CN102800805B - Phase change storage unit and forming method thereof - Google Patents
Phase change storage unit and forming method thereof Download PDFInfo
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- CN102800805B CN102800805B CN201110136665.1A CN201110136665A CN102800805B CN 102800805 B CN102800805 B CN 102800805B CN 201110136665 A CN201110136665 A CN 201110136665A CN 102800805 B CN102800805 B CN 102800805B
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Abstract
The embodiment of the invention provides a phase change storage unit. The phase change storage unit comprises a diode, at least four discrete bottom electrodes electrically connected with the diode, and phase change units electrically connected with the bottom electrodes in a one-to-one corresponding way. The phase change storage unit provided by the embodiment of the invention contains a large diode in a space which is used for containing a plurality of diodes in the prior art, wherein the big diode corresponds to a plurality of phase change units. As the cross sectional area of the big diode is enlarged, high driving current can be provided, and the driving capability of the diode is enhanced so as to meet the needs of the storage function, and the forming process of the phase change storage unit provided by the embodiment of the invention is simple.
Description
Technical field
The present invention relates to technical field of manufacturing semiconductors, particularly relate to a kind of phase-change memory cell and forming method thereof.
Background technology
Phase transition storage (Phase Change Random Access Memory, PCRAM) technology is that the conception that can be applied to phase change memory medium at late 1960s proposition phase-change thin film based on S.R.Ovshinsky is set up.As a kind of emerging nonvolatile storage technologies, phase transition storage all has larger superiority in all many-sides such as read or write speed, read-write number of times, data hold time, cellar area, many-valued realizations to flash memory, has become the focus of current non-volatile memory technology research.
In prior art, phase transition storage can by applying different voltage or electric current selects specific phase-change memory cell, thus complete read-write and wipe operation.Phase transition storage comprises peripheral circuit and memory areas, described memory areas comprises multiple phase-change memory cell, please refer to Fig. 1, described phase-change memory cell generally includes a diode 100 and a phase change cells 105, the material of described phase change cells 105 is phase-change material such as Ge-Sb-Te, hereinafter referred to as GST.Under certain condition, can there is reversible phase transformation in described phase-change material between crystalline and amorphous.Described phase transition storage controls the switch of phase-change memory cell by diode 100, when diode 100 is in conducting state, electric current is by conductive plug 101, hearth electrode 103, phase change cells 105 and top electrode 107, reversible transition can be there is between crystalline and amorphous in described phase change cells 105, any one in described two states is designated as logical one, another is designated as logical zero, setting becomes the function that the electrical state that can reset can realize storing.
Along with the development of semiconductor fabrication process, the size scaled down of device, the advantage of phase transition storage is more and more obvious, but along with the scaled down of device size, its drive current, also by scaled down, is difficult to the demand of the memory function meeting phase transition storage.For meeting the demand of the memory function of phase transition storage, usually need the diode with higher current drive capability, or the drive current that reduction realizes needed for phase transition storage memory function.Said method is not still well positioned to meet the demand of the memory function of phase transition storage.
The formation method of more heterogeneous transition storage please refer to the United States Patent (USP) that the patent No. is " US6838727B2 ".
Summary of the invention
The problem that the present invention solves is to provide and a kind ofly meets phase-change memory cell of the demand of memory function and forming method thereof.
For solving the problem, The embodiment provides a kind of phase-change memory cell, comprising:
Diode;
At least four that are connected with described diode electrically discrete hearth electrodes;
The phase change cells be electrically connected with described hearth electrode one_to_one corresponding.
Alternatively, the material of described phase change cells is Ge-Sb-Te.
Alternatively, the material of described hearth electrode is Ti, TiN, Ta or TaN, and the thickness of described hearth electrode is less than 100
Alternatively, also comprise: the conductive plug that one end is connected with described diode; Base electrode, one end of described base electrode is connected with conductive plug, and the other end is connected with described hearth electrode; The top electrode connected one to one with described phase change cells; The bit line connected one to one with described top electrode.
