CN102832339A - Al-Ge-Te phase-change material for phase change memory - Google Patents

Abstract

The invention relates to an Al-Ge-Te phase-change material for a phase change memory, which has a chemical formula of Al(100-x-y)GexTey, wherein x plus y is less than 100 but is more than 50, and x divided by y is less than 4 but is more than 0.25. The Al-Ge-Te phase-change material is used as a storage medium in the phase change memory, and the conversion of high and low resistances can be realized under the action of electric signals. Electric signals act on the phase change memory based on the Al-Ge-Te phase-change material, so the low resistance value is larger than the low resistance value of a device based on the conventional Ge-Te phase-change material, so the low power consumption requirement is satisfied. Moreover, the Al-Ge-Te phase-change memory maintains the normal high and low resistance difference after being circularly erased for 103 times, so the circulation service life of the device is long.

Description

The Al-Ge-Te phase-change material that is used for phase transition storage

Technical field

The present invention relates to be used for the Al-Ge-Te phase-change material of phase transition storage, belong to semi-conducting material and make the field.

Background technology

Memory is the important component part of present semi-conductor market, is the foundation stone of information technology, no matter in life, still in national economy, plays an important role.At present, the storage products of memory mainly contains: flash memory, disk, dynamic memory, static memory etc.Other non-volatile technology: ferroelectric RAM, magnetic ram, CNT RAM, resistance-type RAM, copper RAM (Copper Bridge), Hologram Storage, single electron storage, molecule storage, polymer storage, racing track storage (RacetrackMemory), detection storage (Probe Memory) etc. have also received extensive studies as the candidate of memory of future generation.These technological each have their own characteristics, but mostly also be in theoretical research or orientation test stage, distance practicality on a large scale is also very remote.And phase transition storage has been walked out the laboratory at present, has moved towards market, for example, and the multicore sheet encapsulation 512Mbit phase change memory grain products of the Omneo of Numonyx company series phase change memory chip product and Samsung.At present, the NOR type flash memory in the replacement consumer electronics field has become the development trend of phase transition storage.

The basic principle of phase transition storage is to utilize the reversible transition of storage medium between high resistance and low resistance wherein to realize the storage of " 1 " and " 0 ".Realize that through utilizing the signal of telecommunication to control the high low-resistance continuous variation of storage medium can realize multistage storage, thereby significantly improve the information storage capability of memory.In phase transition storage, realize through the reversible transition of phase-change material between amorphous and polycrystalline during the height changes in resistance.

Up to the present the Ge-Te series material is furtherd investigate as phase-change storage material.As when the crystallization with the phase-change material of growth-dominated, the GeSbTe phase-change material that GeTe takes as the leading factor with nucleation during with crystallization is compared has higher crystallization rate, for the high speed operation based on the phase transition storage of this material provides guarantee.The GeTe material has than the better amorphous state thermal stability of traditional GeSbTe material, lays a good foundation for the basic phase transition storage of GeTe has better data holding ability.But the resistivity during owing to the GeTe crystallization is lower than the GeSbTe material, and the phase transition storage of GeTe base is compared with the phase transition storage of GeSbTe base needs higher electric current when carrying out write operation.Overcoming GeTe base phase transition storage needs the shortcoming of very high write-operation current, guarantees the high speed operation ability of memory and the direction that good data holding ability becomes present phase-change material research simultaneously.

Summary of the invention

The objective of the invention is to overcome the deficiency of above prior art, a kind of Al-Ge-Te phase-change material is provided.This phase-change material does not need higher electric current when carrying out write operation, and can guarantee the high speed operation ability of memory and good data holding ability simultaneously.

For realizing above-mentioned purpose, the present invention adopts following technical scheme: be used for the Al-Ge-Te phase-change material of phase transition storage, be the compound of aluminium, germanium and tellurium element composition.

Preferably, chemical general formula is Al _100-x-yGe _xTe _y, 50＜x+y＜100,0.25＜x/y＜4 wherein, promptly Al shared atomicity percentage in Al-Ge-Te is lower than 50% and is higher than 0, the ratio Ge/Te of Ge and Te shared atomicity in Al-Ge-Te greater than 0.25 less than 4.

