EP0879480A1 - Read-only memory cell device with insulating trenches and method for the production thereof - Google Patents
Read-only memory cell device with insulating trenches and method for the production thereofInfo
- Publication number
- EP0879480A1 EP0879480A1 EP97914129A EP97914129A EP0879480A1 EP 0879480 A1 EP0879480 A1 EP 0879480A1 EP 97914129 A EP97914129 A EP 97914129A EP 97914129 A EP97914129 A EP 97914129A EP 0879480 A1 EP0879480 A1 EP 0879480A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- source
- memory cell
- drain
- mos transistors
- cell device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B20/00—Read-only memory [ROM] devices
- H10B20/27—ROM only
- H10B20/30—ROM only having the source region and the drain region on the same level, e.g. lateral transistors
- H10B20/38—Doping programmed, e.g. mask ROM
- H10B20/383—Channel doping programmed
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B20/00—Read-only memory [ROM] devices
Definitions
- the invention relates to a fixed value memory cell device and a method for producing a fixed value memory cell device with a substrate consisting of semiconductor material which has memory cells arranged in the form of columns and rows in the area of a main area in a cell field, each memory cell each ⁇ Weil has at least one MOS transistor with a source region, a drain region, a channel region, a gate dielectric and a gate electrode, the MOS transistors of one column being connected in series, each
- Generic fixed value memory cell devices are, for example, from R. Cuppens and LHM Sevat, "A 256 kbit ROM with Serial ROM Cell Structure", IEEE JOURNAL OF SOLID STATE CIRCUITS, VOL. SC-18, No. 3, June 1983, pages 340-344, and from S. Kamuro, et.al., "High Density CMOS Read-Only Memories for a Handheld Electronics Language Translator", IEEE Transactions on Consumer Electronics, Vol. CE-27, No. 4, No ⁇ vember 1981, pages 605 ff.
- a memory cell arrangement with a NAND circuit configuration is used in series to increase the memory density per unit area, in which the formation of contact holes in the memory cell array can be avoided, whereby a very small ROM memory cell can be produced.
- NOR circuit configuration Compared to the read-only memories in a parallel arrangement of the memory cells with NOR circuit configuration, however, a reduced access speed must be accepted.
- the greatest possible storage density is in the foreground in order to be able to accommodate the largest possible number of storage cells per unit area with sufficiently low process costs to achieve a corresponding cost advantage.
- a cell size of 5F 2 can be achieved with conventional CMOS technologies using a serial circuit arrangement of the memory cells in a NAND cell configuration, where F is the smallest that can be produced or used in the respective technology .resolvable structure size means.
- patent applications P 44 34 725 and P 44 37 581 by the same applicant have developed further developed fixed value memory cell devices and methods for their manufacture, in which the memory cell transistors are arranged in a vertical arrangement relative to the main surface of the silicon substrate .
- Such more advanced, but more complex to manufacture, fixed value memory cell devices have a memory density of 2F 2 cells.
- the invention is based on the object of providing a fixed value memory cell device and a method for producing a fixed value memory cell device which, with a high packing density of the memory cells and a high yield, simpler and more cost-effective production offers.
- the source and drain regions of the MOS transistors in a column run substantially parallel to one another at a predetermined distance, are electrically insulated from one another and are made from the semiconductor material of the substrate and are made from the semiconductor material of the substrate are formed which, starting from the main surface of the substrate, have a predetermined web depth, and the word lines for connecting the gate electrodes of the MOS transistors are arranged to run transversely to the longitudinal direction of the source / drain webs.
- An essential feature of the invention therefore consists in providing a memory cell arrangement with crossing source / drain and gate paths with the possibility of a cell size of IF 2 instead of the previously possible maximum memory density of 2F 2 , so that it is precise one memory cell per base area F 2 can be realized.
- the drain region of a MOS transistor of a column formed in the main surface of a source / drain web simultaneously represents the source region of the MOS transistor of the same column immediately adjacent on the source / drain web.
- the memory cells can be configured in a so-called NAND circuit configuration, which enables a particularly large memory density with a cell structure that is technologically simple to produce.
- the ratio of the web width b measured on the main surface transversely to the longitudinal direction of the web to the spacing a of the source / drain webs is approximately 20% to 40%, in particular approximately one third, of the structure size F which can be resolved.
- the web width b of the source / drain web is preferably approximately 0.3 ⁇ m with a spacing a of the source / drain webs corresponding to dissolvable structure size F, so also approximately 1 ⁇ m.