Embodiments of the invention additionally provide a kind of formation method of phase-change memory cell, comprising:
Diode is provided;
Form be connected with described diode electrically at least four discrete hearth electrodes;
Form the phase change cells be electrically connected with described hearth electrode one_to_one corresponding.
Alternatively, also comprise: form the conductive plug that one end is connected with described diode; Form base electrode, one end of described base electrode is connected with conductive plug, and the other end is connected with described hearth electrode; Form the top electrode connected one to one with described phase change cells; Form the bit line connected one to one with described top electrode.
Alternatively, the forming step of described conductive plug is: form first medium layer at Diode facets, the surface of described first medium layer has third direction and the fourth direction vertical with described third direction; Form photoresist layer on described first medium layer surface, described photoresist layer has opening, and the position of described opening is corresponding with the position of the conductive plug of follow-up formation; With described photoresist layer for first medium layer described in mask etching, form the first groove, described first groove exposes Diode facets; In described first groove, fill full electric conducting material, form conductive plug.
Alternatively, the forming step of described hearth electrode comprises: form the second interlayer dielectric layer being positioned at dielectric layer surface between ground floor, described second interlayer dielectric layer has the first opening, described first opening exposes conductive plug and the first interlayer dielectric layer, and runs through the second interlayer dielectric layer of third direction; Formed and cover the surface of described second interlayer dielectric layer and the hearth electrode film of sidewall and the first interlayer dielectric layer; Form the first stop-layer covering described hearth electrode film; Form the second stop-layer being positioned at described first stop-layer surface, described second stop-layer has the second opening, and described second opening exposes the first stop-layer, and runs through the second stop-layer of fourth direction; Formed be positioned at described second stop-layer surface third layer between dielectric layer, between described third layer, dielectric layer exposes the second opening; With dielectric layer between described third layer and the second stop-layer for mask, remove the second interlayer dielectric layer of the first stop-layer, hearth electrode film and segment thickness; Dielectric layer, the second stop-layer, the first stop-layer and hearth electrode film between third layer described in planarization, after exposing the second interlayer dielectric layer, remove dielectric layer between described third layer, forms base electrode and at least four discrete storage areas.
Alternatively, the forming step of described phase change cells is: form the 4th interlayer dielectric layer covering described first stop-layer surface, the surface of described 4th interlayer dielectric layer flushes with dielectric layer surface between the second layer; Photoresist layer is formed on described 4th interlayer dielectric layer surface, described photoresist layer has opening, the position of described opening is corresponding with the position of the phase change cells of follow-up formation, with described photoresist layer for mask removes hearth electrode film, the second interlayer dielectric layer and the first stop-layer, form the second groove; Full phase-change material is filled in described second groove.
Alternatively, the forming step of described top electrode is: form the top electrode film covering described phase change cells, the second interlayer dielectric layer and the 4th interlayer dielectric layer; Form photoresist layer at described top electrode film surface, the position of described photoresist layer is corresponding with the position of top electrode; With described photoresist layer for mask removes top electrode film, form top electrode.
Alternatively, also comprise: with described photoresist layer for mask removes the first interlayer dielectric layer, the second interlayer dielectric layer, the first stop-layer and the 4th interlayer dielectric layer
Compared with prior art, embodiments of the invention have the following advantages:
The phase-change memory cell of the embodiment of the present invention comprises: diode and at least four phase change cells be connected with described diode electrically.Prior art is for holding the region of at least four diodes in embodiments of the present invention only for holding a diode, therefore the size of the diode of the embodiment of the present invention is greater than the size of diode in prior art, under the condition that the voltage provided at peripheral circuit is identical, the electric current of diode in prior art is greater than through the electric current of the diode of the embodiment of the present invention, the driving force of the diode of the embodiment of the present invention is strengthened, thus meets the demand of the memory function of phase transition storage.
