CN103227283A - Self-rectification RRAM based on TaOx and preparation method of RRAM - Google Patents

Self-rectification RRAM based on TaOx and preparation method of RRAM Download PDF

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CN103227283A
CN103227283A CN201310141859XA CN201310141859A CN103227283A CN 103227283 A CN103227283 A CN 103227283A CN 201310141859X A CN201310141859X A CN 201310141859XA CN 201310141859 A CN201310141859 A CN 201310141859A CN 103227283 A CN103227283 A CN 103227283A
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tao
electrode
hearth electrode
top electrode
self
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CN103227283B (en
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黄如
余牧溪
蔡一茂
黄英龙
白文亮
方亦陈
黎明
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Peking University
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Abstract

The invention relates to a self-rectification RRAM (Resistive Random Access Memory) based on TaOx and a preparation method of the RRAM. The preparation method comprises the steps that 1) a bottom electrode is prepared at a substrate, and a bottom electrode graph is formed through photoengraving; 2) n<+>/p<+> heavy doping is conducted on a bottom electrode graph area to form the bottom electrode; 3) a TaOx film is prepared on the bottom electrode, and a material of a top electrode is selected according to the doping type of the bottom electrode and the range of a TaOx impurity energy level; and 4) the top electrode is sputtered and patterned on an oxide film; the preparation is completed; and the RRAM that the patterned substrate part is the bottom electrode formed by n<+>/p<+> heavy doping treatment, and a schottky contact surface and an ohmic contact surface are arranged on a resistive random film between the top electrode and the bottom electrode is obtained. According to the self-rectification RRAM and the preparation method, the RRAM bottom electrode based on TaOx is prepared by adopting heavily doped Si, the top electrode is selected reasonably, and an appropriate operation method is adopted, so that the self-rectification memory that is suitable for superintegration and is fully compatible with a CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology is achieved.

