CN1264218C - Separate-gate flash memory unit and its making process - Google Patents
Separate-gate flash memory unit and its making process Download PDFInfo
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- CN1264218C CN1264218C CN02103510.5A CN02103510A CN1264218C CN 1264218 C CN1264218 C CN 1264218C CN 02103510 A CN02103510 A CN 02103510A CN 1264218 C CN1264218 C CN 1264218C
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- 238000000034 method Methods 0.000 title claims description 13
- 239000000758 substrate Substances 0.000 claims abstract description 38
- 239000000725 suspension Substances 0.000 claims abstract description 33
- 239000002784 hot electron Substances 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 13
- 229910052710 silicon Inorganic materials 0.000 claims description 13
- 239000010703 silicon Substances 0.000 claims description 13
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 10
- 229920005591 polysilicon Polymers 0.000 claims description 10
- 239000012212 insulator Substances 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 2
- 238000009413 insulation Methods 0.000 claims description 2
- 230000005684 electric field Effects 0.000 description 11
- 230000004888 barrier function Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- GWFXMCXJFOEMNQ-UHFFFAOYSA-N [O].O=[N] Chemical compound [O].O=[N] GWFXMCXJFOEMNQ-UHFFFAOYSA-N 0.000 description 1
- WDBZLBMLUXGRIQ-UHFFFAOYSA-N [O].[N].[Si]=O Chemical compound [O].[N].[Si]=O WDBZLBMLUXGRIQ-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- NHDHVHZZCFYRSB-UHFFFAOYSA-N pyriproxyfen Chemical compound C=1C=CC=NC=1OC(C)COC(C=C1)=CC=C1OC1=CC=CC=C1 NHDHVHZZCFYRSB-UHFFFAOYSA-N 0.000 description 1
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Abstract
The present invention relates to a separate-gate quick-flashing memory device and a manufacturing method thereof. The device comprises a substrate, a suspension joint gate electrode, a control gate electrode and a ladder pad, wherein the suspension joint gate electrode is positioned above the substrate and is insulated with the substrate, the control gate electrode is positioned above the suspension joint gate electrode and is insulated with the suspension joint gate electrode, the ladder pad is positioned on the substrate, is connected with the substrate and is close to the suspension joint gate electrode, and hot electrons and the substrate are formed into the parallel direction to be injected in the suspension joint gate electrode by the ladder pad during the write operation.
Description
Technical field
The present invention relates to the manufacturing technology of semiconductor transistor, especially a kind of the reduction writes bias voltage and quickening writes and the split-gate flash memory device and the manufacture method thereof of the speed of erasing.
Background technology
Fig. 1 has shown the profile of a traditional split-gate flash memory device.Comprising a silicon base 11, be stacked over suspension joint grid 13 on the silicon base 11, control grid 15 and select grid 19.Between each grid, have insulating barrier 12,14,16,18 and clearance wall 17 respectively.Insulating barrier 12,18 and clearance wall 17 are silicon oxide layer, and insulating barrier 14 then is oxygen-nitrogen-silicon oxide layer (ONO), and insulating barrier 16 is a silicon nitride layer.In addition, have source/drain doping region 111 in the silicon base 11, it is connected to carry out the action that memory contents reads with a connector 20.
Above-mentioned traditional split-gate flash memory device is when carrying out write activity, system utilizes the electric field that voltage causes between a among Fig. 1, b, c at 3, in substrate 11, produce hot electron (hot electron), and collect, and make the suspension joint grid have different current potentials with the store digital data by the suspension joint grid.Wherein, the voltage of a, b point-to-point transmission is in order to the generation hot electron, and the voltage of a, c point-to-point transmission enters the suspension joint grid in order to become to making those hot electrons.In addition, when erasing, also utilize the voltage between a, c to become to making the electronics that before has been stored in the suspension joint grid to flow in the substrate 11.
Yet, because higher writing speed need possess high hot electron output capacity simultaneously and collection rate just can be reached, and in above-mentioned traditional split-gate flash memory device, (b → a and a → c) are vertical mutually to influence the direction of an electric field of hot electron output capacity and collection rate, the voltage difference that therefore must increase simultaneously between c, a just can be reached with the voltage difference between a, b, and meaning promptly needs add a high voltage controlling on the grid 15.So high voltage needs more electric charge circuit (charge pump circuit) of heap of stone, and causes circuit area to increase.Therefore, when making traditional split-gate flash memory device, must between writing speed and bias value, circuit area, make trade-offs, can't get both.
