CN102664168A - Nonvolatile memory device and method of fabricating same - Google Patents
Nonvolatile memory device and method of fabricating same Download PDFInfo
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Abstract
A nonvolatile memory device and a method of fabricating the same are provided to prevent charges stored in a charge trap layer from moving to neighboring memory cells. The method of fabricating a nonvolatile memory device, includes forming a first dielectric layer on a semiconductor substrate in which active regions are defined by isolation layers, forming a charge trap layer on the first dielectric layer, removing the first dielectric layer and the charge trap layer over the isolation layers, forming a second dielectric layer on the isolation layers including the charge trap layer, and forming a conductive layer on the second dielectric layer.
Description
The application is that application number is 200810142856.7, the applying date is on March 24th, 2008, the application people is Hynix Semiconductor Inc, denomination of invention dividing an application for the application for a patent for invention of " Nonvolatile memory devices and manufacturing approach thereof ".
Technical field
The present invention relates to a kind of Nonvolatile memory devices and manufacturing approach thereof.
Background technology
Generally speaking, the memory cell of the Nonvolatile memory devices of storing therein data has stacked gate architectures.This stacked gate architectures be through sequentially pile up dielectric layer between tunnel dielectric layer, floating grid, grid on the channel region of memory cell, control grid and gate electrode form.This floating grid is as electric charge capture layer, and formed by the conductive layer of for example polysilicon usually.
Yet, disclosed use non-conductive layer (for example, nitride layer) and replaced the Nonvolatile memory devices of polysilicon as electric charge capture layer.According to the material of gate electrode layer etc., aforesaid use non-conductive layer can be categorized into SONOS (silicon/oxide/nitride/oxide/silicon) Nonvolatile memory devices, MANOS (metal/Al as the Nonvolatile memory devices of electric charge capture layer
2O
3/ nitride/oxide/silicon) Nonvolatile memory devices etc.This Nonvolatile memory devices has tunnel dielectric layer, the nitride layer that is used for stored charge that forms the direct Tunneling layer, insulating barrier and the control grid electrode that is used as the barrier layer.
In using the Nonvolatile memory devices of conductive layer as electric charge capture layer of polysilicon for example, there is such problem, if there is any microdefect in the floating grid, then the retention time (retention time) significantly reduces.Yet, in using the Nonvolatile memory devices of non-conductive layer as electric charge capture layer of nitride layer for example, have such advantage, because the characteristic of nitride layer is relatively little to the sensitiveness of the defective in the technology.
In addition, in using the Nonvolatile memory devices of conductive layer as electric charge capture layer, because the above tunnel dielectric layer of about 70 dusts of thickness is formed under the floating grid, there is limitation in the enforcement of low voltage operating and high speed operation.Yet, in using the Nonvolatile memory devices of non-conductive layer, have high speed operation and require low-voltage and the storage device of low-power consumption can be realized, because the direct Tunneling dielectric layer of relative thin is formed under the nitride layer as electric charge capture layer.
When make using non-conductive layer as the Nonvolatile memory devices of electric charge capture layer; Generally speaking; Separator is formed in the Semiconductor substrate through STI (shallow trench isolation leaves) scheme; And gate oxide level, the nitride layer that is used for stored charge, the oxide skin(coating) that is used as the barrier layer, gate electrode layer etc. are formed on the Semiconductor substrate that comprises separator.Carry out the gate pattern metallization processes then, thereby form the grid that constitutes memory cell.
Yet; Use the flash memory device of non-conductive layer if make as electric charge capture layer; The nitride layer that is used for stored charge is not formed at each memory cell discretely, but interconnects along the direction of memory cell, even after the gate pattern metallization processes is carried out.The electric charge of catching in the electric charge capture layer that comprises in the particular memory location in the case, can be diffused in the contiguous memory cell by along continuous straight runs along with time lapse.
Fig. 1 is a profile, and the conventional method of making MANOS type Nonvolatile memory devices is described.
See Fig. 1, thereby Semiconductor substrate 10 is etched the formation groove.Fill (gap-filling) groove with the insulating barrier slit, form separator 11.Tunnel dielectric layer 12 is formed on the active area of semiconductor device then.Electric charge capture layer 13, barrier insulating layer 14, metal electrode layer 15 and gate electrode layer 16 and 17 sequentially are formed on the whole surface.Thereby carry out the grid that the gate pattern etch process forms the unit area then.
In traditional M ANOS type Nonvolatile memory devices, electric charge capture layer 13 also is formed on the isolated area between the active area.Therefore, if through with electric charge capture to electric charge capture layer 13 implement the programming after, toast at high temperature, the electric charge of then catching moves to contiguous grid, this can reduce programmed threshold voltage.This causes the retention performance (that is the electric charge hold facility of unit) of degenerating.
Fig. 2 is a profile, and the conventional method of making SONOS type Nonvolatile memory devices is described.
See Fig. 2, thereby the isolated area of Semiconductor substrate 20 is etched the formation isolated groove.Use insulating barrier slit filling groove, form separator 21.Tunnel dielectric layer 22, electric charge capture layer 23, barrier layer 24, the conductive layer 25 and the gate electrode layer 26 that are used to control grid sequentially are stacked in the whole surface that comprises separator 21.
