CN101752497B - Phase-change storage unit with low power consumption and high stability and preparation method thereof - Google Patents
Phase-change storage unit with low power consumption and high stability and preparation method thereof Download PDFInfo
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- CN101752497B CN101752497B CN200910201171XA CN200910201171A CN101752497B CN 101752497 B CN101752497 B CN 101752497B CN 200910201171X A CN200910201171X A CN 200910201171XA CN 200910201171 A CN200910201171 A CN 200910201171A CN 101752497 B CN101752497 B CN 101752497B
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Abstract
The invention provides a phase-change storage unit with low power consumption and high stability, comprising a substrate layer, a phase-change material area, an electrode and a dielectric material coating layer which coats the whole phase-change material area, wherein the dielectric material coating layer is made of a material which is not reacted with a phase-change material, the phase-change material of the phase-change material area is a pure phase-change material, or a doped material formed by the phase-change material or a dielectric material, or a composite material formed by the phase-change material and the dielectric material, and the like. The invention also provides a method for preparing the phase-change storage unit with low power consumption and high stability, and the formed phase-change storage unit can effectively restrict elements in the phase-change material, is beneficial to stabilizing the material performance, and simultaneously restricts crystals of the phase-change material from growing up, promotes the resistance ratio of the material, and reduces the power consumption of components.
Description
Technical field
The present invention relates to a kind of phase-change memory cell and preparation method, particularly a kind of phase-change memory cell of low-power consumption high stability and preparation method.
Background technology
Existing multiple semiconductor memory technologies comprises conventional volatibility technology and non-volatile technology at present, wherein, adopt the memory such as the static random access memory (SRAM) of conventional volatibility technology, dynamic random access memory (DRAM) etc., adopt the memory such as the ferroelectric random memory (FeRAM) of non-volatile technology, Electrically Erasable Read Only Memory (EEPROM), flash memory (FLASH) etc., and phase transition storage (C-RAM) is as a kind of emerging semiconductor memory, compare with aforesaid various semiconductor memory technologies, have non-volatile, have extended cycle life (＞10
13Inferior), component size is little, low in energy consumption, can multistagely store, read at a high speed, anti-irradiation, high-low temperature resistant (55-125 ℃), anti-vibration, anti-electronic jamming and manufacturing process plurality of advantages such as simple (can and prior integrated circuit process be complementary).
Existing phase transition storage (C-RAM) is storage medium with the chalcogenide compound, utilize electric energy (heat) to make material transform writing and wiping of realization information mutually between crystalline state (low-resistance) and amorphous state (high resistant), reading of information relies on the variation of measuring resistance to realize.In C-RAM research and development, be to improve one of key technology of C-RAM device performance as the research and development of the phase-change material of memory media and the lifting of performance.In C-RAM, be germanium antimony tellurium alloy (Ge-Sb-Te) at present with more phase-change material, wherein Te is a kind of element of very easy volatilization, report through after the read-write operation repeatedly, Te content in the material reduces, thereby cause the change of device material component, and then influence the stable of device performance.So the volatilization of each element is very important to keep the stable of device performance in the restriction phase-change material.
On the other hand, in the process of phase-change material crystallization, the crystal grain of phase-change material constantly increases, and growing up of phase-change material crystal grain is the resistance main reasons for decrease, so the restriction of grain size is had important meaning to the lifting of memory data confining force.In addition, the trend that size is constantly dwindled in bigger crystal grain and the research and development of current phase transition storage is contradiction, and the appearance of big crystal grain has negative influence for the reliability of C-RAM device.So in highdensity C-RAM, should avoid the appearance of big crystal grain as far as possible, it is the problem that must face in the middle of the present C-RAM research and development that the size that effectively reduces phase-change material crystal grain makes it be fit to the following semiconductor process techniques of 90nm more.
Summary of the invention
The object of the present invention is to provide a kind of phase-change memory cell and preparation method of low-power consumption high stability.
Reach other purposes in order to achieve the above object, the phase-change memory cell of a kind of low-power consumption high stability provided by the invention, comprise basalis, phase-change material district, electrode and with the whole dielectric material coating layers of parcel in described phase-change material district, and the material of the material of described dielectric material coating layer for not reacting with described phase-change material.