Accompanying drawing explanation
Fig. 1 is the structural representation of the phase-change memory cell of prior art;
Fig. 2 is the structural representation of the phase-change memory cell of the embodiment of the present invention;
Fig. 3 is the partial structurtes schematic diagram of the phase transition storage of the embodiment of the present invention;
Fig. 4 is the schematic flow sheet of the formation method of the phase-change memory cell of one embodiment of the invention;
Fig. 5 ~ Figure 12 is the structural representation of the forming process of the formation method of the phase-change memory cell of one embodiment of the invention.
Embodiment
For enabling above-mentioned purpose, the feature and advantage of embodiments of the invention more become apparent, be described in detail below in conjunction with the embodiment of accompanying drawing to embodiments of the invention.
Set forth a lot of detail in the following description so that fully understand embodiments of the invention, but embodiments of the invention can also adopt other to be different from alternate manner described here to implement, therefore embodiments of the invention are not by the restriction of following public specific embodiment.
Just as described in the background section, in existing phase-change memory cell, a diode corresponds to a phase change cells, along with the scaled down of the size of phase transition storage, the voltage that peripheral circuit is supplied to memory cell is limited, the size of described diode reduces, and the driving force of described diode weakens, and is difficult to the demand meeting memory function.Therefore, need the current drive capability reducing drive current or improve diode to meet the demand of memory function.
According to the operation principle of diode, under same process condition, the cross-sectional area of diode is larger, and its drive current that can provide is also larger.The present inventor finds after research, be used for the space being used for holding multiple diode in prior art holding a large diode, described large diode is corresponding with multiple phase change cells, because the cross-sectional area of described large diode increases, higher drive current can be provided, enhance the driving force of diode, thus meet the demand of memory function.
The inventor of the embodiment of the present invention finds after further research, when the size of phase transition storage reduces further, a diode corresponds to the structure of two phase change cells, it is comparatively limited that the cross-sectional area of diode increases, it is limited that driving force strengthens, and the demand meeting memory function is also more limited.The inventor of the embodiment of the present invention finds after further research, a diode corresponds to the structure of four phase change cells, the cross-sectional area increase of diode is comparatively large, and the ability of diode drive current is comparatively strong, and the phase-change memory cell formation process of this kind of structure is simple.
For the problems referred to above, inventor provide a kind of phase-change memory cell, please refer to Fig. 2, comprising:
Diode 200;
The conductive plug 201 be connected with described diode 200;
The base electrode be connected with described conductive plug 201, described base electrode is connected with at least four symmetrically arranged hearth electrodes 2031,2032,2033,2034;
The phase change cells 2051,2052,2053,2054 connected one to one with described hearth electrode 2031,2032,2033,2034;
The top electrode 2071,2072,2073,2074 connected one to one with described phase change cells 2051,2052,2053,2054.
Wherein, described diode 200 is for controlling the switch of phase-change memory cell.When the electric current that the peripheral circuit of phase-change memory cell provides is greater than the drive current of diode, circuit turn-on, can realize memory function.
Described conductive plug 201 is electrically connected with diode 200, for transmitting the signal that diode 200 obtains.The material of described conductive plug 201 is electric conducting material, such as, one in Cu, W, Al.In an embodiment of the present invention, W elected as by the material of described conductive plug 201.
Consider and need certain gap between phase change cells 2051,2052,2053,2054, have also been devised base electrode in an embodiment of the present invention, described base electrode (sign) is in tabular, and one end of described base electrode is connected with conductive plug, and the other end is connected with described hearth electrode.