In traditional SONOS type Nonvolatile memory devices, low-voltag transistor and high voltage transistor at first are formed at outer peripheral areas (that is, the neighboring area), will form as the unit of storage medium (medium) then.According to said method, the electric charge capture layer of unit area is shared along word-line direction and adjacent unit.Occur such problem thus,, thereby reduce the programmed threshold voltage of unit because the electric charge of catching can move to adjacent gate.This causes the retention performance (that is the electric charge hold facility of unit) of degenerating.
In addition, with floating grid relatively, the charge-trapping efficient of electric charge capture layer is about 70% because not all electric charge through tunnel dielectric layer all is hunted down, but only wherein part be hunted down.Like this, must compensate and the corresponding threshold voltage of this low efficient through increasing program bias, but be difficult to be formed for transmitting high-tension high voltage transistor.
Summary of the invention
Thereby the object of the invention is only in each memory cell, to form electric charge capture layer through electric charge capture layer is carried out Patternized technique, prevents that thus charge stored is diffused into contiguous memory cell in the electric charge capture layer.
In addition; The present invention also aims to provide a kind of method of making non-volatile memory device; Through forming electric charge capture layer in the space between the separator that in the isolated area of Semiconductor substrate, forms; Thereby prevent that when programming operation the electric charge of catching in the electric charge capture layer is diffused in the grid of adjacent unit, improves the retention performance of programmed threshold voltage and unit thus.
Further; The present invention also aims to provide a kind of method of making non-volatile memory device; It is through forming electric charge capture layer on Semiconductor substrate; Form separator through subsequent technique subsequently; Thereby with the charge storing unit capture layer and along other contiguous charge storing unit capture layer electric isolation of bit line direction, can prevent that thus the electric charge of catching in the electric charge capture layer from moving in the adjacent unit grid when programming operation, and improve the retention performance of programmed threshold voltage and unit thus through this separator.
According to an aspect of the present invention, kind of a method of making non-volatile memory device is provided, comprises: on Semiconductor substrate, form first dielectric layer, in Semiconductor substrate, define active area by separator; On first dielectric layer, form electric charge capture layer; Remove first dielectric layer and electric charge capture layer on the separator; Comprising formation second dielectric layer on the separator of electric charge capture layer; And on second dielectric layer, form conductive layer.
Electric charge capture layer can be formed on the active area and the marginal portion of separator.
Electric charge capture layer can only be formed on the active area.In Semiconductor substrate, forming separator comprises: on Semiconductor substrate, form pad nitride layer; On pad nitride layer, form first mask pattern, this first mask pattern has and the corresponding open area of separator; Use first mask pattern to come the patterning pad nitride layer and in Semiconductor substrate, form groove; And with the filling insulating material groove to form separator.First mask pattern can have the same or wideer open area with second mask pattern.
Electric charge capture layer can by insulating material for example nitride layer form.
According to another aspect of the present invention, a kind of Nonvolatile memory devices is provided, it comprises: Semiconductor substrate defines active area by separator in the Semiconductor substrate; First dielectric layer is isolated each other and is formed in the active area respectively; Electric charge capture layer forms and only is formed on first dielectric layer by insulating material; Second dielectric layer is formed on Semiconductor substrate and the electric charge capture layer; And conductive layer, be formed on second dielectric layer.
First dielectric layer can partly be formed on the separator.
According to another aspect of the present invention, a kind of method of making non-volatile memory device is provided, comprises: order forms insulating barrier and hard mask layer on Semiconductor substrate; Isolated area through the etch process that uses hard mask layer comes the etching semiconductor substrate forms groove; Use insulating barrier slit filling groove, form separator thus; In the zone that comprises separator, be used for forming passivation dielectric layer on the hard mask of insulating barrier; Etching and remove passivation dielectric layer, hard mask layer and insulating barrier, thus outstanding separator formed; Sequentially pile up tunnel dielectric layer, electric charge capture layer and buffering dielectric layer on the whole surface of the base semiconductor that comprises separator; And carry out glossing to expose the end face of outstanding separator, make tunnel dielectric layer and electric charge capture layer be retained on the active area of base semiconductor.
After the glossing, can sequentially pile up barrier insulating layer, metal level and gate electrode layer on the whole surface that comprises separator.
Passivation dielectric layer can be that the nitride layer of 200 to 4000 dusts forms through LP-CVD (low-pressure chemical vapor deposition) or PE-CVD (plasma enhanced chemical vapor deposition) method by thickness.The outstanding height of separator can be in the scope of 200 to 800 dusts.
Tunnel dielectric layer can be passed through dry method thermal oxidation technology, means of wet thermal oxidation technology or free-radical oxidation technology and form.The height of electric charge capture layer can be lower than the height of separator end face.
Electric charge capture layer can be formed through LP-CVD or PE-CVD method by silicon nitride or the persilicic nitride of thickness in the stoichiometric proportion of 40 to 200 dusts.