Preferable, the material of described dielectric material coating layer can be Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more; Its thickness is 2-6nm.
In addition, the phase-change material in described phase-change material district can be the dopant material of phase-change material and dielectric material formation, perhaps is the composite material that phase-change material and dielectric material constitute.
The phase-change memory cell of another kind of low-power consumption high stability provided by the invention, comprise basalis, phase-change material layers and electrode, wherein, described phase-change material layers is the doped layer that phase-change material and dielectric material constitute, perhaps be the composite bed that phase-change material and dielectric material constitute, the material of described dielectric material for not reacting with described phase-change material.
Preferable, described dielectric material can be Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more.
In addition, the present invention also provides a kind of method for preparing the phase-change memory cell of low-power consumption high stability, comprises step: 1) prepare electrode layer and insulating barrier successively on Semiconductor substrate, and etch the zone that needs to form phase-change material layers on described insulating barrier; 2) form a dielectric material film in the described zone that needs to form phase-change material layers; 3) form the phase-change material district at described dielectric material film surface; 4) form an insulating barrier again at the body structure surface that forms the phase-change material district, and the described insulating barrier of etching is to expose described phase-change material district; 5) form a dielectric material film again on the surface, phase-change material district that is exposed, formed dielectric material film and step 2) in formed dielectric film constitute one with the whole dielectric material coating layers of parcel in phase-change material district; And 6) on the structure that forms the dielectric material coating layer, make electrode.
Wherein, the material of described dielectric material coating layer is Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more; The thickness of dielectric material film is 2-6nm; Can adopt a kind of formation dielectric material film and phase-change material district in sputtering method, chemical vapour deposition technique, pulsed laser deposition method, sol-gel process, the ion implantation.
In addition, the phase-change material in described phase-change material district can be the dopant material of phase-change material and dielectric material formation, perhaps is the composite material that phase-change material and dielectric material constitute.
In sum, the phase-change memory cell of low-power consumption high stability of the present invention and preparation method wrap up phase-change material by adopting dielectric material, can improve the thermal stability of material, reduce the power consumption in the device phase transition process, under the situation that does not change device architecture, can boost device stability, performance such as data holding ability.
Description of drawings
Fig. 1 to Figure 10 is the phase-change memory cell preparation method schematic flow sheet of low-power consumption high stability of the present invention.
Embodiment
Embodiment one:
See also Fig. 1 to Figure 10, the phase-change memory cell of low-power consumption high stability of the present invention comprises at least: by Semiconductor substrate, lower electrode layer, insulating barrier, phase-change material district, dielectric material coating layer and top electrode, wherein, described dielectric material coating layer joint all wraps up the phase-change material district, the Si of its material that adopts for not reacting with described phase-change material
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more, thickness is 2-6nm, phase-change material is the material with reversible transition characteristic, as germanium antimony tellurium alloy (Ge-Sb-Te), antimony tellurium alloy (Sb-Te), germanium antimony alloy (Ge-Sb) or other sulfur series compound phase-change material etc.
Below to utilize magnetron sputtering to be equipped with Si
3N
4Dielectric material parcel Ge
2Sb
2Te
5Phase change material unit is the method that example describes the phase-change memory cell of preparation low-power consumption high stability of the present invention in detail.
1) clean the Semiconductor substrate (as silicon substrate) that (100) are orientated, the thick tungsten electrode 2 (being bottom electrode) of preparation 100nm on silicon substrate 1, as shown in Figure 1.
2) depositing silicon oxide layer deposited 3 on the substrate of tungsten electrode (being insulating barrier), thickness is 100nm, as shown in Figure 2.
3) utilize exposure-etching technics silicon oxide layer 3 (on carve the zone of diameter 200nm, as the zone of needs formation phase-change material layers, the exposure method of employing is an electron beam exposure, and lithographic method is a reactive ion etching, as shown in Figure 3.
4) zone that needs to form phase-change material layers on silicon substrate 1 prepares one deck Si
3N
4 Dielectric material film 4, thickness are the 2-6 nanometer, and structure as shown in Figure 4.
5) at Si
3N
4Prepare Ge on the dielectric material film 4
2Sb
2Te
5Phase-change material district 5, structure as shown in Figure 5.Utilize sputtering method to adopt Ge
2Sb
2Te
5Alloys target prepares Ge
2Sb
2Te
5Film.In the preparation process, base vacuum is less than 10
-5Pa, the ar pressure during sputter are 0.2Pa, sputtering power: be added in Ge
2Sb
2Te
5On the alloys target is 50 watts of direct currents, and sputtering time is 15 minutes, and deposit thickness is roughly 180nm.
