ℃/s of heating rate, temperature retention time 1 minute, T _aThe atomic force microscope figure of=525 ℃ of experimental results

Wherein, Fig. 6-1 cycle-index is that 1 time, Fig. 6-2 cycle-index are that 3 times, Fig. 6-3 cycle-index are 6 times.

Fig. 7 is that temperature retention time is respectively 1min, 2mins, 3mins, 4mins, 60 ℃/s of heating rate, T _aThe atomic force microscope figure of=525 ℃ of experimental results, wherein Fig. 7-1 temperature retention time is that 1min, Fig. 7-2 temperature retention times are that 2mins, Fig. 7-3 temperature retention times are that 3mins, Fig. 7-4 temperature retention times are 4mins

Fig. 8 is a Rapid Cycle crystallization schematic diagram of the present invention

Therefrom as can be seen: nucleus growth maximum rate temperature T ₁Than grain growth maximum rate temperature T ₂Low.

Embodiment

Adopt apparatus and method provided by the invention to prepare CoNbZr (cobalt niobium zirconium) nanocrystalline material

1. determine the holding temperature T of CoNbZr film ₀:

The CoNbZr film is put into the quartz ampoule central area,

Be evacuated down to 1 * 10 ^-1Pa;

Heat temperature raising speed is 10 ℃/s;

Select holding temperature to be respectively: 485 ℃, 500 ℃, 520 ℃, 550 ℃ are carried out crystallization and handle, and the crystallization result is carried out X-ray analysis, the X-ray analysis result as shown in Figure 4,

As can be seen from Figure 4,500 ℃ is the initial crystallization temperature T of CoNbZr film _aValue:

T _a＝T ₀+20℃，T _a＝500℃+20℃＝520℃。

2, determine (on average) speed that heats up:

The CoNbZr film is put into quartzy central area,

Be evacuated down to 1*10 ^-1Pa,

Heat temperature raising speed is respectively 10 ℃/s, and 30 ℃/s, 60 ℃/s,

Circulate temperature retention time 1 minute, T 6 times _a=520 ℃,

Obtain: heat temperature raising speed is respectively 10 ℃/s, and 30 ℃/s, 60 ℃/s and circulation 6 times and the crystallization result of temperature retention time in the time of 1 minute; Learn after tested, when heating temperature rise rate crystallization the best as a result when being 60 ℃/s.

3, determine relation between the cycle-index

The CoNbZr film is put into quartzy central area

Be evacuated down to 1 * 10 ^-1Pa

60 ℃/s of heating rate

Cycle-index is respectively 1,3,6 time, T _a=525 ℃.

Fig. 6-1 cycle-index is respectively 1 time

Fig. 6-2 cycle-index is respectively 3 times

Fig. 6-3 cycle-index is respectively 6 times.

Obtain: cycle-index is respectively 1,3,6 time, and 60 ℃/s of heating rate, temperature retention time 1 minute and holding temperature T _aCrystallization result in the time of=525 ℃; Learn after tested, when heating temperature rise rate crystallization the best as a result when being 6 times.

4, determine temperature retention time:

Be evacuated down to 1 * 10 ^-1Pa,

30 ℃/s of heating rate,

Circulate T 6 times _a=525 ℃.

Temperature retention time is 1min, 2mins, 3mins, 4mins and 6 crystallization results with 30 ℃/s of timely heating rate of circulation; Learn crystallization the best as a result when the heat tracing time is 1min after tested.

Fig. 7-1 temperature retention time is 1min

Fig. 7-2 temperature retention time is 2mins

Fig. 7-3 temperature retention time is 3mins

Fig. 7-4 temperature retention time is 4mins

Influence interpretation of result by above cycle-index, heating rate and temperature retention time for grain size and electromagnetism optical property thereof, determine that the optimum cycle number of times is that 6 times, best temperature rise rate are 525 ℃ of 60 ℃/s, temperature retention time 1min, holding temperatures, according to the cycle-index that obtains, temperature rise rate and holding temperature, adopt method provided by the invention just can prepare the brilliant material of CoNbZr film nano.The brilliant material of this CoNbZr film nano has brilliant size below 50nm, and the electromagnetism optical property significantly improves.