The buffer medium layer can be formed at the HDP of 500 to 4000 dusts (high-density plasma), SOG (spin-coating glass), USG (undoped silicate glass), PSG (phosphosilicate glass) or BPSG (boron phosphorus silicate glass) by thickness.
According to another aspect of the present invention; A kind of method of making non-volatile memory device is provided; Comprise a kind of method of making non-volatile memory device; Comprise and sequentially pile up first tunnel dielectric layer, electric charge capture layer, barrier insulating layer and first conductive layer on Semiconductor substrate that definition has unit area and outer peripheral areas in the Semiconductor substrate; Form isolated groove through etching first conductive layer, barrier insulating layer, electric charge capture layer, first tunnel dielectric layer and Semiconductor substrate; Form separator through using the insulating barrier slit to fill isolated groove; And sequentially form second conductive layer and metal gate layers on the whole surface that comprises first conductive layer.
This method also comprises: after forming separator, form before the formation of second conductive layer, in the unit area, form passivation dielectric layer; Remove first conductive layer, barrier insulating layer, electric charge capture layer and first tunnel dielectric layer that are formed in the outer peripheral areas; Be formed at the outstanding end face of the separator of outer peripheral areas through etching, the height of control separator; On the Semiconductor substrate of exposing of outer peripheral areas, be formed for transistorized second tunnel dielectric layer; And remove passivation dielectric layer.
Tunnel dielectric layer can be formed by the oxide skin(coating) of thickness at the 10-100 dust.Electric charge capture layer can be formed by oxide skin(coating) and mixed layer or the nitride layer of nitride layer of thickness 10 to 100 dusts.Barrier insulating layer can have the dual structure of oxide skin(coating), nitride layer or oxide skin(coating) and nitride layer, and forms thickness at 10 to 500 dusts.First and second conductive layers that are used to control grid can be formed by polysilicon layer.
After forming first conductive layer, can before forming, carry out ion implantation technology, with the further iunjected charge capture layer of ion at isolated groove.Ion implantation technology can use As or P as impurity.
Passivation dielectric layer can be formed by nitride layer.
For the situation of high voltage transistor, be used for transistorized tunnel dielectric layer and can form thickness between 100 to 600 dusts, for the situation of low-voltag transistor, be used for transistorized tunnel dielectric layer and can form thickness between 100 to 200 dusts.
Electric charge capture layer can be formed by the mixed layer or the nitride layer of oxide skin(coating) and nitride layer.Electric charge capture layer can be by HfO
2, ZrO
2, HfAlO, HfSiO, ZrAlO or ZrSiO form.After forming barrier insulating layer, can carry out RTP (rapid thermal treatment) to improve the film quality of barrier insulating layer.
First conductive layer and second conductive layer can be formed by polysilicon layer or metal level.Polysilicon layer can be by doping N
+The polysilicon layer of impurity forms.Ion doping concentration can be at 1E19 atom/cm
3To 5E20 atom/cm
3Between.Metal level can be formed by TaN.
According to another aspect of the present invention, a kind of non-volatile memory device is provided, comprises: tunnel dielectric layer, electric charge capture layer, barrier insulating layer and first conductive layer sequentially are stacked on the Semiconductor substrate; Separator; This separator is the same highly with the height of first conductive layer in the isolated area of Semiconductor substrate outstanding, and is configured to tunnel dielectric layer, electric charge capture layer, barrier insulating layer and first conductive layer and contiguous tunnel dielectric layer, contiguous electric charge capture layer, contiguous barrier insulating layer and the first contiguous conductive layer are isolated; And second conductive layer and metal gate layers, sequentially be stacked on the separator and first conductive layer.
Electric charge capture layer can be formed by the mixed layer or the nitride layer of oxide skin(coating) and nitride layer.Electric charge capture layer can be by HfO
2, ZrO
2, HfAlO, HfSiO, ZrAlO or ZrSiO form.
Description of drawings
Fig. 1 makes the profile of the conventional method of MANOS type Nonvolatile memory devices for explanation;
Fig. 2 makes the profile of the conventional method of SONOS type Nonvolatile memory devices for explanation;
Fig. 3 A is the profile of explanation according to the method for the manufacturing Nonvolatile memory devices of the first embodiment of the present invention to 3F;
Fig. 4 A is to the profile of 4G for the method for explanation manufacturing Nonvolatile memory devices according to a second embodiment of the present invention;
Fig. 5 A is to the profile of 5E for the method for the manufacturing Nonvolatile memory devices of explanation a third embodiment in accordance with the invention.
Embodiment
Now, will illustrate and describe according to a particular embodiment of the invention.Yet the present invention is not limited to the embodiment that disclosed, but can implement in many ways.Embodiment is provided accomplishing announcement of the present invention, and makes those of ordinary skill in the art can understand scope of the present invention.Category of the present invention is defined by the claims.
Fig. 3 A is the profile of explanation according to the method for the manufacturing Nonvolatile memory devices of the first embodiment of the present invention to 3F.