Description

Based on TaO xSelf-rectifying resistance-variable storing device and preparation method thereof
Technical field
The present invention relates to resistance-variable storing device (RRAM), be specifically related to a kind of superintegrated self-rectifying TaO compatible fully that be applicable to CMOS technology xResistance-variable storing device and preparation method thereof belongs to the novel memory construction of nonvolatile memory (Nonvolatile memory) in the cmos vlsi (ULSI), manufacturing technology and preparation method thereof technical field.
Background technology
Along with microelectronic age advances to the nano-electron epoch gradually, the non-volatility memorizer Flash of main flow is also constantly carrying out structure and technologic improvement at present, in the hope of obtaining more dominance energy of smaller szie.But after entering the nano-scale node, the scaling of Flash will reach physics limit, and the random fluctuation of its parameter significantly increases simultaneously, and integrity problem is increasingly serious.Face this challenge, people are based on new material, new construction and the new multiple innovative design of function, the non-volatility memorizer technical solution is constantly proposed, comprise charge trap memory (CTM), ferroelectric memory (FeRAM), magnetic memory (MRAM), phase transition storage (PRAM), resistance-variable storing device etc.Wherein, RRAM relies on the excellent memory property of its each side, and especially its huge size is dwindled potential quality, has obtained people's extensive concern; In recent years, become the general research focus of memory industry especially.
The memory property of excellences such as RRAM has significant scaling advantage, and simultaneously RRAM also has the on-off ratio height, operating voltage is low, power consumption is little, durability and retention performance are good.But RRAM does not carry out extensive integrated production yet so far, reason is mainly reflected in two aspects: with regard to RRAM itself, its independent when integrated because the adjacent devices more serious cross-interference issue of less common existence at interval, old friends often adopt the integrated morphology of 1T1R or 1D1R, integration density just depends on selection pipe T or the diode D that area is bigger like this, integration density is reduced and has weakened the scaling advantage of RRAM greatly; On the other hand, at present the RRAM hearth electrode generally adopts the precious metals pt of stable performance, and Pt costs an arm and a leg, and is difficult to dry etching and has relatively poor adhesiveness and be unfavorable for that technology is integrated.So people's expectation finds the hearth electrode material of suitable process compatible to substitute Pt, thereby optimizes manufacture craft greatly.The present invention promptly is primarily aimed at above two aspect problems and proposes solution.
The resistive characteristic that RRAM is based on storage medium realizes information stores, the resistive characteristic be exist in some dielectric substance the character of reversible variation between high low resistance state takes place at resistance under the extra electric field effect.Material with resistive characteristic is a lot, and wherein transition metal oxide (TMO) occupies main flow because it is simple in structure.And among the TMO-RRAM, based on TaO xRRAM because its significant wear properties (〉 10 12) and stable performance and receiving much concern.
Summary of the invention
Based on above content, the present invention adopts heavy doping Si to do based on TaO xThe RRAM hearth electrode, and choose reasonable top electrode and adopt suitable method of operation realizes being applicable to the superintegrated self-rectifying memory compatible fully with CMOS technology.
The present invention mainly discusses based on TaO xRRAM structure and manufacturing.As shown in Figure 1.
Based on TaO xRRAM resistive mechanism be commonly considered as conductive filament (CF) mechanism.Be that forming operates in TaO xThe middle conductive filament (CF) that forms, RRAM becomes low resistance state (LRS), and the reset operation makes CF break at oxide and electrode interface place, and RRAM becomes high-impedance state (HRS), the part that the set operation then makes CF interrupt connects again, and RRAM comes back to low-resistance (LRS).Can be by set and reset operation to the RRAM writing information.The present invention considers the contact berrier of conductive filament (CF) and top electrode (TE) and hearth electrode (BE): because conductive filament (CF) is equivalent to the TaO of oxygen room (Vo) defect doping xSo, can rationally regulate TaO xThe relative position of defect level and top electrode/hearth electrode Fermi level promptly can obtain a stable Schottky contacts face and an ohmic contact face, obtains the self-rectification effect of RRAM, thereby effectively suppresses the crossfire of high density when integrated.