Preferably, 80＜x+y＜100,0.8＜x/y＜1.25.

Preferably, ${\mathrm{Al}}_{\frac{300}{23}}{\mathrm{<figure-callout\; id="1000"\; label="Ge"\; filenames="HDA00002122661500021.png"\; state="\{\{state\}\}">Ge</figure-callout>}}_{\frac{1000}{23}}{\mathrm{Te}}_{\frac{1000}{23}}.$

Preferably, the said preparation method who is used for the Al-Ge-Te phase-change material of phase transition storage comprises physical vaporous deposition, chemical vapour deposition technique, galvanoplastic, sol-gal process, deposition of metal organic method.

Wherein, Physical vaporous deposition (Physical Vapor Deposition; PVD) be under vacuum condition, adopt physical method, with material source---solid or liquid surface are gasificated into gaseous atom, molecule or partial ionization and become ion; And, has the technology of the film of certain specific function in the matrix surface deposition through low-pressure gas (or plasma) process.

Preferably, the main method that physical vaporous deposition of the present invention forms aluminium-germanium-tellurium phase change film material comprises sputter coating, vacuum evaporation, arc-plasma plating, ion film plating, and molecular beam epitaxy etc.

Preferably, said sputter coating method target method be selected from following any one:

(1) selects Al-Ge-Te three element alloy target magnetic control co-sputtering for use;

(2) select Al, Ge, Te simple substance target magnetic control co-sputtering for use;

(3) select the simple substance target of a kind of element among Al, Ge and the Te and the alloys target magnetic control co-sputtering of other two kinds of elements for use.

Described sputter coating method may further comprise the steps:

(1) will clean after the oven dry the substrate vacuum sputtering of packing into indoor, feed gas Ar build-up of luminance when vacuum degree reaches certain value;

(2) rotate the sample stage of loading substrate, open shielding power supply, Ar Flow-rate adjustment to sputter state;

(3) powered-down after deposition is accomplished stops to feed Ar, stops operating, and takes out substrate, carries out following process.

Preferably, the build-up of luminance flow of the said Ar of step (1) is 200sccm.

Preferably, the sputter flow of the said Ar of step (2) is 50sccm.

Preferably, vacuum degree is≤1 * 10 ^-4Pa, sputtering pressure are 0.1-0.5Pa, and sputter gas is Ar, and sputter temperature is 20-300 ℃, and sputtering time is 0.5-30 minute, and deposit film thickness is the 5-300 nanometer.

Preferably, vacuum degree is 1 * 10 ^-4Pa, sputtering pressure are 0.8Pa, and sputter gas is Ar, and sputter temperature is 30 ℃, and deposit film thickness is 50 nanometers;

Preferably, during simple substance target magnetic control co-sputtering, the radio-frequency power supply power of each target is: Al 10-30W, Ge 10-30W, Te5-30W.

Preferably, during simple substance target magnetic control co-sputtering, the radio-frequency power supply power of each target is: Al 30W, Ge 25W, Te 10W.

Chemical vapour deposition (CVD) (Chemical Vapor Deposition is called for short CVD) is that reactive material issues biochemical reaction in the gaseous state condition, generates the solid matrix surface that solid matter is deposited on heating, and then makes the technology of solid material.It belongs to the gaseous state mass transport process of former subcategory in essence.When preparing aluminium-germanium-tellurium phase change film material, on the solid matrix surface, the method for the raw material through chemical reaction that contains Al, Ge and Te is respectively generated solid-state aluminium-germanium-tellurium phase change film material with the method.