6) depositing Ge
2Sb
2Te
5Silicon oxide layer deposited 6 on the substrate in phase-change material district 5, and thickness is 2-6nm, as shown in Figure 6.
7) utilize exposure-etching technics to carve the zone of diameter 200nm on silicon oxide layer 6, the exposure method of employing is an electron beam exposure, and lithographic method is a reactive ion etching, and structure as shown in Figure 7.
8) depositing Ge
2Sb
2Te
5Deposition one deck Si on the substrate in phase-change material district 5
3N
4 Dielectric material film 7, thickness is the 2-6 nanometer, makes Si
3N
4 Dielectric material film 7 and Si
3N
4 Dielectric material film 4 constitutes Ge
2Sb
2Te
5Phase-change material district 5 is the dielectric material coating layer of parcel all, and structure as shown in Figure 8.
9) depositing phase-change material district 5 and Si
3N
4Deposition 300nm aluminium electrode 8 on the substrate of dielectric material coating layer, as shown in Figure 9.
10) utilizing exposure-etching technics that part aluminium electrode is carved again goes, prepare top electrode, thereby form the C-RAM unit component, as shown in figure 10, it can be used as the function element of storage, also can be used as the component units of the chalcogenide compound random asccess memory of employing electric pulse programming, also can be used as the component units of the stored CD of employing laser pulse programming or memory that the employing electron beam is programmed or the memory that adopts other energy particle programming etc.
11) the C-RAM unit component is carried out electrical performance testing with clock.Above-mentioned means of testing is used for weighing the phase-change characteristic of material, comprises structure, threshold current and the dopant material distribution in material of phase transition temperature, crystallization activation energy, phase transformation front and back.
Need to prove that the preparation in dielectric material plate film and phase-change material district is not to exceed with sputtering method, for example also can adopt chemical vapour deposition technique, pulsed laser deposition method, sol-gel process or ion implantation or the like.Dielectric material also can adopt Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, or CeO
2Or the like, phase-change material also can adopt antimony tellurium alloy (Sb-Te), germanium antimony alloy (Ge-Sb) or other sulfur series compound phase-change material etc., also can be the dopant material that phase-change material and dielectric material constitute, perhaps be the composite material that constitutes of phase-change material and dielectric material etc., in this explanation no longer one by one.
Embodiment two:
The phase-change memory cell of low-power consumption high stability of the present invention comprises at least: basalis, phase-change material layers and upper/lower electrode etc. that semi-conducting material constitutes, wherein, described phase-change material layers is the doped layer that phase-change material and dielectric material constitute, it perhaps is the composite bed that phase-change material and dielectric material constitute, the material of described dielectric material for not reacting with described phase-change material, it can be Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more, phase-change material is the material with reversible transition characteristic, as germanium antimony tellurium alloy (Ge-Sb-Te), antimony tellurium alloy (Sb-Te), germanium antimony alloy (Ge-Sb) or other sulfur series compound phase-change material etc.
Its preparation method is: at first adopt a kind of preparation layer of dielectric material in sputtering method, chemical vapour deposition technique, pulsed laser deposition method, sol-gel process or the ion implantation, phase-change material layers, layer of dielectric material, metal level etc. in regular turn on Semiconductor substrate (as the silicon substrate of (100) orientation), make electrode etc. at last.
In sum, phase-change memory cell of low-power consumption high stability of the present invention and preparation method thereof is wrapped in phase-change material wherein by adopting dielectric material, can suppress the volatilization of phase-change material, keep the stable of phase-change material component, thereby keep the reliable and stable of device performance.On the other hand,, can improve the efficiency of heating surface, reduce device power consumption because dielectric material has bigger resistivity and less thermal conductivity.Simultaneously because dielectric material is isolated into the zone of nano-scale with phase-change material, phase-change material crystal grain is not easy to grow up, and has suppressed further crystallization, has reduced resistivity decrease speed in time, has promptly promoted data holding ability.