Technical scheme of the present invention is as follows:
A kind of based on TaO xThe self-rectifying resistance-variable storing device, comprise the resistive film between top electrode, hearth electrode, substrate and top electrode and hearth electrode, described hearth electrode has a Schottky contacts face and an ohmic contact face for the substrate part after handling through graphical and n+/p+ heavy doping in two contact-making surfaces between described resistive film and top electrode and hearth electrode.
Further, described hearth electrode is heavy doping Si.
Further, top electrode and hearth electrode form right-angled intersection, and right-angled intersection partly is the crossbar resistance variation memory structure.
Alternatively, to p+ heavy doping Si hearth electrode, select top electrode material workfunction range near TaO xThe top electrode material of impurity energy level, to n+ heavy doping Si hearth electrode, the top electrode material selects work function at TaO xThe extraneous top electrode material of impurity energy level.
Alternatively, to p+ heavy doping Si hearth electrode, top electrode select for use following one or more: Pt, Ir, Ni, to n+ heavy doping Si hearth electrode, top electrode select for use following one or more: TiN, Ti, Ag, described resistive thin-film material is TaO x
The present invention also proposes a kind of based on TaO xSelf-rectifying resistance-variable storing device preparation method, comprising:
1), forms the hearth electrode figure by photoetching at the substrate preparation hearth electrode;
2) heavy doping of n+/p+ ion is carried out in described hearth electrode graphics field and form hearth electrode;
3) on hearth electrode, prepare TaO xFilm is according to the doping type and the TaO of hearth electrode xThe impurity energy level scope is selected the top electrode material;
4) sputter and graphical top electrode on oxide film are finished preparation.
Further, described substrate is the Si sheet, deposit SiO on the Si sheet 2As the photoetching corrosion protective layer.
Further, the SiO of corrosion hearth electrode graphics field 2Protective layer forms heavy doping Si hearth electrode in the hearth electrode zone, prepares TaO by the PVD sputtering method again xThe resistive material film.
Further, adopt PVD sputter preparation and photolithography patterning top electrode.
Further, to p+ heavy doping Si hearth electrode, top electrode select for use following one or more: Pt, Ir, Ni, to n+ heavy doping Si hearth electrode, top electrode select for use following one or more: TiN, Ti, Ag, described resistive thin-film material TaO xFilm.
Beneficial effect of the present invention
The present invention has designed a kind of based on TaO xThe self-rectifying resistance-variable storing device, the hearth electrode material is wished the material that adopting process is compatible high, price is low, conductance is high, stability is high, adopts heavy doping Si to do based on TaO here xThe RRAM hearth electrode, and choose reasonable top electrode and adopt suitable method of operation realizes being applicable to the superintegrated self-rectifying memory compatible fully with CMOS technology.When RRAM is carried out electrical operation, should be little current practice, guarantee the Schottky Barrier Contact of conductive filament (CF) and a certain electrode.
Description of drawings
Fig. 1 is based on TaO in the prior art xRRAM resistive structural representation, wherein, silicon substrate 1 ', protective layer 2 ', hearth electrode 3 ', resistive material film 4 ', top electrode 5 ';
Fig. 2 the present invention is based on TaO xThe resistance variation memory structure schematic diagram;
Fig. 3 is the shape schematic diagram of crossbar resistance-variable storing device top electrode of the present invention and hearth electrode;
Fig. 4 is top electrode in one embodiment of the invention, Ta 2O 5, being with of hearth electrode Si concern schematic diagram;
Fig. 5 is a hearth electrode pictorial diagram in one embodiment of the invention;
Fig. 6 is the schematic diagram that one embodiment of the invention intermediate ion injects;
Fig. 7 is a heavy doping Si hearth electrode schematic diagram in one embodiment of the invention;
Fig. 8 is a preparation resistive film schematic diagram in one embodiment of the invention;
Fig. 9 is a preparation top electrode schematic diagram in one embodiment of the invention;
Wherein, silicon substrate 1, protective layer 2, heavy doping Si hearth electrode 3, resistive material film 4, top electrode 5.
Specific embodiments
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, be understandable that described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those skilled in the art belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
A kind of based on TaO xResistance-variable storing device, its structure chart is as shown in Figure 2; The shape schematic diagram of its top electrode and hearth electrode as shown in Figure 3.
Fig. 2 specifically describes as follows:
On the Si substrate, determined the hearth electrode figure, the Si substrate has been carried out n+/p+ heavy doping handle, formed hearth electrode by photoetching.Preparing even sputter one deck TaO on the Si substrate of hearth electrode xMake the resistive material.Again at TaO xSputter and graphical top electrode on the change resistance layer.
Fig. 3 specifically describes as follows:
The part of top electrode and hearth electrode right-angled intersection is modal crossbar resistance variation memory structure.Resistance-variable storing device prepared flow process of the present invention is as follows:
(1) hearth electrode preparation, deposit one deck SiO on substrate 2, photoetching forms hearth electrode figure, SiO 2Make protective layer, carry out the n+/p+ ion to the hearth electrode visuals and inject heavy doping, form hearth electrode;
(2) resistive film preparation prepares TaO by sputtering method xFilm;
(3) top electrode preparation, sputter preparation and graphical top electrode, definition device size.
Material of the present invention is selected explanation and resistive operating instruction:
(1) the hearth electrode material that wish to find the processing compatibility height among the present invention, price is low, conductance is high, stability is high is taken all factors into consideration the material ranges that the standard CMOS integrated technique relates to, and heavily doped Si promptly is a best choice.
(2) wish among the present invention that conductive filament (CF) and upper/lower electrode form a stable Schottky contacts face and an ohmic contact face, consider top electrode, Ta 2O 5, hearth electrode Si can be with relation, (TaO as shown in Figure 4 xEnergy band diagram changes with x, so with Ta 2O 5Band structure is determined the potential barrier scope).
Because conductive filament (CF) is equivalent to the TaO of oxygen room (Vo) defect doping x, promptly be equivalent to the TaO that the n type mixes xSo the impurity energy level scope is Ta 2O 5Arrive forbidden band central authorities at the bottom of the conduction band, and the Fermi level of n+/p+ heavy doping Si can be used respectively at the bottom of the conduction band of Si and the top of valence band equivalence, thereby calculate n+ heavy doping Si and TaO xForm the potential barrier scope of Schottky barrier: be 0～0.12eV, and the corresponding potential barrier scope of p+ heavy doping Si: 0～1.21eV.Be the easy and TaO of p+ heavy doping Si xChange resistance layer form potential barrier and n+ heavy doping Si easily and TaO xChange resistance layer forms ohmic contact.
In view of above analysis, when selecting the top electrode material, emphasis is considered the work function of top electrode material.For p+ heavy doping Si hearth electrode, select the top electrode material (as TiN:4.5eV, Ti:4.34eV, Ag:4.26eV etc.) of workfunction range maximum possible, in the hope of forming ohmic contact near impurity energy level as far as possible; And, can select work function to drop on the extraneous top electrode material of impurity energy level (as Pt:5.65eV, Ir:5.27eV, Ni:5.15eV etc.) for n+ heavy doping Si hearth electrode, make it form Schottky contacts.So just, can realize TaO xThe self-rectifying function of resistance-variable storing device.
(3) TaO among the present invention xThe conductive filament (CF) that middle oxygen room forms, if oxygen room doping content is too high, even if then there is potential barrier to exist, CF also tends to form ohmic contact with electrode in the zone.So when RRAM is carried out electrical operation, should be little current practice, promptly control oxygen room doping content in the conductive filament (CF), guarantee the Schottky Barrier Contact of itself and a certain electrode.
Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:
The present invention's preparation is applicable to the superintegrated self-rectifying TaO compatible fully with CMOS technology xThe technology of resistance-variable storing device is described below in conjunction with the accompanying drawings:
1) definition top electrode figure.Deposit SiO on silicon substrate 1 2As protective layer 2, carry out the photoetching first time, form the hearth electrode figure, (the about 300nm of protective layer thickness) as shown in Figure 5;
2) ion injects.Whole silicon wafer is carried out the n+/p+ ion inject heavy doping, as shown in Figure 6;
3) preparation hearth electrode.Corrosion SiO 2Protective layer, at this moment on the Si substrate not by the SiO2 protection zone, promptly the hearth electrode zone of definition forms heavy doping Si hearth electrode 3, as shown in Figure 7;
4) preparation resistive film.Prepare TaO by the PVD sputtering method x Resistive material film 4, (thickness is greatly about 20～50nm) as shown in Figure 8;
5) preparation top electrode.PVD sputter preparation and graphical top electrode 5, definition device size scope (2 μ m * 2 μ m～100 μ m * 100 μ m) as shown in Figure 9, makes TaO xResistance-variable storing device.

