CN100343980C - Non-volatile memory element and its making method - Google Patents

Non-volatile memory element and its making method Download PDF

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Publication number
CN100343980C
CN100343980C CNB200410033247XA CN200410033247A CN100343980C CN 100343980 C CN100343980 C CN 100343980C CN B200410033247X A CNB200410033247X A CN B200410033247XA CN 200410033247 A CN200410033247 A CN 200410033247A CN 100343980 C CN100343980 C CN 100343980C
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memory element
layer
volatile memory
substrate
grid
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CN1677647A (en
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许汉杰
张格荥
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Powerchip Semiconductor Corp
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Powerchip Semiconductor Corp
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Abstract

The present invention relates to a non-volatile memory element and a manufacture method thereof, wherein first, the manufacture method provides one substrate, and then, one groove is formed in the substrate. Subsequently, one bottom oxide layer, one charge trapping layer and one top oxide layer are orderly formed on the surfaces of the substrate and the groove. Thereafter, one conductive layer is formed on the top oxide layer to fill the groove, and the conductive layer is defined to form one grid on the groove. Thereafter, the top oxide layer, the charge trapping layer and the bottom oxide layer which are outside the grid are removed, and one source/drain adulterate manufacture technique is carried out. Because the memory element is manufactured in the groove by the present invention, the storing efficiency of the memory element can be improved by increasing a coupling rate, and a plurality of charge numbers are stored by adjusting the depth of the groove.