See Fig. 3 A, form the screen oxide layer (not shown) on Semiconductor substrate 300.The screen oxide layer function be prevent subsequent technique for example in trap ion implantation technology or the threshold voltage ion implantation technology to the damage on Semiconductor substrate 300 surfaces.Subsequently, carry out the trap ion implantation technology, carry out the threshold voltage ion implantation technology with the for example transistorized threshold voltage of control semiconductor element in Semiconductor substrate 300, to form well region.The well region (not shown) is formed in the Semiconductor substrate 300, and can have triple (triple) structure.
After removing screen oxide layer, form liner (pad) nitride layer 302 on semiconductor layer 300.Then, form first mask pattern 304 on pad nitride layer 302.First mask pattern 304 has and in subsequent technique, is formed at the corresponding open area of groove (open region) in the Semiconductor substrate 300.Oxide skin(coating) (not shown) with the etching selectivity that is different from pad nitride layer 302 can further be formed between the pad nitride layer 302 and first mask pattern 304.This oxide skin(coating) (not shown) can be used for preventing in subsequent etch technology the damage to Semiconductor substrate 300 surfaces.
See Fig. 3 B, pad nitride layer 302 (seeing Fig. 3 A) is patterned as the etch process of etching mask through using first mask pattern 304 (seeing Fig. 3 A).Groove is formed in the Semiconductor substrate 300 subsequently.Insulating material is formed on first mask pattern 304 that comprises groove (seeing Fig. 3 A), thereby uses insulating material slit filling groove.Be formed at insulating material, first mask pattern 304 (seeing Fig. 3 A) and pad nitride layer 302 (seeing Fig. 3 A) on the Semiconductor substrate 300 through Semiconductor substrate 300 is carried out glossings, for example CMP (chemico-mechanical polishing) technology and removing.Therefore, insulating material only is retained in the groove that is formed in the Semiconductor substrate 300, forms separator 306 thus.A plurality of active area (not shown) are also by 306 definition of the isolated area in the Semiconductor substrate 300.
See Fig. 3 C, first dielectric layer 308 is formed on the Semiconductor substrate 300 that comprises isolated area 306.First dielectric layer 308 can be used as tunnel dielectric layer in using the Nonvolatile semiconductor memory device of non-conductive layer as electric charge capture layer.Electric charge capture layer 310 is formed on first dielectric layer 308 subsequently.Electric charge capture layer 310 is formed at the entire upper surface top of Semiconductor substrate 300, is positioned at a plurality of active areas top by separator 306 definition.Electric charge capture layer 310 can be non-conductive layer, for example nitride layer.
See Fig. 3 D, the resilient coating 312, electric charge capture layer 310 and first dielectric layer 308 that are formed under second mask pattern 314 come patterning through using second mask pattern 314 as the etch process of etching mask.Therefore, the electric charge capture layer 310 that is arranged in the open area of second mask pattern 314 is removed.Electric charge capture layer 310 forms and flatly is connected in a plurality of active areas top, on active area, does not connect and isolates.Here, the marginal portion of electric charge capture layer 310 is adjusted to the boundary member of separator 306.Yet; If the open area of second mask pattern 314 is much smaller than the open area of first mask pattern 304; The width of the electric charge capture layer 310 that after the etch process that uses second mask pattern 314, keeps is by further broadening, thereby the electric charge capture layer 310 that part does not connect can be present on the separator 306.In this case, the quantity that is stored in the electric charge in the electric charge capture layer 310 can increase, thereby improves the characteristic of device.Simultaneously, if the open area of second mask pattern 314 is the same with the open area of first mask pattern 304 big, electric charge capture layer 310 is not present on the separator 306, and can only be formed on the active area.
Traditionally, electric charge capture layer 310 flatly is formed at a plurality of active areas top, even and still along continuous straight runs maintenance connection above a plurality of memory cell after follow-up gate etch process.In this case, charge stored can flatly spread along with time lapse in the electric charge capture layer 310 that comprises in the particular storage, therefore caused the skew of threshold voltage owing to potential energy difference.The data retention characteristics of this memory cell of can degenerating.Along with the size of memory cell diminishes gradually, must consider this problem gravely.
As above, according to the present invention, electric charge capture layer 310 is isolated each other, so that they only are formed in the active area respectively.Therefore, electric charge capture layer 310 can be isolated each other, and only is formed in the respective memory unit that forms through subsequent technique.Correspondingly, this can reduce the generation of the problem of degenerating such as potential energy decline, threshold voltage shift and data retention characteristics that when charge stored moves to contiguous memory cell in the electric charge capture layer 310, produces.
See Fig. 3 E, second mask pattern 314 (seeing Fig. 3 D) and the resilient coating 312 (seeing Fig. 3 D) that are formed on the Semiconductor substrate 300 are removed.