Described hearth electrode is electrically connected with conductive plug 201 by base electrode, for heating phase change cells, the thickness of described hearth electrode is relevant with the contact area of described phase change cells, if the thickness of hearth electrode is too large, the more energy of usual needs consumption could heat the partial phase change unit contacted with hearth electrode, make the material of described partial phase change unit become amorphous state from crystalline state, for the consideration reducing power consumption, the thickness of described hearth electrode can not be too large; The material of described hearth electrode is electric conducting material, such as, one in metal material W, Pt, Au, Ti, Al, Ag, Cu, Ni, or by any two kinds of combinations in described metal material W, Pt, Au, Ti, Al, Ag, Cu, Ni or the alloy material of multiple combination.Along with the reduction of phase transition storage size, the structure of the corresponding phase change cells of a described diode, its electric current by diode reduces, driving force weakens, be difficult to the demand meeting memory function, the structure that diode is corresponding with multiple phase change cells then makes the space holding multiple diode in prior art may be used for the large diode of accommodation one, the cross-sectional area of described diode increases, according to the characteristic of diode, when external voltage is identical, increased by the electric current of described diode, driving force strengthens, to meet the demand of memory function.Because described hearth electrode is corresponding with phase change cells.Therefore, described hearth electrode is multiple, considers the demand better meeting memory function, and described hearth electrode is at least four.
In an embodiment of the present invention, the material of described hearth electrode is the one in Ti, TiN, Ta or TaN; The thickness of described hearth electrode is less than 100
described hearth electrode is four, and described four hearth electrodes 2031,2032,2033,2034 form square, and described hearth electrode 2031,2032,2033,2034 corresponds respectively to each square summit.
It should be noted that, in other embodiments of the invention, described hearth electrode 2031,2032,2033,2034 can be straight line, and the number of described hearth electrode also can be greater than four.
Described phase change cells and hearth electrode connect one to one, and the number of described phase change cells is corresponding with the number of hearth electrode, are at least four.The material of described phase change cells is phase-change material, such as GST.In a heated condition, there is reversible phase transformation in described phase-change material, described crystalline state and amorphous state are appointed as logical zero or " 1 " between crystalline state and amorphous state, realizes the function stored.
In an embodiment of the present invention, described phase change cells is four, is specially phase change cells 2051,2052,2053 and 2054.Wherein, described phase change cells 2051 is electrically connected with hearth electrode 2031, described phase change cells 2052 is electrically connected with hearth electrode 2032, described phase change cells 2053 is electrically connected with hearth electrode 2033, described phase change cells 2054 is electrically connected with hearth electrode 2034.
In other embodiments of the invention, the number of described phase change cells also can be greater than four, as long as can meet the demand of memory function.
Described top electrode is electrically connected with phase change cells one_to_one corresponding, for being connected with external signal; The material of described top electrode is electric conducting material, such as, one in metal material W, Pt, Au, Ti, Al, Ag, Cu, Ni, or by any two kinds of combinations in described metal material W, Pt, Au, Ti, Al, Ag, Cu, Ni or the alloy material of multiple combination; The number of described top electrode is corresponding with the number of hearth electrode, phase change cells.
In an embodiment of the present invention, described top electrode is four, is specially top electrode 2071,2072,2073,2074.Described top electrode 2071 is electrically connected with phase change cells 2051, described top electrode 2072 is electrically connected with phase change cells 2052, described top electrode 2073 is electrically connected with phase change cells 2053, described top electrode 2074 is electrically connected with phase change cells 2054.
It should be noted that, in an embodiment of the present invention, described phase-change memory cell also comprises: the wordline (not shown) be electrically connected with described diode 200 and the bit line (not shown) be electrically connected with described top electrode.Described wordline arranges along first direction, and for the memory cell of gating written information, described bit line arranges along the second direction vertical with described first direction, for memory cell reading and writing, wipe described information.
It should be noted that, the surface at described first direction, the second direction place vertical with described first direction is parallel with the surface that 2054 are formed with phase change cells 2051,2052,2053.
The partial structurtes schematic diagram of the phase transition storage of the embodiment of the present invention please refer to Fig. 3, illustrate only four diodes in Fig. 3, comprising the diode 200 shown in Fig. 2.