Description

Non-volatile memory element and manufacture method thereof
Technical field
The present invention relates to a kind of manufacture method of memory element, particularly relate to a kind of non-volatile memory element (non-volatile memory device) and manufacture method thereof.
Background technology
In various non-volatility memorizer products, has the actions such as depositing in, read, erase that to carry out repeatedly data, and can erasing and programmable read only memory (EEPROM) by electricity of the advantage that the data that deposit in also can not disappear after outage, become personal computer and electronic equipment a kind of memory assembly of extensively adopting.Typically can erase and polysilicon (polysilicon) the making floating grid (floating gate) and control grid (control gate) of programmable read only memory by electricity to mix.When memory was programmed (program), the electronics that injects floating grid can be uniformly distributed among the whole polysilicon floating gate layer.Yet the tunnel oxide (tunneling oxide) below the polysilicon floating gate layer just causes the leakage current of assembly when defectiveness exists easily, influences the reliability of assembly.
Therefore, in order to solve the problem of the programmable read only memory assembly leakage current of can electric erasing, present method is to adopt a charge immersing layer (charge trapping layer) to replace the polysilicon floating gate of existing memory, and the material of this charge immersing layer for example is a silicon nitride.This silicon nitride charge immersing layer respectively has one deck silica up and down usually, and form a kind of silicon oxide/silicon nitride/silicon oxide (oxide-nitride-oxide that comprises, be called for short ONO) layer stacked structures (stacked structure) that is constituted, read-only memory with this stack type grid structure can be described as silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon (silicon-oxide-nitride-oxide-silicon is called for short SONOS) memory element.
This kind silicon/oxidative silicon/the nitrogenize silicon/oxidative silicon/the silicon memory element as shown in Figure 1.Please refer to Fig. 1, silicon monoxide/silicon nitride/silicon oxide layer 102 is arranged on substrate 100, the stacked structures that it is made of an end silicon oxide layer 104, a silicon nitride layer 106 and a top silicon oxide layer 108.In addition, one polysilicon gate 112 is arranged on silicon oxide/silicon nitride/silicon oxide layer 102, just as character line (word line), and in the substrate 100 of silicon oxide/silicon nitride/silicon oxide floor 102 both sides, having source electrode or drain electrode (source/drain) district 118, it is as embedded type bit line (buried bit line).Moreover, in the common gapped wall 116 of polysilicon gate 112 sidewalls, and there are shallow doped region (lightly doping region) 114 and source electrode or drain region 118 to be electrical connected in the substrate 100 below clearance wall 116.
But the general mat of silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon memory element is via channel hot electron (the channel hot electron of the bottom oxide 104 of silicon oxide/silicon nitride/silicon oxide layer 102, be called for short CHE) inject and by sequencing, and during sequencing, electric charge can be caught in the silicon oxide/silicon nitride/silicon oxide layer 102.Moreover, but silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon memory element mat increases hot hole (tunneling enhanced hothole is called for short TEHH) and injects and erased via the tunnel of wearing of the bottom oxide 104 of silicon oxide/silicon nitride/silicon oxide layer 102.And the efficiency of storage of silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon memory element mainly is influenced by its coupling efficiency; The contact area of just aforementioned top silicon oxide layer 108 and polysilicon gate 112.
Yet, development trend along with component miniaturization, the live width of assembly is also dwindled in the lump, thereby causes the silicon/oxidative silicon/top silicon oxide layer of nitrogenize silicon/oxidative silicon/silicon memory element and the contact area of polysilicon gate to be dwindled, and makes its efficiency of storage be affected and variation.So will how under the trend of component miniaturization, increase the coupling efficiency of silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon memory element, and then promote its efficiency of storage at present, will be one of emphasis of all circles' research.
Summary of the invention
Therefore, the purpose of this invention is to provide a kind of manufacture method of non-volatile memory element, produce non-volatile memory element than effectively high coupling ratios with the development of matable assembly miniaturization.
Another object of the present invention provides a kind of non-volatile memory element, effectively dwindling size of components, and increases the coupling efficiency of non-volatile memory element, and then promotes its efficiency of storage.
According to above-mentioned and other purpose, the present invention proposes a kind of manufacture method of non-volatile memory element, and a substrate is provided earlier, forms a groove again in substrate.Subsequently, form a bottom oxide, a charge immersing layer and a top oxide layer in regular turn in substrate and flute surfaces.Afterwards, on the oxide layer of top, form a conductive layer and fill up groove, define conductive layer again, on groove, to form a grid.Afterwards, remove grid top oxide layer, charge immersing layer and bottom oxide in addition, carry out one source pole or drain electrode doping manufacturing process again.
The present invention proposes a kind of non-volatile memory element in addition, comprises a substrate, a grid, a bottom oxide, a charge immersing layer, a top oxide layer and several source electrodes or drain region, and wherein substrate has a groove.And grid is positioned on the groove and fill up groove, and bottom oxide then is between grid and flute surfaces.Charge immersing layer is between grid and bottom oxide, and the top oxide layer is between grid and charge immersing layer.Source electrode or drain region then are arranged in the substrate in the grid outside.
The present invention is because be made in non-volatile memory element in the silicon trench, thus can under fixing size of components, increase its coupling efficiency, and then promote the efficiency of storage of memory element.And, because the degree of depth of groove can adjust, so it is many to deposit the more existing non-volatile memory element of the charge number of this kind memory element in; Just, the threshold voltage of programming (program) (threshold voltage is called for short Vt) can be adjusted by gash depth.In addition, manufacturing process of the present invention simply promptly belongs to single-polysilicon manufacturing process (single poly process), so also can be used for flush type (embedded) manufacturing process.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and cooperate institute's accompanying drawing to elaborate.