See Fig. 3 F, second dielectric layer 316 is formed at Semiconductor substrate 300 tops that comprise separator 306 and electric charge capture layer 310.Second dielectric layer 316 can form, and keeps the step that is formed by first dielectric layer 308 that is stacked in Semiconductor substrate 300 tops and electric charge capture layer 310 simultaneously.Second dielectric layer 316 can be by oxide skin(coating) Al for example
2O
3Form.At this moment, charge stored can't move to contiguous electric charge capture layer 310 in the electric charge capture layer 310, because between the electric charge capture layer 310 and second dielectric layer 316, have energy barrier.Conductive layer 318 is formed on second dielectric layer 316 subsequently.Conductive layer 318 can be formed by metal level.Though not shown, comprise the formation technology of memory cell of the electric charge capture layer 310 of mutual isolation, be through gate etch process stack layer to be carried out patterning to accomplish.
Fig. 4 A is to the profile of 4G for the method for explanation manufacturing Nonvolatile memory devices according to a second embodiment of the present invention.
See Fig. 4 A, cover (capping) dielectric layer 401, the insulating barrier 402 that is used to form separator and hard mask layer 403 and sequentially be formed at Semiconductor substrate 400 tops.Blanket dielectric layer 401 can be formed by oxide skin(coating).The gross thickness of blanket dielectric layer 401, insulating barrier 402 and hard mask layer 403 can be between 500 to 4000 dusts.Insulating barrier 402 can be formed by nitride layer.Subsequently, the photoresist pattern 404 that is used to form isolated groove is through exposure and developing process formation.
See Fig. 4 B, hard mask layer 403, insulating barrier 402 and blanket dielectric layer 401 are through with photoresist pattern 404 being etch process and the etching sequentially and the patterning of etching mask.The Semiconductor substrate 400 of exposure is etched to form groove 405.Groove 405 can form through etching semiconductor substrate 400, and the degree of depth of groove 405 is between 1500 to 2500 dusts.
See Fig. 4 C, through after peeling off (strip) technology and removing the photoresist pattern, insulating layer deposition is on whole surface.Carry out CMP technology then to expose hard mask layer 403, in groove 405, form separator 406 thus.Separator 406 can be formed by HDP (high-density plasma) oxide skin(coating), SOG (spin-coating glass) oxide skin(coating), USG (undoped silicate glass), PSG (phosphosilicate glass) or BPSG (boron phosphorus silicate glass).Passivation dielectric layer 407 is formed on the whole surface that comprises separator 406 subsequently.Passivation dielectric layer 407 plays a part to prevent end face loss in subsequent etch technology of separator 406.Passivation dielectric layer 407 can be by using LP-CVD or PE-CVD method to be formed by nitride layer, and its thickness is at 200 to 4000 dusts.
See Fig. 4 D, through carrying out etch process, sequentially remove being formed at passivation dielectric layer 407, hard mask layer 403, insulating barrier 402 and the blanket dielectric layer 401 of active area top.Separator 406 has the protuberance (protrusion) that projects upwards from Semiconductor substrate 400.The height of protuberance can be between the scope of 200 to 800 dusts.Here, passivation dielectric layer 407, hard mask layer 403 and insulating barrier 402 can be through using H
2PO
4Wet etching process remove.Alternatively, passivation dielectric layer 407, hard mask layer 403 and insulating barrier 402 can be removed through dry method etch technology.
See Fig. 4 E, tunnel dielectric layer 408 is formed on the active area of Semiconductor substrate 400.That is to say that tunnel dielectric layer 408 is formed in the zone between the separator 406.Tunnel dielectric layer 408 can be passed through dry method thermal oxidation technology, means of wet thermal oxidation technology or free-radical oxidation technology and form.Electric charge capture layer 409 is formed on the whole surface that comprises tunnel dielectric layer 408 subsequently.Here, the thickness that is formed on the electric charge capture layer 409 on the active area can be lower than the thickness of the electric charge capture layer 409 on the end face that is formed on separator 406.Electric charge capture layer 409 can use LP-CVD or PE-CVD method to form, and its thickness is at 40 to 200 dusts.Electric charge capture layer 409 can be formed by the silicon nitride or the persilicic nitride of stoichiometric proportion.Buffer medium layer 410 is formed at whole surface subsequently.Buffer medium layer 410 can be formed by HDP oxide, SOG, USG, PSG or BPSG, and its thickness is at 500 to 4000 dusts.
See Fig. 4 F, carry out the CMP processing and expose up to the end face of separator 406.So, the electric charge capture layer 409 that is formed on the end face of separator 406 is removed, and makes electric charge capture layer 409 only be retained on the active area.
See Fig. 4 G, barrier insulating layer 411, metal level 412, first grid electrode layer 413 and second gate electrode layer 414 sequentially are stacked on the whole surface that comprises separator 406.Thereby carry out the grid that Patternized technique forms the unit area then.Barrier insulating layer 411 can be by SiO
2(silica), Al
2O
3(aluminium oxide) (that is high dielectric constant material), Ta
2O
5(tantalum oxide), ZrO
3(zirconia), HfO
2(hafnium oxide), La
2O
3(lanthana), TiO
2(titanium oxide), SrTiO
3The oxide and the ferroelectric material of (strontium oxide strontia titanium oxide) or its combination or calcium titanium structure form.Metal level 412 can be formed by TiN, TiCN, TaN or TaCN.Each of barrier insulating layer 411 and metal level 412 can be formed by CVD (chemical vapour deposition (CVD)), PVD (physical vapour deposition (PVD)) or ALD (ald) method.First grid electrode layer 413 can be formed by polysilicon, and second gate electrode layer can be formed by WSix.