As shown in Figure 3, described diode 200, diode 210 are electrically connected with the first wordline 250, and described diode 220, diode 230 are electrically connected with the second wordline 260, and described first wordline 250 and the second wordline 260 arrange along first direction.For diode 200, corresponding top electrode 2071 is electrically connected with the first bit line 270, top electrode 2072 is electrically connected with the second bit line 275, top electrode 2073 is electrically connected with the 3rd bit line 280, described top electrode 2074 is electrically connected with the 4th bit line 285, and described first bit line 270, second bit line 275, the 3rd bit line 280, the 4th bit line 285 arrange along second direction.When external voltage is applied on the first wordline 250 and the first bit line 270, then can realizes read-write wiping to the region of top electrode 2071 correspondence and wait operation.
It should be noted that, in other embodiments of the invention, described wordline also can arrange along second direction, and described bit line arranges along first direction.
Accordingly, the inventor of the embodiment of the present invention additionally provides a kind of formation method of phase-change memory cell, please refer to Fig. 4, comprising:
Step S301, provides diode, forms the conductive plug that one end is connected with described diode electrically;
Step S303, forms the base electrode that is connected with described conductive plug of one end and the discrete hearth electrode of at least four of being connected with the other end of described base electrode;
Step S305, forms the phase change cells be electrically connected with described hearth electrode one_to_one corresponding;
Step S307, forms the top electrode connected one to one with described phase change cells.
For ease of understanding the formation method of the phase-change memory cell of the embodiment of the present invention, please refer to Fig. 4 ~ Figure 11, Fig. 5 ~ Figure 12 is the structural representation of the forming process of the formation method of the phase-change memory cell of the embodiment of the present invention.
Perform step S301, please refer to Fig. 5, diode (not shown) is provided, form the conductive plug 403 that one end is connected with described diode electrically.
For simplicity, not shown diode.The forming step of described conductive plug 403 is: form first medium layer 401 at Diode facets, the surface of described first medium layer 401 has third direction and the fourth direction vertical with described third direction; Form photoresist layer (not shown) on described first medium layer 401 surface, described photoresist layer has opening (not shown), and the position of described opening is corresponding with the position of the conductive plug 403 of follow-up formation; With described photoresist layer for first medium layer 401 described in mask etching, form the first groove (sign), described first groove exposes Diode facets; In described first groove, fill full electric conducting material, form conductive plug 403.
In an embodiment of the present invention, the material of described first medium layer 401 is oxide, such as silicon dioxide.The method that filled conductive material adopts in the first groove is depositing operation, such as physics or chemical vapour deposition (CVD).Afterwards, then adopt electric conducting material described in CMP (Chemical Mechanical Polishing) process planarization, form conductive plug 403, described conductive plug 403 flushes with first medium layer 401 surface.
It should be noted that, in an embodiment of the present invention, also need to remove photoresist layer.
Perform step S303, please refer to Fig. 6 ~ 8, form the base electrode (not shown) that is connected with described conductive plug of one end and the discrete hearth electrode (sign) of at least four of being connected with the other end of described base electrode.
Please refer to Fig. 6, form the second interlayer dielectric layer 405 being positioned at described first interlayer dielectric layer 401 surface, described second interlayer dielectric layer 405 has the first opening (sign), described first opening exposes conductive plug 403 and the first interlayer dielectric layer 401, and runs through the second interlayer dielectric layer 405 of third direction; Formed and cover the surface of described second interlayer dielectric layer 405 and the hearth electrode film 407 of sidewall and the first interlayer dielectric layer 401; Form the first stop-layer 409 covering described hearth electrode film 407.
The material of described second interlayer dielectric layer 405 is oxide, and described second interlayer dielectric layer 405 is for defining the position of the hearth electrode of follow-up formation.The formation method of described second interlayer dielectric layer 405 is depositing operation, such as physics or chemical vapour deposition (CVD).