The foregoing description just lists expressivity principle of the present invention and effect is described, but not is used to limit the present invention.Any personnel that are familiar with this technology all can make amendment to the foregoing description under spirit of the present invention and scope.Therefore, the scope of the present invention should be listed as claims.
Claims (5)
1. the phase-change memory cell of a low-power consumption high stability, comprise basalis, phase-change material district and electrode, it is characterized in that also comprising: with the whole dielectric material coating layers of parcel in described phase-change material district, and the material of the material of described dielectric material coating layer for not reacting with described phase-change material.
2. the phase-change memory cell of low-power consumption high stability as claimed in claim 1 is characterized in that: the material of described dielectric material coating layer is Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more.
3. the phase-change memory cell of low-power consumption high stability as claimed in claim 1 or 2 is characterized in that: the thickness of described dielectric material coating layer is 2-6nm.
4. method for preparing the phase-change memory cell of low-power consumption high stability is characterized in that comprising step:
1) on Semiconductor substrate, prepares electrode layer and insulating barrier successively, and on described insulating barrier, etch the zone that needs to form phase-change material layers;
2) form a dielectric material film in the described zone that needs to form phase-change material layers;
3) form the phase-change material district at described dielectric material film surface;
4) form an insulating barrier again at the body structure surface that forms the phase-change material district, and the described insulating barrier of etching is to expose described phase-change material district;
5) form a dielectric material film again on the surface, phase-change material district that is exposed, formed dielectric material film and step 2) in formed dielectric film constitute one with the whole dielectric material coating layers of parcel in phase-change material district;
6) on the structure that forms the dielectric material coating layer, make electrode.
5. the method for the phase-change memory cell of preparation low-power consumption high stability as claimed in claim 4 is characterized in that: the material of described dielectric material coating layer is Si
3N
4, Ge
3N
4, HfO
2, Ta
2O
5, TiO
2, CeO
2In one or more.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102117883B (en) * | 2010-01-05 | 2014-05-21 | 同济大学 | Method for reducing power consumption of unit operation of phase change memory |
| CN102376877A (en) * | 2010-08-05 | 2012-03-14 | 中芯国际集成电路制造(上海)有限公司 | Phase change memory and forming method thereof |
| CN101931049B (en) * | 2010-08-31 | 2012-11-14 | 中国科学院上海微系统与信息技术研究所 | Anti-fatigue phase change storage unit with low power consumption and preparation method thereof |
| CN102082228A (en) * | 2010-10-14 | 2011-06-01 | 中国科学院上海微系统与信息技术研究所 | Nano compound phase-change material and application thereof to phase-change storage |
| CN102169958B (en) * | 2011-04-29 | 2013-07-10 | 中国科学院上海微系统与信息技术研究所 | Nanocomposite phase-change material, preparation method and application thereof in phase-change memory |
| CN103531709B (en) * | 2012-07-02 | 2015-12-09 | 中芯国际集成电路制造(上海)有限公司 | Phase transition storage and preparation method thereof |
| CN103682089A (en) * | 2012-09-11 | 2014-03-26 | 中国科学院上海微系统与信息技术研究所 | High-speed, high-density and lower power consumption phase-change memory unit and preparation method thereof |
| CN104810475B (en) * | 2015-04-02 | 2018-01-23 | 宁波大学 | A kind of nanometer composite Ti O2‑Sb2Te phase transiting storing thin-film materials and preparation method thereof |
| CN110571331B (en) * | 2019-08-30 | 2021-01-01 | 华中科技大学 | Stress-resistant superlattice phase change memory cell, preparation method thereof and phase change memory |
| CN112133825A (en) * | 2020-09-03 | 2020-12-25 | 中国科学院上海微系统与信息技术研究所 | High-stability phase change storage unit and preparation method thereof |
| CN113241405B (en) * | 2021-04-14 | 2023-04-25 | 华中科技大学 | Method for inducing crystallization of chalcogenide phase change material and application thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101320783A (en) * | 2007-06-05 | 2008-12-10 | 财团法人工业技术研究院 | Phase variation memory |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101320783A (en) * | 2007-06-05 | 2008-12-10 | 财团法人工业技术研究院 | Phase variation memory |
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