Summary of the invention
In order to address the above problem, the invention provides a kind of split-gate flash memory device and manufacture method thereof, the electric field of its decision hot electron generation rate is identical with decision hot electron collection rate direction of an electric field, and under same writing speed condition, the bias value that its control grid needs is lower.
A purpose of the present invention is to provide a kind of split-gate flash memory device, comprises a substrate, a suspension joint grid, control grid, a step pad and one a source/drain region.Wherein, the suspension joint grid is positioned at this substrate top and insulate with this substrate.The control grid be positioned at this suspension joint grid top and with this suspension joint gate insulator.Step pad is positioned in this substrate and is connected and contiguous this control grid with this substrate, and when carrying out write activity, hot electron becomes a parallel direction to inject this suspension joint grid via this step pad with this substrate.Source/drain region is arranged in this step pad.
Another object of the present invention is to provide a kind of manufacture method of split-gate flash memory device, may further comprise the steps: a substrate is provided.The suspension joint grid of formation one and this substrate insulation in this substrate.The control grid of formation one and this suspension joint gate insulator on this suspension joint grid.In this substrate, form a step pad that is connected and is close to this suspension joint grid with this substrate.In this step pad, form one source/drain doping region.
By this, in the present invention, in substrate, form a step pad, make hot electron in step pad, become parallel direction generation with substrate with one, it is identical with the direction of collecting the hot electron electric field that this produces thermionic electric field, directly help thermionic collection, therefore, reduced the bias value that the control grid needs.
Description of drawings
Fig. 1 has shown the profile of a traditional split-gate flash memory device;
Fig. 2 A to Fig. 2 F ' has shown the manufacturing process of split-gate flash memory device in one embodiment of the invention.
Symbol description:
11,21～silicon base; 12,22～gate oxidation silicon layer;
13,23～suspension joint grid; 14,24～oxygen-nitrogen-silicon oxide layer;
15,25～control grid; 16,26～silicon nitride layer;
17,28,30～clearance wall; 271,272～groove;
19,34～selection grid; 20,32～connector;
29～step pad; 31,33～oxide layer.
Embodiment
Fig. 2 A to Fig. 2 F has shown the manufacturing process of split-gate flash memory device in the present embodiment.
At first, shown in Fig. 2 A, provide a silicon base 21.
Then, shown in Fig. 2 B, on silicon base 21, deposit a grid oxic horizon 22, a polysilicon layer 23 as the suspension joint grid, one oxygen-nitrogen-oxide layer 24, a polysilicon layer 25 and a silicon nitride layer 26 as the control grid in regular turn.
Then, shown in Fig. 2 C, etching is stacked over the sedimentary deposit 22,23,24,25 and 26 on the silicon base 21, forms the groove 271 and 272 that exposes silicon base 21 to the open air.Deposit a HTO oxide layer 28 again and eat-back and form clearance walls (spacer) 28 at groove 271,272 sidewalls.
Come again, shown in Fig. 2 D, utilize selectivity oriented growth method (Selective Epitaxial Growth is called for short SEG) on the silicon base 21 of groove 271,272 bottoms, to form the polysilicon layer 29 that is connected with silicon base 21, as the usefulness of step pad (stepped substrate).Deposit a HTO oxide layer 30 again and eat-back, and form clearance wall 30, then step pad 29 is carried out oxidation, generation oxide layer 31 in groove 271,272 sidewalls.Then utilize a photoresist layer (figure show) to be shielding, cover groove 272 and the oxide layer in the groove 271 31 is carried out etching and removed oxide layer 31, utilize ionic-implantation formation source/drain doping region 291 in the step pad 29 of groove 271 then.
Then, shown in Fig. 2 E, deposit a polysilicon layer 32 and eat-back and fill up groove 271,272.Utilize photoresist layer (figure show) to be shielding, cover the polysilicon layer 32 in the groove 272 and make polysilicon layer 32 in the groove 271 oxidized and produce oxide layer 33.Polysilicon layer 32 in the groove 271 is as the usefulness of the connector of connection source/drain doping region 291.