Described hearth electrode film 407 is for follow-up formation base electrode and the hearth electrode that is connected with one end of described base electrode, and described hearth electrode film 407 covers the surface of described second interlayer dielectric layer 405 and the surface of sidewall and the first interlayer dielectric layer 401.In an embodiment of the present invention, the material of described hearth electrode film 407 is TiN, and the formation method of described hearth electrode film 407 is depositing operation, such as physics or chemical vapour deposition (CVD).
Described first stop-layer 409 is for as barrier layer during follow-up removal the second stop-layer 411.In an embodiment of the present invention, the material of described first stop-layer 409 is SiN.The formation method of described first stop-layer 409 is depositing operation, such as physics or chemical vapour deposition (CVD).
Please refer to Fig. 7, form the second stop-layer 411 being positioned at described first stop-layer 409 surface, described second stop-layer 411 has the second opening (sign), and described second opening exposes the first stop-layer 409, and runs through the second stop-layer 411 of fourth direction; Form dielectric layer 413 between third layer on described second stop-layer 411 surface, between described third layer, dielectric layer 413 exposes the second opening.
Between described second stop-layer 411 and third layer, the forming step of dielectric layer 413 is: adopt depositing operation to form the anti-reflection film covering described first stop-layer 409 surface; Depositing operation is adopted to form the oxide film covering anti-reflection film surface; Adopt photoetching, developing process removal part oxide film and partial anti-reflective film, form dielectric layer 413 between second stop-layer 411 with the second opening and the third layer being positioned at the second stop-layer 411 surface, described second opening exposes the first stop-layer 409, and run through the second stop-layer 411 of fourth direction, the position of described second stop-layer 411 defines the size of hearth electrode along third direction.
In an embodiment of the present invention, described second stop-layer 411 is bottom layer anti-reflection layer (BARC, Bottom Anti-Reflective Coating), for as barrier layer during follow-up removal part oxide film.
Please refer to Fig. 8, with dielectric layer between described third layer 413 and the second stop-layer 411 for mask, remove the second interlayer dielectric layer 405 of the first stop-layer 409, hearth electrode film 407 and segment thickness; Dielectric layer 413, second stop-layer 411, first stop-layer 409 and hearth electrode film between third layer described in planarization, after exposing the second interlayer dielectric layer 405, remove dielectric layer between described third layer, form base electrode and be positioned at the discrete storage area of at least four of base electrode surface, described four discrete storage areas are follow-up for the formation of four discrete hearth electrodes.
In an embodiment of the present invention, described four discrete storage areas are formed in same processing step, and need not be formed respectively, greatly save processing step, and formation process are simple.
Perform step S305, please refer to Fig. 9 ~ 11, form the phase change cells 4191,4192,4193 and 4194 be electrically connected with described hearth electrode one_to_one corresponding.
Please refer to Fig. 9, form the 4th interlayer dielectric layer 415 covering described first stop-layer 409 surface, the surface of described 4th interlayer dielectric layer 415 flushes with the second interlayer dielectric layer 405 surface.
Described 4th interlayer dielectric layer 415 is oxide, such as silicon dioxide.The formation method of described 4th interlayer dielectric layer 415 is high-density plasma deposition process, and described 4th interlayer dielectric layer 415 is for the follow-up support as top electrode.
Please refer to Figure 10, adopt photoetching, developing process removal part hearth electrode film 407, second interlayer dielectric layer 405 and the first stop-layer 409, form the second groove 417.
Described second groove 417, for follow-up filling phase-change material, forms phase change cells.The forming step of described second groove 417 is specially: form photoresist layer (not shown) on described 4th interlayer dielectric layer 415 surface, described photoresist layer has opening (not shown), the position of described opening is corresponding with the position of the phase change cells of follow-up formation, with described photoresist layer for mask removes hearth electrode film 407, second interlayer dielectric layer 405 and the first stop-layer 409, form the second groove 417.