Described chemical vapour deposition technique may further comprise the steps:

(1) substrate that will clean after the oven dry places clean quartz ampoule middle part; Quartz ampoule is put into electric furnace; Make the quartz ampoule middle part be positioned at the central area of electric furnace; The mist of the argon gas of the hydrogen of feeding 100sccm and 100sccm is as carrier gas in quartz ampoule then, and ventilating begins heating after 60 minutes;

When (2) electric furnace central area temperature reached depositing temperature, feeding contained the Ge element, Te element, the raw material of Al element in said carrier gas;

(3) stop feeding after deposition is accomplished and contain the Ge element, the Te element, the raw material of Al element is closed electric furnace simultaneously, continues the hydrogen of feeding 100sccm and argon gas mist to the temperature of 100sccm and reduces to room temperature;

(4) stop hydrogen and argon gas and feed, take out sample, carry out following process;

Preferably, the raw material that contains the Ge element is selected from [N (CH ₃) ₂] ₄Ge and GeH ₄

Preferably, the raw material that contains the Ge element is selected from [N (CH ₃) ₂] ₄Ge;

Preferably, the raw material that contains the Te element is selected from (C ₃H ₇) ₃Te;

Preferably, the raw material that contains Al is selected from Al (CH ₃) ₃

Preferably, the scope of depositing temperature is 300 ℃-550 ℃;

Preferably, depositing temperature is 350 ℃;

The present invention preparation during described phase-change material through selecting proper A l for use, Ge, Te atomicity ratio has made Al _100-x-yGe _xTe _yPhase-change material can be realized the conversion repeatedly of high low resistance as storage medium under signal of telecommunication operation, and in that not have to keep resistance under the situation of operation signal constant.

In addition, the phase transition storage that on this phase-change material basis, prepares has the following advantages: the phase transition storage low resistance state resistance (10 of Al-Ge-Te base ⁴Ohm) be higher than low-resistance (10 based on the phase transition storage of traditional Ge-Te material ³Ohm), reduce the required electric current of write operation, be beneficial to reduce power consumption.10 ³Inferior circulation or higher cycling still have tangible height resistance difference afterwards, guarantee having extended cycle life of device.

Description of drawings

Fig. 1 based on the memory of the Al-Ge-Te material of PVD method preparation 300 nanosecond pulsewidth the pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ⁴Ohm has improved an one magnitude than GeTe base phase transition storage.V Fig. 2 utilizes electric pulse to carry out repeatable operation based on the memory of the Al-Ge-Te material of PVD method preparation, and the cycling life-span reaches 10 ³More than, proved that the Al-Ge-Te material has well phase transformation ability repeatedly.

Fig. 3 is based on the electricity operation of the phase transition storage of GeTe material.Device 1000 nanosecond pulsewidth pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ³Ohm.

Fig. 4 based on the memory of the Al-Ge-Te material of CVD method preparation 200 nanosecond pulsewidth the pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ⁴Ohm has improved an one magnitude than GeTe base phase transition storage.

Fig. 5 utilizes electric pulse to carry out repeatable operation based on the memory of the Al-Ge-Te material of CVD method preparation, and the cycling life-span reaches 10 ³More than, proved that the Al-Ge-Te material has well phase transformation ability repeatedly.

Embodiment

Below through specific instantiation technical scheme of the present invention is described.Should be understood that these embodiment only to be used to the present invention is described and be not used in the restriction scope of the present invention.

Embodiment one

Preparation ${\mathrm{Al}}_{\frac{300}{23}}{\mathrm{<figure-callout\; id="1000"\; label="Ge"\; filenames="HDA00002122661500021.png"\; state="\{\{state\}\}">Ge</figure-callout>}}_{\frac{1000}{23}}{\mathrm{Te}}_{\frac{1000}{23}}:$

Select the sputter coating method in the physical vaporous deposition (PVD) for use, adopt Al, Ge, Te simple substance target utilize the magnetic control co-sputtering prepared to form respectively on silicon substrate, may further comprise the steps:

(1) will clean after the oven dry the substrate vacuum sputtering of packing into indoor, vacuum degree is 1 * 10 ^-4Logical people's gas Ar build-up of luminance during Pa, the build-up of luminance flow is 200sccm.

(2) rotate the sample stage of loading substrate, open shielding power supply, with Ar Flow-rate adjustment to sputter state, flow is 50sccm.