Claims (10)

1. one kind based on TaO xThe self-rectifying resistance-variable storing device, comprise the resistive film between top electrode, hearth electrode, substrate and top electrode and hearth electrode, it is characterized in that, described hearth electrode has a Schottky contacts face and an ohmic contact face for the substrate part after handling through graphical and n+/p+ heavy doping in two contact-making surfaces between described resistive film and top electrode and hearth electrode.
2. as claimed in claim 1 based on TaO xThe self-rectifying resistance-variable storing device, it is characterized in that described hearth electrode is heavy doping Si.
3. as claimed in claim 1 based on TaO xThe self-rectifying resistance-variable storing device, it is characterized in that top electrode and hearth electrode form right-angled intersection, right-angled intersection partly is the crossbar resistance variation memory structure.
As claim 2-3 any one described based on TaO xThe self-rectifying resistance-variable storing device, it is characterized in that, to p+ heavy doping Si hearth electrode, select top electrode material workfunction range near TaO xThe top electrode material of impurity energy level, to n+ heavy doping Si hearth electrode, the top electrode material selects work function at TaO xThe extraneous top electrode material of impurity energy level.
As claim 2-3 any one described based on TaO xThe self-rectifying resistance-variable storing device, it is characterized in that,
To p+ heavy doping Si hearth electrode, top electrode select for use following one or more: Pt, Ir, Ni, to n+ heavy doping Si hearth electrode, top electrode select for use following one or more: TiN, Ti, Ag, described resistive thin-film material is TaO x
6. one kind based on TaO xSelf-rectifying resistance-variable storing device preparation method, comprising:
1), forms the hearth electrode figure by photoetching at the substrate preparation hearth electrode;
2) heavy doping of n+/p+ ion is carried out in described hearth electrode graphics field and form hearth electrode;
3) on hearth electrode, prepare TaO xFilm is according to the doping type and the TaO of hearth electrode xThe impurity energy level scope is selected the top electrode material;
4) sputter and graphical top electrode on oxide film are finished preparation.
7. as claimed in claim 6 based on TaO xSelf-rectifying resistance-variable storing device preparation method, it is characterized in that described substrate is the Si sheet, deposit SiO on the Si sheet 2As the photoetching corrosion protective layer.
8. as claimed in claim 7 based on TaO xSelf-rectifying resistance-variable storing device preparation method, it is characterized in that the SiO of corrosion hearth electrode graphics field 2Protective layer forms heavy doping Si hearth electrode in the hearth electrode zone, prepares TaOx resistive material film by the PVD sputtering method again.
9. as claimed in claim 6 based on TaO xSelf-rectifying resistance-variable storing device preparation method, it is characterized in that, adopt PVD sputter preparation and photolithography patterning top electrode.
10. as claimed in claim 6 based on TaO xSelf-rectifying resistance-variable storing device preparation method, to p+ heavy doping Si hearth electrode, top electrode select for use following one or more: Pt, Ir, Ni, to n+ heavy doping Si hearth electrode, top electrode select for use following one or more: TiN, Ti, Ag, described resistive thin-film material TaO xFilm.
CN201310141859.XA 2013-04-22 2013-04-22 Self-rectification RRAM based on TaOx and preparation method of RRAM Active CN103227283B (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105552219A (en) * 2015-12-10 2016-05-04 上海交通大学 RRAM memory cell structure with self-rectification characteristic and preparation method thereof
CN106025066A (en) * 2016-06-02 2016-10-12 河北大学 Silicon dioxide tunnel junction based resistive random access memory and preparation method therefor
CN108933194A (en) * 2017-05-24 2018-12-04 中国科学院物理研究所 A kind of memristor and preparation method thereof based on schottky junction modulation
WO2023216437A1 (en) * 2022-05-08 2023-11-16 浙江大学 On current-programmable diode device and array preparation methods thereof

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Publication number Priority date Publication date Assignee Title
CN102017146A (en) * 2008-05-01 2011-04-13 分子间公司 Non-volatile resistive-switching memories
CN102214790A (en) * 2011-06-10 2011-10-12 清华大学 Resistive random access memory with self-rectifying effect
US8072795B1 (en) * 2009-10-28 2011-12-06 Intermolecular, Inc. Biploar resistive-switching memory with a single diode per memory cell

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102017146A (en) * 2008-05-01 2011-04-13 分子间公司 Non-volatile resistive-switching memories
US8072795B1 (en) * 2009-10-28 2011-12-06 Intermolecular, Inc. Biploar resistive-switching memory with a single diode per memory cell
CN102214790A (en) * 2011-06-10 2011-10-12 清华大学 Resistive random access memory with self-rectifying effect

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105552219A (en) * 2015-12-10 2016-05-04 上海交通大学 RRAM memory cell structure with self-rectification characteristic and preparation method thereof
CN106025066A (en) * 2016-06-02 2016-10-12 河北大学 Silicon dioxide tunnel junction based resistive random access memory and preparation method therefor
CN106025066B (en) * 2016-06-02 2018-11-20 河北大学 A kind of resistance-variable storing device and preparation method thereof based on silicon dioxide tunnel knot
CN108933194A (en) * 2017-05-24 2018-12-04 中国科学院物理研究所 A kind of memristor and preparation method thereof based on schottky junction modulation
WO2023216437A1 (en) * 2022-05-08 2023-11-16 浙江大学 On current-programmable diode device and array preparation methods thereof

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