The number of described second groove is corresponding with the number of phase change cells.In an embodiment of the present invention, described second groove 417 is four, and described second groove 417 exposes hearth electrode film 407.
Please refer to Figure 11, in described second groove, fill phase-change material form phase change cells.
The forming step of described phase change cells is: adopt depositing operation, such as physics or chemical vapour deposition (CVD) fill full phase variation film (sign) in described second groove, such as GST film; Phase-change thin film described in the method planarization of employing chemico-mechanical polishing, makes described phase-change thin film flush with the second interlayer dielectric layer 405 and the 4th interlayer dielectric layer 415 surface, forms phase change cells.
In an embodiment of the present invention, described phase change cells is four, is specially phase change cells 4191,4192,4193 and 4194.
It should be noted that, after step S305 is complete, described four discrete hearth electrodes are formed.
Perform step S307, please refer to Figure 12, form top electrode, described top electrode comprises the top electrode 4211,4212,4213,4214 be electrically connected with one_to_one corresponding of the described end 4191,4192,4193 and 4194 respectively.
The forming step of described second electrode is: form the top electrode film (sign) covering described phase change cells, the second interlayer dielectric layer 405 and the 4th interlayer dielectric layer 415; Form photoresist layer (not shown) at described top electrode film surface, described photoresist layer is corresponding with the position of top electrode 4211,4212,4213,4214; With described photoresist layer for mask removes top electrode film, form top electrode 4211,4212,4213,4214.
It should be noted that, in an embodiment of the present invention, the formation method of described phase-change memory cell also comprises: with described photoresist layer for mask removes the first interlayer dielectric layer 401, second interlayer dielectric layer 405, first stop-layer 409 and the 4th interlayer dielectric layer 415, forms the phase-change memory cell of the embodiment of the present invention as shown in Figure 2.
It should be noted that, in an embodiment of the present invention, for making described phase-change memory cell realize memory function, the formation method of described phase-change memory cell also comprises: form the bit line (details please refer to Fig. 3) connected one to one with described top electrode 4211,4212,4213,4214.
After above-mentioned steps completes, completing of the phase-change memory cell of the embodiment of the present invention.
To sum up, the phase-change memory cell of the embodiment of the present invention comprises: diode and at least four phase change cells be connected with described diode electrically.Prior art is for holding the region of at least four diodes in embodiments of the present invention only for holding a diode, therefore the size of the diode of the embodiment of the present invention is greater than the size of diode in prior art, under the condition that the voltage provided at peripheral circuit is identical, the electric current of diode in prior art is greater than through the electric current of the diode of the embodiment of the present invention, the driving force of the diode of the embodiment of the present invention is strengthened, thus meets the demand of the memory function of phase transition storage.
Although the present invention with preferred embodiment openly as above; but it is not for limiting the present invention; any those skilled in the art without departing from the spirit and scope of the present invention; the Method and Technology content of above-mentioned announcement can be utilized to make possible variation and amendment to technical solution of the present invention; therefore; every content not departing from technical solution of the present invention; the any simple modification done above embodiment according to technical spirit of the present invention, equivalent variations and modification, all belong to the protection range of technical solution of the present invention.
Claims (5)
1. a formation method for phase-change memory cell, comprising:
Diode is provided;
It is characterized in that, also comprise:
Form be connected with described diode electrically at least four discrete hearth electrodes, when described diode electrically connects four discrete hearth electrodes, these four hearth electrodes lay respectively at each square summit;
Form the phase change cells be electrically connected with described hearth electrode one_to_one corresponding;
Form the conductive plug that one end is connected with described diode; The forming step of described conductive plug is: form first medium layer at Diode facets, the surface of described first medium layer has third direction and the fourth direction vertical with described third direction; Form photoresist layer on described first medium layer surface, described photoresist layer has opening, and the position of described opening is corresponding with the position of the conductive plug of follow-up formation; With described photoresist layer for first medium layer described in mask etching, form the first groove, described first groove exposes Diode facets; In described first groove, fill full electric conducting material, form conductive plug;
Form base electrode, one end of described base electrode is connected with conductive plug, and the other end is connected with described hearth electrode; Form the top electrode connected one to one with described phase change cells; Form the bit line connected one to one with described top electrode.