(3) powered-down after deposition is accomplished stops to feed Ar, stops operating, and takes out substrate, carries out following process.

Wherein, sputtering pressure is 0.18Pa, and sputter temperature is 30 ℃, the Al target, and Ge target and Te target adopt radio-frequency power supply respectively, the DC power box DC power supply.The radio-frequency power supply power that is applied on the Al target is 30W, and the DC power supply power that is applied to the Ge target is 25W, and the DC power supply power that is applied to the Te target is 10W, and sputtering time is 5 minutes, and deposit film thickness is 50 nanometers;

In addition, except using the simple substance target co-sputtering, can also prepare through following two kinds of methods: (1) is selected Al-Ge-Te three element alloy target magnetic control co-sputtering for use; (2) select the simple substance target of a kind of element among Al, Ge and the Te and the alloys target magnetic control co-sputtering of other two kinds of elements for use, the parameter condition of concrete technology takes the circumstances into consideration to set.

What need special instruction is that in actual applications, final component of phase-change storage material and thickness can decide by different targets change power and different sputtering times.In addition, the physical deposition preparation method of phase-change storage material is not limited in cosputtering technology, also can use other method for manufacturing thin film; For example; In other embodiments, use vacuum evaporation, arc-plasma plating, ion film plating, and molecular beam epitaxy etc.

Al-Ge-Te series phase-change storage material through being prepared from above-mentioned carries out each item test, is used for weighing the phase-change characteristic of phase-change storage material, and shown in Fig. 1-2, Fig. 3 be the test effect of general phase transition storage based on the GeTe storage medium; It is thus clear that, GeTe base phase change memory device 1000 nanosecond pulsewidth the pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ³Ohm; Based on the memory of the Al-Ge-Te material of PVD method preparation 300 nanosecond pulsewidth the pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ⁴Ohm has improved an one magnitude than GeTe base phase transition storage.

Embodiment two

Preparation ${\mathrm{Al}}_{\frac{300}{23}}{\mathrm{<figure-callout\; id="1000"\; label="Ge"\; filenames="HDA00002122661500021.png"\; state="\{\{state\}\}">Ge</figure-callout>}}_{\frac{1000}{23}}{\mathrm{Te}}_{\frac{1000}{23}}:$

Chemical vapour deposition technique prepares aluminium-germanium-tellurium phase change film material, may further comprise the steps:

(1) substrate that will clean after the oven dry places clean quartz ampoule middle part; Quartz ampoule is put into electric furnace; Make the quartz ampoule middle part be positioned at the central area of electric furnace; And then the mist of argon gas of hydrogen and 100sccm that feeds 100sccm in the quartz ampoule is as carrier gas, and ventilating begins after 60 minutes to heat;

When (2) electric furnace central area temperature reaches depositing temperature, in said carrier gas, feed the raw material of Ge, Te and Al element: [N (CH ₃) ₂] ₄Ge, (C ₃H ₇) ₃Te, Al (CH ₃) ₃

(3) deposition stops to feed the raw material that contains Ge, Te and Al element after accomplishing, and closes electric furnace simultaneously, continues the hydrogen of feeding 100sccm and argon gas mist to the temperature of 100sccm and reduces to room temperature;

(4) stop hydrogen and argon gas and feed, take out sample, carry out following process.

Said CVD preparation technology parameter is: carrier gas is the mist of argon gas of hydrogen and the 100sccm of 100sccm; [N (CH during depositing Al-Ge-Te film ₃) ₂] ₄Ge, (C ₃H ₇) ₃Te, Al (CH ₃) ₃Flow be respectively 10sccm, 10sccm and 3sccm.Substrate temperature is 350 ℃ during deposition.

Through the above-mentioned Al-Ge-Te series phase-change storage material that is prepared from is carried out each item test, be used for weighing the phase-change characteristic of phase-change storage material, shown in Fig. 4-5; It is thus clear that, based on the memory of the Al-Ge-Te material of CVD method preparation 200 nanosecond pulsewidth the pulse voltage operation under resistance with the variation of voltage, low-resistance is 10 ⁴Ohm has improved an one magnitude than GeTe base phase transition storage; Memory based on the Al-Ge-Te material of CVD method preparation utilizes electric pulse to carry out repeatable operation, and the cycling life-span reaches 10 ³More than, proved that the Al-Ge-Te material has well phase transformation ability repeatedly.