Adopt RRTA method provided by the invention that various Fe bases, Co base, GMR and MTJ material are carried out nano-crystallization, the nanocrystalline yardstick that made the material round Realization, and can control effectively to nanocrystal from temperature, heating rate, temperature retention time and periodicity; This method can be widely used in fields such as ferroelectric thin film, ferromagnetic thin film, ferrite film and piezoelectric membrane nano-crystallization simultaneously.

Claims (2)

1. Rapid Cycle crystallization system for preparing nanocrystalline material, it comprises: quartz ampoule termination sealing plug (5), steam vent (6), cooling water pipe (7), temperature test and controller (8), iodine-tungsten lamp (9), power supply (15), sample (17), metal shell (18); It is characterized in that it also comprises: the Helmholtz coil (16) in quartz ampoule (10), nitrogen system valve (11), vacuum system valve (12), nitrogen cylinder (13), vacuum-pumping system (14), magnetic field; Snare is at quartz ampoule (10) two ends respectively with Helmholtz's line (16), and cooling water pipe (7) is positioned at metal shell (18) inboard, and iodine-tungsten lamp (9) is positioned at the outer central area of quartz ampoule (10), and is evenly distributed around the inboard middle section of metal shell (18); Quartz ampoule (10) is placed in the center of cylinder metal shell (18); Temperature test and controller (8) are placed in the outer survey of the regional quartz ampoule (10) of placing sample (17); Nitrogen cylinder (13) is connected by three-way connector with vacuum-pumping system (14), uses rubber tube to link to each other with quartz ampoule (10) mouth again.

2. a kind of Rapid Cycle crystallization system for preparing nanocrystalline material according to claim 1 is characterized in that utilizing this device to prepare the method for the Rapid Cycle crystallization of nanocrystalline material, is to adopt following step:

Step 1, determine the holding temperature T of film sample (17) _a, concrete grammar is:

At first, carry out crystallization temperature experiment for film sample (17), can adopt differential scanning calorimetry to crystallization temperature interpretation determine crystallization temperature T ₀Be worth, also can adopt the method for x x ray diffraction, make the variations in temperature of diffraction maximum, initial crystallization temperature T is determined in interpretation to crystallization temperature ₀Value;

Then, utilize formula: T _a=T ₀+ 20 ℃, just can determine holding temperature T _aValue;

Step 2, the individual film sample (17) that needs crystallization of N (N is a natural number) put into the centre of Rapid Cycle crystallization system (being called for short the RRTA device) quartz ampoule (10);

Step 3, seal blocking (5) with quartz ampoule the port of RRTA device of preparation nanocrystalline material is sealed, start pumped vacuum systems (14) and bleed;

Step 4, open iodine-tungsten lamp (9) heater switch to film sample (17) heat rapidly (the heating rate scope 1～100 ℃/s);

Step 5, rise to holding temperature T _aIn time, stop to heat, and natural cooling or water-cooled are to temperature T _b(150 ℃);

Step 6, repeating step 2,3,4 is to step 5 repeatedly, just can prepare the rapid crystallization result of a series of nano crystal materials corresponding to different heating rates, different temperature retention time and different cycle-indexes;

Step 7, at first, the rapid crystallization result who obtains for step 6 surveys its microcosmic grain size;

Then, the rapid crystallization result who obtains for step 6 surveys its macro property: electricity, magnetics, optical property;

At last, compare analysis, just can determine: the electromagnetism optical property relation of cycle-index and heating rate and grain size and crystal grain for the result who tests above;

Select best crystallization result in step 8, the conclusion that from step 7, obtains: cycle-index, heating rate and holding temperature;

Step 9, utilize the cycle-index, heating rate and the holding temperature that obtain in the step 8, the method that adopts step 2-5 to provide just can be prepared nano crystal material.

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