2. the formation method of phase-change memory cell as claimed in claim 1, it is characterized in that, the forming step of described hearth electrode comprises: form the second interlayer dielectric layer being positioned at dielectric layer surface between ground floor, described second interlayer dielectric layer has the first opening, described first opening exposes conductive plug and the first interlayer dielectric layer, and runs through the second interlayer dielectric layer of third direction; Formed and cover the surface of described second interlayer dielectric layer and the hearth electrode film of sidewall and the first interlayer dielectric layer; Form the first stop-layer covering described hearth electrode film; Form the second stop-layer being positioned at described first stop-layer surface, described second stop-layer has the second opening, and described second opening exposes the first stop-layer, and runs through the second stop-layer of fourth direction; Formed be positioned at described second stop-layer surface third layer between dielectric layer, between described third layer, dielectric layer exposes the second opening; With dielectric layer between described third layer and the second stop-layer for mask, remove the second interlayer dielectric layer of the first stop-layer, hearth electrode film and segment thickness; Dielectric layer, the second stop-layer, the first stop-layer and hearth electrode film between third layer described in planarization, after exposing the second interlayer dielectric layer, remove dielectric layer between described third layer, forms base electrode and at least four discrete storage areas.
3. the formation method of phase-change memory cell as claimed in claim 2, it is characterized in that, the forming step of described phase change cells is: form the 4th interlayer dielectric layer covering described first stop-layer surface, the surface of described 4th interlayer dielectric layer flushes with dielectric layer surface between the second layer; Photoresist layer is formed on described 4th interlayer dielectric layer surface, described photoresist layer has opening, the position of described opening is corresponding with the position of the phase change cells of follow-up formation, with described photoresist layer for mask removes hearth electrode film, the second interlayer dielectric layer and the first stop-layer, form the second groove; Full phase-change material is filled in described second groove.
4. the formation method of phase-change memory cell as claimed in claim 3, it is characterized in that, the forming step of described top electrode is: form the top electrode film covering described phase change cells, the second interlayer dielectric layer and the 4th interlayer dielectric layer; Form photoresist layer at described top electrode film surface, the position of described photoresist layer is corresponding with the position of top electrode; With described photoresist layer for mask removes top electrode film, form top electrode.
5. the formation method of phase-change memory cell as claimed in claim 4, is characterized in that, also comprise: with described photoresist layer for mask removes the first interlayer dielectric layer, the second interlayer dielectric layer, the first stop-layer and the 4th interlayer dielectric layer.
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| CN201110136665.1A CN102800805B (en) | 2011-05-25 | 2011-05-25 | Phase change storage unit and forming method thereof |
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| CN102800805B true CN102800805B (en) | 2014-12-24 |
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| CN101911298A (en) * | 2008-01-16 | 2010-12-08 | 美光科技公司 | 3-d and 3-d schottky diode for cross-point, variable-resistance material memories, processes of forming same, and methods of using same |
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| KR100971423B1 (en) * | 2008-04-04 | 2010-07-21 | 주식회사 하이닉스반도체 | Phase change memory device and method for manufacturing the same |
| JP5329987B2 (en) * | 2009-01-09 | 2013-10-30 | 株式会社東芝 | Semiconductor memory device and manufacturing method thereof |
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| CN101911298A (en) * | 2008-01-16 | 2010-12-08 | 美光科技公司 | 3-d and 3-d schottky diode for cross-point, variable-resistance material memories, processes of forming same, and methods of using same |
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