Fig. 5 A is to the profile of 5E for the method for the manufacturing Nonvolatile memory devices of explanation a third embodiment in accordance with the invention.
See Fig. 5 A, first tunnel dielectric layer 501 sequentially is formed on the Semiconductor substrate 500 with electric charge capture layer 502.First tunnel dielectric layer 501 can use free-radical oxidation method or thermal oxidation process to be formed by oxide skin(coating), is 10 to 500 dusts by thickness.Electric charge capture layer 502 can be formed by nitride layer.Electric charge capture layer 502 can use ALD or CVD method to form.Electric charge capture layer 502 can be that the LP-CVD nitride layer or the PE-CVD nitride layer of 10 to 500 dusts forms by thickness.Electric charge capture layer 502 can be replaced nitride layer to form by the mixed layer of oxide skin(coating) and nitride layer.Electric charge capture layer 502 also can be by HfO
2, ZrO
2, HfAIO, HfSiO, ZrAlO or ZrSiO form.
The barrier insulating layer 503 and first conductive layer 504 sequentially pile up subsequently.Barrier insulating layer 503 can be formed by oxide skin(coating).Barrier insulating layer 503 also can be by hafnium oxide, and aluminum oxide or Zirconium oxide form.Alternatively, barrier insulating layer 503 can be by nitride layer but not oxide skin(coating) form.Alternatively, barrier insulating layer 503 can have the dual structure of oxide skin(coating) and nitride layer.Barrier insulating layer 503 forms the thickness of 10 to 500 dusts.After barrier insulating layer 503 forms, can carry out RTP (rapid thermal treatment) to improve the film quality of barrier insulating layer 503.
First conductive layer 504 can be formed by polysilicon layer or metal level.Polysilicon layer can be by doping N
+The polysilicon layer of impurity forms.In this case, the ion doping concentration of polysilicon layer can be at 1E19 atom/cm
3To 5E20 atom/cm
3Scope.The TaN layer can be used as this metal level to form first conductive layer 504.
After this, carry out ion implantation technology, to increase the possible trap number of electric charge capture layer 502.As can be injected or P carries out this ion implantation technology as impurity.On first conductive layer 504, form hard mask layer 505 subsequently.
See Fig. 5 B; The isolated area that is formed at the unit area through etching sequentially (promptly; Memory cell region) hard mask layer 505 on, first conductive layer 504, barrier insulating layer 503, electric charge capture layer 502 and first tunnel oxide 501 are to expose Semiconductor substrate 500.Thereby the Semiconductor substrate of exposing 500 is etched and in the unit area, forms groove 506a.Through similar methods, in the isolated area of outer peripheral areas (that is neighboring area), form groove 506b.The groove 506a of unit area and the groove 506b of outer peripheral areas can form respectively or form simultaneously.
Comprising the insulating barrier 507 that is formed for element separation on the whole surface of groove 506a, 506b.Insulating barrier 507 can be formed by SOG, SOD or HDP oxide skin(coating).
Can be after barrier insulating layer 503 forms with 504 formation of first conductive layer before, carry out formation technology and the formation technology of insulating barrier 507 of groove 506b of groove 506a and the outer peripheral areas of unit area.
See Fig. 5 C, carry out glossing and expose up to first conductive layer 504.Preferably, thus can carry out CMP technology forms separator 507.For the formation technology of the groove 506b of groove 506a that after barrier insulating layer 503 forms, carries out the unit area and outer peripheral areas and the formation technology of insulating barrier 507; And do not form the situation of first conductive layer 504, preferably carry out glossing and expose up to barrier insulating layer 503.
Therefore, through separator 507, electric charge capture layer 502 is along bit line direction and contiguous electric charge capture layer 502 electric insulations.This prevents that the electric charge of being caught from moving to contiguous unit.
See Fig. 5 D,, expose Semiconductor substrate 500 thus through sequentially being etched in first conductive layer 504, barrier insulating layer 503, electric charge capture layer 502 and first tunnel oxide of exposing on the outer peripheral areas 501.Here, first tunnel oxide 501 can not be removed and keeps, thereby forms it into second tunnel dielectric layer through its thickness of control in follow-up oxidation technology.Thereafter, thus the height of the outstanding end face control separator 507 of etch isolates layer 507.Thereby carry out oxidation technology then and on the Semiconductor substrate of exposing 500, form second tunnel dielectric layer 509.Second tunnel dielectric layer 509 can be formed by oxide skin(coating).When transistor to be formed in the outer peripheral areas is low-voltag transistor; Second tunnel dielectric layer 509 can form thickness at 500 to 200 dusts; And when transistor to be formed in the outer peripheral areas was high voltage transistor, second tunnel dielectric layer 509 can form thickness at 500 to 600 dusts.