What need indicate is; More than two embodiment only be for the preparation aluminium-germanium-tellurium phase change film material preferred embodiment non-to any formal and substantial restriction of the present invention; Except PVD and CVD, the present invention can also pass through preparation aluminium-germanium-tellurium phase change film materials such as galvanoplastic, sol-gal process and deposition of metal organic method; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the inventive method, also can make some improvement and replenish, these improvement and replenish and also should be regarded as protection scope of the present invention.Allly be familiar with the professional and technical personnel, under the situation that does not break away from the spirit and scope of the present invention, the technology contents that is disclosed more than capable of using and a little change of making, modify the equivalent variations with differentiation, be equivalent embodiment of the present invention; Simultaneously, the change of any equivalent variations that all foundations essence technology of the present invention is done the foregoing description, modify and differentiation, all still belong in the scope of technical scheme of the present invention.

Claims (11)

1. Al-Ge-Te phase-change material that is used for phase transition storage, its chemical general formula is Al _100-x-yGe _xTe _y, 50＜x+y＜100,0.25＜x/y＜4 wherein.

2. a kind of Al-Ge-Te phase-change material that is used for phase transition storage as claimed in claim 1, wherein 80＜x+y＜100,0.8＜x/y＜1.25.

3. like the preparation method of claims 1 or 2 described Al-Ge-Te phase-change materials, be selected from physical vaporous deposition, chemical vapour deposition technique, galvanoplastic, sol-gal process and deposition of metal organic method.

4. preparation method as claimed in claim 3 is characterized in that, described physical vaporous deposition is selected from sputter coating method, vacuum evaporation embrane method, arc-plasma coating method, ion film plating and becomes embrane method with molecular beam epitaxy.

5. preparation method as claimed in claim 4, wherein, the sputter coating method may further comprise the steps:

(1) will clean after the oven dry the substrate vacuum sputtering of packing into indoor, feed gas Ar build-up of luminance when reaching certain vacuum and spending;

(2) rotate the sample stage of loading substrate, open shielding power supply, Ar Flow-rate adjustment to sputter state;

(3) powered-down after deposition is accomplished stops to feed Ar, stops operating, and takes out substrate, carries out following process;

Wherein, vacuum degree is≤1 * 10 ^-4Pa, sputtering pressure are 0.1-0.5Pa, and sputter gas is Ar, and sputter temperature is 20-300 ℃, and sputtering time is 0.5-30 minute, and deposit film thickness is the 5-300 nanometer.

6. preparation method as claimed in claim 5 is characterized in that, the build-up of luminance flow of the said Ar of step (1) is 200sccm.

7. preparation method as claimed in claim 5 is characterized in that, the sputter flow of the said Ar of step (2) is 50sccm.

8. like the arbitrary described preparation method of claim 4-7, it is characterized in that said sputter coating method is selected from:

(1) selects Al-Ge-Te three element alloy target magnetic control co-sputtering for use;

(2) select Al, Ge, Te simple substance target magnetic control co-sputtering for use;

(3) select the simple substance target of a kind of element among Al, Ge and the Te and the alloys target magnetic control co-sputtering of other two kinds of elements for use.

9. preparation method as claimed in claim 8 is characterized in that, the radio-frequency power supply power of each target is when selecting Al, Ge, Te simple substance target magnetic control co-sputtering for use: Al 10-30W, Ge 10-30W, Te 5-30W.

10. preparation method as claimed in claim 3 is characterized in that the raw material of said chemical vapour deposition technique is selected from [N (CH ₃) ₂] ₄Ge, GeH ₄, (C ₃H ₇) ₃Te and Al (CH ₃) ₃

11. the application of Al-Ge-Te phase-change material in phase transition storage according to claim 1 or claim 2.

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