Description of drawings
Fig. 1 illustrate is the profile of existing silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon memory element.
Fig. 2 A to Fig. 2 D is the manufacturing process profile according to a kind of non-volatile memory element of a preferred embodiment of the present invention.
Fig. 3 is the generalized section of groove of another example of non-volatile memory element of the present invention.
The simple symbol explanation
100,200,300: substrate
102,210,210a: silicon oxide/silicon nitride/silicon oxide layer
104,108,204,208: silicon oxide layer
106: silicon nitride layer
112,212a: grid
114,214: shallow doped region
116,216: clearance wall
118,218: source electrode or drain region
202,302: groove
206: charge immersing layer
212: conductive layer
213: shallow doping manufacturing process
217: source electrode or drain electrode doping manufacturing process
Embodiment
Fig. 2 A to Fig. 2 D is the manufacturing process profile according to a kind of non-volatile memory element of a preferred embodiment of the present invention.
Please refer to Fig. 2 A, a substrate 200 is provided earlier, in substrate 200, form a groove 202 again.And the step that forms groove 202 in substrate 200 for example is prior to forming a pad oxide (pad oxide on the substrate 200, do not illustrate), on pad oxide, form a patterned mask layer (pattemed masklayer again, do not illustrate), its material for example is silicon nitride or other suitable material.Subsequently, be mask with the patterned mask layer, remove the pad oxide and the part substrate 200 that expose.Afterwards, treat to need aforementioned pad oxide and patterned mask layer are removed after groove 202 formation.
Then, please refer to Fig. 2 B, form a bottom oxide 204 in substrate 200 and groove 202 surfaces, its material comprises silica, and this bottom oxide 204 for example utilizes a thermal oxidation manufacturing process to form.Afterwards, on bottom oxide 204, form a charge immersing layer (charge trapping layer) 206, its material is a silicon nitride for example, and this charge immersing layer 206 is to utilize a chemical vapour deposition (CVD) (chemicalvapor deposition for example, being called for short CVD) manufacturing process forms, and charge immersing layer 206 can also be that other is as nitration case, tantalum oxide layers, strontium titanate layer or hafnium oxide layer etc.Subsequently, form a top oxide layer 208 on charge immersing layer 206, its material comprises silica.And the stacked structures that aforesaid bottom oxide 204, charge immersing layer 206 and top oxide layer 208 are constituted such as this figure silicon monoxide/silicon nitride/silicon oxide layer 210, non-volatile memory element with this stacked structures can be described as silicon/oxidative silicon/nitrogenize silicon/oxidative silicon/silicon (silicon-oxide-nitride-oxide-silicon is called for short SONOS) memory element.Then, on top oxide layer 208, form a conductive layer 212 and fill up groove 202, wherein for example polysilicon (polysilicon) or other suitable material of the material of conductive layer 212.
Afterwards, please refer to Fig. 2 C, definition conductive layer 212 is to form a grid 212a on groove 202.And grid 212a can select to extend on the groove 202 part substrate 200 outward (as shown in this figure), or directly is formed on the groove 202.Then, remove bottom oxide 204, charge immersing layer 206 and top oxide layer 208 beyond the grid 212a, remain then as silicon oxide/silicon nitride/silicon oxide layer 210a.Then, can select to carry out a shallow doping manufacturing process (lightly doping process) 213, in the substrate 200 in the grid 212a outside, to form shallow doped region (lightly doping region) 214.
Then, please refer to Fig. 2 D, optionally form several clearance walls 216 in grid 212a sidewall, its material is silicon nitride or other suitable material for example.Afterwards, carry out one source pole or drain electrode doping manufacturing process (source/drain doping process) 217, to form several source electrodes or drain region (source/drain region) 218 in the substrate 200 outside the clearance wall 216 of grid 212a sidewall.In addition, after source electrode or drain electrode doping manufacturing process 217, still can comprise that carrying out one aims at metal silicide (self-alignedsilicide voluntarily, be abbreviated as salicide) manufacturing process, to form a metal silicide layer (not illustrating), wherein suitable materials such as the material of metal silicide layer such as cobalt silicide, titanium silicide, tungsten silicide, molybdenum silicide, platinum silicide or nickle silicide in grid 212a surface.And, usually before aiming at the silicide manufacturing process voluntarily, also can be included in and form one on the part substrate 200 and aim at blocking layer of metal silicide (salicideblock is called for short SAB) voluntarily, so that cover the zone that need not form metal silicide.
In addition, groove 202 shapes can also be a kind of grooves with shape of sliding suitable (smooth) change except shown in Fig. 2 A~2D, as shown in Figure 3, are beneficial to follow-up deposition as bottom oxide.Please refer to Fig. 3, the groove 302 that is formed in the substrate 300 is obviously different with groove 202 sections of Fig. 2 A~2D, and presents the shape of sliding Hue.
In sum, one of characteristics of the present invention are non-volatile memory element is made in the silicon trench, thus under same size of components and live width, can increase its coupling efficiency, and then promote efficiency of storage.And, because gash depth can adjust, so the charge number that can deposit in is more; That is to say that (threshold voltage Vt) can adjust by gash depth memory element at the start voltage of (program) of programming.In addition, manufacturing process of the present invention simply promptly belongs to single-polysilicon manufacturing process (single polyprocess), so also can be used for flush type (embedded) manufacturing process.
Though the present invention discloses as above with preferred embodiment; yet it is not in order to limit the present invention; those skilled in the art can do a little change and retouching without departing from the spirit and scope of the present invention, thus protection scope of the present invention should with accompanying Claim the person of being defined be as the criterion.