As stated, in the unit area, form after the passivation dielectric layer 508, can be formed for high-tension tunnel dielectric layer in outer peripheral areas.Correspondingly, can easily form high voltage transistor.
Carry out etch process subsequently to remove the passivation dielectric layer 508 that is formed in the memory cell region.
See Fig. 5 E, second conductive layer 510 is formed on the whole surface that is included in first conductive layer 504 that forms in the unit area and second tunnel dielectric layer 509 that in outer peripheral areas, forms.Second conductive layer 510 can be by forming with first conductive layer, 504 identical materials.In order to reduce the resistivity of gate electrode, on second conductive layer 510, form metal gate layers 511.If first conductive layer 504 and second conductive layer 510 are to be formed by polysilicon layer, metal gate layers 511 can be formed by WSi or WN/WSi.Alternatively, if first conductive layer 504 and second conductive layer 510 are to be formed by metal level, metal gate layers 511 can be formed by polysilicon/WN/WSi.
Should be understood that the above embodiment of the present invention also can be applicable to TANOS (tantalum/Al
2O
3/ nitride/oxide/silicon) type Nonvolatile memory devices and SONOS type and MANOS type Nonvolatile memory devices.
According to the first embodiment of the present invention,, in each memory cell, form electric charge capture layer through electric charge capture layer is carried out Patternized technique.Can prevent that the electric charge that is stored in electric charge capture layer is diffused into contiguous memory cell.Correspondingly, it can reduce the generation such as the problem of potential energy decline, threshold voltage shift and data retention characteristics degeneration etc. that when charge stored in the electric charge capture layer moves to contiguous memory cell, produces.
According to a second embodiment of the present invention, electric charge capture layer is formed in the space between the separator in the isolated area of Semiconductor substrate.This can prevent that when programming operation the electric charge that is trapped in the electric charge capture layer moves in the adjacent unit grid.Correspondingly, can improve programmed threshold voltage, and improve the retention performance of unit thus.
A third embodiment in accordance with the invention before forming separator through subsequent technique, is formed at electric charge capture layer on the Semiconductor substrate.Through this separator, the charge storing unit capture layer is along the electric charge capture layer electric isolation of bit line direction and adjoining memory cell.This can prevent that when programming operation the electric charge that is trapped in the electric charge capture layer moves in the adjacent unit grid.Correspondingly, can improve programmed threshold voltage, and improve the retention performance of unit thus.Further, in the unit area, form after the passivation dielectric layer,, in outer peripheral areas, be formed for the tunnel dielectric layer of high voltage transistor or low-voltag transistor through the thickness of control tunnel dielectric layer.Correspondingly, can easily form high voltage or low-voltag transistor.
The foregoing description purpose in this announcement is to make those skilled in the art's embodiment of the present invention easily, and those skilled in the art can come embodiment of the present invention through combination the foregoing description.Therefore, protection scope of the present invention is not limited to the above embodiments, and is only explained claim and equivalent feature thereof and limit.
The application requires the priority of korean patent application 2007-63605 that submits in the korean patent application 2007-28001 that submitted on March 22nd, 2007, the korean patent application 2007-42979 of submission on May 3rd, 2007, on June 27th, 2007 and the korean patent application 2007-91555 that submitted on September 10th, 2007, and its full content is quoted and is incorporated into this.
Claims (21)
1. method of making non-volatile memory device, said method comprises:
On the surface of the Semiconductor substrate that comprises outstanding separator, form first dielectric layer and electric charge capture layer, wherein said electric charge capture layer is formed by nitride layer;
Said first dielectric layer and said electric charge capture layer are carried out glossing to expose the end face of said outstanding separator, make said first dielectric layer and said electric charge capture layer be retained in said Semiconductor substrate by on the defined active area of said outstanding separator;
On said electric charge capture layer and said separator, form second dielectric layer; And
On said second dielectric layer, form conductive layer.
2. the method for claim 1 wherein forms said outstanding separator and comprises in said Semiconductor substrate:
On said Semiconductor substrate, form pad nitride layer;
On said pad nitride layer, form first mask pattern, said first mask pattern has and the corresponding open area of said separator;
Use said first mask pattern to come the said pad nitride layer of patterning and in said Semiconductor substrate, form groove; And
With the said groove of filling insulating material to form said separator.
3. the method for claim 1, wherein said electric charge capture layer is formed by insulating material.
4. the method for claim 1, wherein said first dielectric layer is a tunnel insulation layer, said second dielectric layer is that barrier layer and said conductive layer are the control grids.
5. method of making non-volatile memory device, said method comprises:
Order forms insulating barrier and hard mask layer on Semiconductor substrate;
Through using said hard mask layer to come the said Semiconductor substrate of etching, thereby form groove as the etch process of etching mask;
Use the said groove of filling insulating material and form separator;
Remove said insulating barrier and said hard mask layer, thereby form outstanding separator;
On the whole surface of the said semiconductor underlayer that comprises said separator, form tunnel dielectric layer, electric charge capture layer and buffering dielectric layer, wherein said electric charge capture layer is formed by the silicon nitride or the persilicic nitride of stoichiometric proportion; And
Said buffer medium layer, said electric charge capture layer and said tunnel dielectric layer are carried out the end face that glossing exposes said outstanding separator, make said tunnel dielectric layer and said electric charge capture layer be retained in said Semiconductor substrate by on the defined active area of said outstanding separator.