At last, shown in Fig. 2 F, deposition one is the polysilicon layer 34 used of grid alternatively.
Fig. 2 F ' shows the partial enlarged drawing of step pad 29 in the present embodiment.Shown in Fig. 2 F ', because the existence of step pad 29, make the position change of in traditional split-gate flash memory device a, b, c.Parallel in order to produce thermionic direction of an electric field b → a with substrate 21, and also parallel in order to collect thermionic direction of an electric field a → c with substrate 21.So, producing thermionic electric field can be identical with the hot electron collecting direction, makes that thermionic collection is not the electric field that only depends on c, a point-to-point transmission voltage difference to be produced, and is attended by the subsidy of b, a point-to-point transmission electric field.Therefore, under identical writing speed condition, the required just more traditional split-gate flash memory device of current potential of c point comes lowly, and meaning is that the needed bias value of its control grid is lower.
Though the present invention discloses as above with a preferred embodiment; right its is not in order to limiting the present invention, anyly has the knack of this skill person, without departing from the spirit and scope of the present invention; when can doing a little change and retouching, thus protection scope of the present invention when with claims the person of being defined be as the criterion.
Claims (12)
1. split-gate flash memory device is characterized in that: comprising:
One substrate;
One suspension joint grid is positioned at above this substrate and with this substrate and insulate;
One control grid, be positioned at this suspension joint grid top and with this suspension joint gate insulator;
One step pad is positioned in this substrate and is connected with this substrate and contiguous this control grid, and when carrying out write activity, hot electron becomes a parallel direction to inject this suspension joint grid via this step pad with this substrate; And
One source/drain region is arranged in this step pad.
2. split-gate flash memory device as claimed in claim 1 is characterized in that: more comprise a connector, be connected with this source/drain electrode and with this control grid and suspension joint gate insulator.
3. split-gate flash memory device as claimed in claim 1 is characterized in that: comprise that more one selects grid, be positioned at above this control grid and with this control gate insulator.
4. split-gate flash memory device as claimed in claim 1 is characterized in that: this substrate is a silicon base.
5. split-gate flash memory device as claimed in claim 1 is characterized in that: this suspension joint grid layer, this control grid layer and this step pad are polysilicon layer.
6. split-gate flash memory device as claimed in claim 1 is characterized in that: when erasing action, the electronics in this control grid also injects this substrate via this step pad.
7. the manufacture method of a split-gate flash memory device is characterized in that: may further comprise the steps:
One substrate is provided;
The suspension joint grid of formation one and this substrate insulation in this substrate;
The control grid of formation one and this suspension joint gate insulator on this suspension joint grid;
In this substrate, form a step pad that is connected and is close to this suspension joint grid with this substrate; And
In this step pad, form one source/drain doping region.
8. the manufacture method of split-gate flash memory device as claimed in claim 7 is characterized in that: more be included in and form a connector that is connected with this source/drain doping region on this source/drain doping region.
9. the manufacture method of split-gate flash memory device as claimed in claim 7 is characterized in that: more may further comprise the steps:
Formation one is controlled the selection grid of gate insulator with this on this control grid.
10. the manufacture method of split-gate flash memory device as claimed in claim 7, it is characterized in that: this substrate is a silicon base.
11. the manufacture method of split-gate flash memory device as claimed in claim 7 is characterized in that: this suspension joint grid, this control grid and this step pad are polysilicon layer.
12. the manufacture method of split-gate flash memory device as claimed in claim 7 is characterized in that: this step pad forms via selectivity oriented growth method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN02103510.5A CN1264218C (en) | 2002-02-05 | 2002-02-05 | Separate-gate flash memory unit and its making process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN02103510.5A CN1264218C (en) | 2002-02-05 | 2002-02-05 | Separate-gate flash memory unit and its making process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1437259A CN1437259A (en) | 2003-08-20 |
| CN1264218C true CN1264218C (en) | 2006-07-12 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN02103510.5A Expired - Lifetime CN1264218C (en) | 2002-02-05 | 2002-02-05 | Separate-gate flash memory unit and its making process |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108666315B (en) * | 2017-03-31 | 2021-06-11 | 上海格易电子有限公司 | Flash memory and manufacturing method thereof |
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- 2002-02-05 CN CN02103510.5A patent/CN1264218C/en not_active Expired - Lifetime
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