CN101202309A

CN101202309A - Floating gate flash memory device

Info

Publication number: CN101202309A
Application number: CNA2006101194014A
Authority: CN
Inventors: 金勤海
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2006-12-11
Filing date: 2006-12-11
Publication date: 2008-06-18

Abstract

The invention discloses a floating-gate flash memory device which comprises a source electrode and a drain electrode; wherein, a poly-silicon floating-gate and a control grid are arranged above the gap between the source electrode and the drain electrode, and a silicon dioxide layer is arranged between the floating-gate and the source electrode and the drain electrode; the floating-gate is a concave shape, the two ends of which are upward provided with protuberant cusps, and is completely covered by the control grid, and a silicon dioxide is arranged between the floating-gate and the control grid. The floating-gate flash memory device of the invention has the advantages of greatly improving the 'read' and 'wipe' working efficiency of the flash memory device, and improving the performance of the device.

Description

Floating gate flash memory device

Technical field

The present invention relates to a kind of floating gate flash memory device.

Background technology

Course of work when existing floating gate flash memory carries out " writing " operation can be referring to shown in Figure 1, add on the control gate 5 that certain voltage makes the raceway groove conducting between source electrode 2 and the drain electrode 1, drain electrode 1 connects high voltage, source electrode 2 connects low-voltage, electronics flows to drain electrode 1 and quicken to produce hot electron under near the high electric field action drain electrode 1 from source electrode 2, and the silicon dioxide layer 3 that the portion of hot electronics passes below the floating boom 4 enters floating boom 4.And when carrying out " wiping " operation, as shown in Figure 2, control gate 5 connects low-voltage, and source electrode 2 and drain electrode 1 connect high voltage, and electronics passes silicon dioxide layer 3 from floating boom 4 and flows into source electrode 2.Because " wiping " and " writing " shared layer of silicon dioxide layer 3, it is independent respectively to make that " wiping " and " writing " is not easy, so operating efficiency can't improve.

Summary of the invention

Technical problem to be solved by this invention provides a kind of floating gate flash memory device structure, and can increase substantially flush memory device and " write " operating efficiency with " wipings ", thus the performance of raising device.

For solving the problems of the technologies described above, the technical scheme of floating gate flash memory device of the present invention is, comprise source electrode and drain electrode, above gap between described source electrode and the drain electrode, be provided with multi-crystal silicon floating bar and control gate, be separated with silicon dioxide layer between described floating boom and described source electrode and the drain electrode, it is characterized in that described floating boom is " recessed " font of the wedge angle of the oriented upper process in two ends, described control gate covers described floating boom fully, is separated with silicon dioxide between described floating boom and the described control gate.

Floating gate flash memory device provided by the invention increases substantially flush memory device and " writes " operating efficiency with " wipings ", thus the performance of raising device.

Description of drawings

The present invention is further detailed explanation below in conjunction with drawings and Examples:

Fig. 1 and Fig. 2 are the structural representation of existing floating gate flash memory device;

Fig. 3 is the structural representation of floating gate flash memory device of the present invention;

Fig. 4 to Figure 10 is for making the schematic diagram of floating boom in the floating gate flash memory device of the present invention.

Reference numeral is among the figure, 1. drain electrode; 2. source electrode; 3. silicon dioxide layer; 4. floating boom; 5. control gate; 51. control gate body part; 52. control gate cover part; 6. silicon dioxide; 7. polysilicon; 8. silicon dioxide layer; 9. silicon nitride; 10. shallow ridges; 11. silicon dioxide.

Embodiment

The structure of floating gate flash memory device of the present invention can be referring to shown in Figure 3, comprise source electrode 2 and drain electrode 1, above described source electrode 2 and the gap between 1 of draining, be provided with multi-crystal silicon floating bar 4 and control gate 5, described floating boom 4 and described source electrode 2 and drain and be separated with silicon dioxide layer 3 between 1, " recessed " font of the wedge angle that described floating boom 4 is the oriented upper process in two ends, described control gate 5 covers described floating boom 4 fully, is separated with silicon dioxide 6 between described floating boom 4 and the described control gate 5.The lower edge of described control gate 5 is flat.

The course of work of floating gate flash memory device structure of the present invention when carrying out " wiping " operation can be referring to shown in Figure 3, and control gate 5 connects high voltage, and source electrode 2 and drain electrode 1 connect high voltage, and electronics passes silicon oxidation isolated area 6 and flows into control gate 5 from the tip of the both sides of floating boom 4." wiping " of the present invention used different silicon dioxide layer 3 with " writing ", in " writing ", use silicon dioxide layer 3, in " wiping ", then used silicon oxidation isolated area 6, therefore make " wiping " and " writing " independently to carry out respectively, improved the operating efficiency of flush memory device greatly.

Floating boom can adopt following method to make in the floating gate flash memory device of the present invention, and concrete steps comprise:

(1) the deposit polysilicon 7, growthing silica layer 8, and the deposit silicon nitride layer 9 afterwards, and as shown in Figure 4, growthing silica layer 8 can adopt the method for thermal oxidation;

(2) do the silicon nitride that removes the floating boom band of position quarter, as shown in Figure 5;

(3) do the silicon dioxide of carving the removal floating boom band of position, and be positioned at the non-perpendicular dried shallow ridges 10 that carves in the floating boom band of position on polysilicon 7, the bottom of described shallow ridges is flat, and sidewall has the gradient, as shown in Figure 6;

(4) deposit silica 11 fills up shallow ridges once more, as shown in Figure 7;

(5) cmp is removed the floating boom position silicon dioxide of (4) step deposit in addition, exposes silicon nitride layer 9 fully, thereby has formed the silicon dioxide 6 that is isolated between described floating boom and the control gate, as shown in Figure 8;

(6) etch away the floating boom band of position silicon nitride layer and the silicon dioxide layer of (1) step deposit in addition, only remaining polysilicon 7 and the silicon dioxide 6 that has shallow ridges, as shown in Figure 9;

(7) be not etched away the polysilicon 7 that the silicon dioxide 6 that obtained by (5) step covers, thereby obtain floating boom 4, as shown in figure 10.

The floating gate flash memory device of producing by said method can increase substantially flush memory device and " write " operating efficiency with " wipings ", thus the performance of raising device.

Claims

1. floating gate flash memory device, comprise source electrode and drain electrode, above gap between described source electrode and the drain electrode, be provided with multi-crystal silicon floating bar and control gate, be separated with silicon dioxide layer between described floating boom and described source electrode and the drain electrode, it is characterized in that, described floating boom is " recessed " font of the wedge angle of the oriented upper process in two ends, and described control gate covers described floating boom fully, is separated with silicon dioxide between described floating boom and the described control gate.

2. floating gate flash memory device according to claim 1 is characterized in that, the lower edge of described control gate is flat.