Claims (18)

1. the manufacture method of a non-volatile memory element comprises:
One substrate is provided;
In this substrate, form a groove;
Form a bottom oxide in this substrate and this flute surfaces;
On this bottom oxide, form a charge immersing layer;
On this charge immersing layer, form a top oxide layer;
On this top oxide layer, form a conductive layer and fill up this groove;
Define this conductive layer, on this groove, to form a grid;
Remove this grid this top oxide layer, this charge immersing layer and this bottom oxide in addition; And
Carry out one source pole or drain electrode doping process.
2. the manufacture method of non-volatile memory element as claimed in claim 1 wherein forms before this groove in this substrate, also comprises the active area of isolating on this substrate.
3. the manufacture method of non-volatile memory element as claimed in claim 1 wherein forms the step of this bottom oxide in this substrate and this flute surfaces, comprise and utilize a thermal oxidation technology to form one silica layer in this substrate and this flute surfaces.
4. the manufacture method of non-volatile memory element as claimed in claim 1 wherein forms the step of this charge immersing layer on this bottom oxide, comprise and utilize a chemical vapor deposition method to form a silicon nitride layer on this bottom oxide.
5. the manufacture method of non-volatile memory element as claimed in claim 1, wherein carry out also comprising before this source electrode or the drain electrode doping process:
Carry out a shallow doping process; And
Form a plurality of clearance walls in this gate lateral wall.
6. the manufacture method of non-volatile memory element as claimed in claim 1, the step that wherein defines this conductive layer also is included on outer this substrate of part of this groove and forms this grid.
7. the manufacture method of non-volatile memory element as claimed in claim 1 wherein carries out comprising that also carrying out one aims at the metal silicide manufacturing process voluntarily, to form a metal silicide layer in this gate surface after this source electrode or the drain electrode doping manufacturing process.
8. the manufacture method of non-volatile memory element as claimed in claim 7 is wherein carried out this and is aimed at voluntarily before the silicide manufacturing process, also is included in to form one on this substrate of part and aim at blocking layer of metal silicide voluntarily.
9. non-volatile memory element comprises:
One substrate, this substrate has a groove;
One grid is positioned on this groove and fills up this groove;
One bottom oxide is between this grid and this flute surfaces;
One charge immersing layer is between this grid and this bottom oxide;
One top oxide layer is between this grid and this charge immersing layer; And
A plurality of source electrodes or drain region are arranged in this substrate in this grid outside, and not below this grid.
10. non-volatile memory element as claimed in claim 9, wherein this grid also comprises on this substrate of part that extends outside this groove.
11. non-volatile memory element as claimed in claim 10, wherein this bottom oxide also comprises between this grid and this substrate.
12. non-volatile memory element as claimed in claim 9 also comprises a plurality of clearance walls, is positioned at the sidewall of this grid.
13. non-volatile memory element as claimed in claim 12 also comprises a plurality of shallow doped regions, is arranged in this substrate of this a plurality of clearance walls below.
14. non-volatile memory element as claimed in claim 12, wherein the material of these a plurality of clearance walls comprises silicon nitride.
15. non-volatile memory element as claimed in claim 9, wherein the material of this grid comprises polysilicon.
16. non-volatile memory element as claimed in claim 9, wherein the material of this charge immersing layer is selected from a group that is made up of nitration case, tantalum oxide layers, strontium titanate layer and hafnium oxide layer.
17. non-volatile memory element as claimed in claim 9 also comprises a metal silicide layer, is positioned at this gate surface.
18. non-volatile memory element as claimed in claim 17, wherein the material of this metal silicide layer is selected from a group that is made up of cobalt silicide, titanium silicide, tungsten silicide, molybdenum silicide, platinum silicide and nickle silicide.
CNB200410033247XA 2004-03-29 2004-03-29 Non-volatile memory element and its making method Expired - Fee Related CN100343980C (en)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1407626A (en) * 2001-09-06 2003-04-02 旺宏电子股份有限公司 Vertical nitride read out-only memory unit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1407626A (en) * 2001-09-06 2003-04-02 旺宏电子股份有限公司 Vertical nitride read out-only memory unit

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