6. method as claimed in claim 5 also comprises:
Form passivation dielectric layer comprising on the said hard mask layer of said separator,
Wherein said passivation dielectric layer is removed in the step that forms outstanding separator removing said insulating barrier and said hard mask layer.
7. method as claimed in claim 5 also is included in after the glossing, sequentially piles up barrier insulating layer, metal level and gate electrode layer comprising on the whole surface of said electric charge capture layer and said separator.
8. method as claimed in claim 7 also comprises: before forming said barrier insulating layer and gate electrode layer, remove said buffer medium layer.
9. method as claimed in claim 6, wherein said passivation dielectric layer be through low-pressure chemical vapor deposition or plasma enhanced chemical vapor deposition method, is that the nitride layer of 200 to 4000 dusts forms by thickness.
10. method as claimed in claim 5, the projecting height of wherein said separator is in the scope of 200 to 800 dusts.
11. method as claimed in claim 5, wherein said tunnel dielectric layer forms through dry method thermal oxidation technology, means of wet thermal oxidation technology or free-radical oxidation technology.
12. method as claimed in claim 5, the height of wherein said electric charge capture layer is lower than the height of the end face of said separator.
13. method as claimed in claim 5, wherein said electric charge capture layer is through low-pressure chemical vapor deposition or plasma enhanced chemical vapor deposition method, and forming thickness is 40 to 200 dusts.
14. method as claimed in claim 5, wherein said buffer medium layer are that high density plasma oxide layer, spin-coating glass, undoped silicate glass, phosphosilicate glass or the boron phosphorus silicate glass of 500 to 4000 dusts forms by thickness.
15. a method of making non-volatile memory device, said method comprises:
Form first tunnel dielectric layer and electric charge capture layer on Semiconductor substrate, definition has unit area and outer peripheral areas in the said Semiconductor substrate, and wherein said electric charge capture layer is formed by the mixed layer or the nitride layer of oxide skin(coating) and nitride layer;
On said electric charge capture layer, form the barrier insulating layer and first conductive layer;
Through said first conductive layer of etching, barrier insulating layer, electric charge capture layer, first tunnel dielectric layer and Semiconductor substrate to form isolated groove;
Use the said isolated groove of filling insulating material to form outstanding separator;
On said first conductive layer of said unit area, form passivation dielectric layer;
After removing said first conductive layer, barrier insulating layer and the electric charge capture layer of said outer peripheral areas, etching is formed at the outstanding end face of the said separator in the said outer peripheral areas, thereby controls the height of said separator;
On the said tunnel dielectric layer of said outer peripheral areas, form second tunnel dielectric layer; And
Remove said passivation dielectric layer.
16. method as claimed in claim 15 also comprises: after having formed said second tunnel dielectric layer, forming conductive layer on second tunnel dielectric layer of said outer peripheral areas and on second tunnel dielectric layer in said unit area.
17. method as claimed in claim 15, wherein said passivation dielectric layer is formed by nitride layer.
18. method as claimed in claim 15; Wherein for the situation of high voltage transistor; Be used for the thickness that transistorized said second tunnel dielectric layer forms 500 to 600 dusts; And, be used for the thickness that transistorized said second tunnel dielectric layer forms 500 to 200 dusts for the situation of low-voltag transistor.
19. method as claimed in claim 15 also comprises: carry out rapid thermal treatment to improve the film quality of said barrier insulating layer.
20. method as claimed in claim 15 also comprises: after forming said first conductive layer, before forming said isolated groove, in said electric charge capture layer, inject ion through carrying out ion implantation technology.
21. method as claimed in claim 15, wherein said ion implantation technology use As or P as impurity.
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020070028001A KR100966989B1 (en) | 2007-03-22 | 2007-03-22 | Method of manufacturing in Flash memory device |
| KR28001/07 | 2007-03-22 | ||
| KR42979/07 | 2007-05-03 | ||
| KR20070042979 | 2007-05-03 | ||
| KR63605/07 | 2007-06-27 | ||
| KR1020070063605A KR100966988B1 (en) | 2007-06-27 | 2007-06-27 | Non-volatile memory device and method of fabricating the same |
| KR91555/07 | 2007-09-10 | ||
| KR1020070091555A KR101017506B1 (en) | 2007-05-03 | 2007-09-10 | Semiconductor memory device and method of manufacturing thereof |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008101428567A Division CN101308824A (en) | 2007-03-22 | 2008-03-24 | Nonvolatile memory device and method of fabricating the same |
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| CN102664168A true CN102664168A (en) | 2012-09-12 |
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| US6404020B1 (en) * | 1998-07-31 | 2002-06-11 | Samsung Electronics Co., Ltd. | Method of forming contact pads in a semiconductor device and a semiconductor device formed using the method |
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Application publication date: 20120912 |