- Memory cell density of exactly one memory cell per base area F 2 According to the design of the fixed value memory cell device according to the invention with series-connected memory transistors in a NAND cell configuration, it is provided that each of the MOS transistors of a memory cell formed on the main surface of the source / drain webs is programmed as a transistor of the depletion type or enhancement type is.
- OTP memory one-time programmable memory
- mask-programmable ROM read-only memory
- the space between the source / drain bars is filled with an electrically insulating material, in particular a material containing SiO 2 .
- both the manufacture of the source / drain lands having a predetermined land width b and the manufacture or adjustment of the source running in the main surface along the longitudinal direction of the source / drain lands are carried out and drain regions each by means of a self-adjusting method step by means of spacers, so-called spacers, which are then used as a “hard” mask for structuring the layers underneath.
- spacers so-called spacers
- spacers By using two successive spacer techniques in parallel directions orthogonally to one another for the main surface of the substrate, it is possible to form a periodic arrangement of the memory cells with the smallest resolvable structure size F with exactly one memory cell per base area F 2 .
- Each self-adjusting process step can have the following sub-steps:
- the structured masking layer can be used as an etching mask in the self-adjusting method step for producing the source / drain webs to be carried out initially, while the structured masking layer can be used as an implant in the self-adjusting method step for manufacturing the source and drain regions which is subsequently to be carried out ⁇ on mask can be used.
- Cell array of the memory cell device simultaneously form MOS transistors for driving the memory cell device on the periphery on the substrate.
- the gate oxide and the gate electrodes of the MOS transistors in the periphery can be formed in the same process steps as the gate oxide and the gate electrodes in the cell field.
- Figure 1 is a schematic sectional view of a p-
- Solid-state memory cell device designed according to an embodiment of the invention after depositing a SiO 2 and Si 3 N 4 layer serving as a masking layer,
- FIG. 2 shows a schematic sectional view of the wafer after deposition and structuring of a CVD-SiO 2 layer serving as an auxiliary layer
- FIG. 3 shows a schematic sectional view of the wafer after depositing a poly-Si layer, from which the spacers are formed
- FIG. 4 shows a schematic sectional view of the wafer after anisotropic etching of the poly-Si layer
- FIG. 5 shows a schematic sectional view of the wafer after removal of the remaining auxiliary SiO 2 layer
- Figure 6 is a schematic sectional view of the wafer according to
- Figure 7 is a schematic sectional view of the wafer according to
- FIG. 8 shows a schematic sectional view of the wafer after conformal deposition and filling of a TE0S-Si0 2 layer
- FIG. 9 shows a schematic sectional view of the wafer after etching back the TEOS-Si0 2 layer
- FIG. 10 shows a schematic sectional view of the wafer taken along line XX in FIG. 9, to explain the programming of the individual memory cells by means of lacquer-masked ion implantation
- FIG. 11 shows a schematic sectional view of the wafer after deposition and structuring of a TEOS layer
- FIG. 12 shows a schematic sectional view of the wafer after depositing an SiO 2 / gate oxide
- FIG. 13 shows a schematic sectional view of the wafer after deposition of a poly-Si layer, doping, and healing;
- FIG. 14 shows a schematic sectional view of the wafer after anisotropic etching back of the poly-Si layer
- FIG. 15 shows a schematic sectional view of the wafer after removal of the oxide layers
- FIG. 16 shows a schematic sectional view of the wafer after an ion implantation has been carried out to form the source / drain regions
- FIG. 17 shows a schematic view of a read-only memory cell device according to an exemplary embodiment of the invention.
- Figure 18 is a schematic plan view of the fixed value memory cell device.
- a thin SiO 2 layer 3 and then an Si 3 N 4 layer 4 with a respective thickness of approximately 100 nm to 200 nm are grown or coated over the entire area deposited.
- a CVD-SiO 2 layer 5 serving as an auxiliary layer is deposited over the entire surface with a thickness of approximately 300 nm to 400 nm and structured according to FIG. 2 by means of conventional photolithographic methods.
- a poly-Si layer 6 with a thickness of about 300 nm is then deposited over the entire area and then anisotropically etched back, so that the arrangement shown in FIG. 4 results.
- the structured CVD-SiO 2 layer 5 is then removed isotropically, preferably by means of a chemical etchant such as, in particular, hydrofluoric acid, the polysilicon spacers 7 being left as they are in a subsequent process step according to FIG. 5 as "hard” Mask for structuring the underlying Si 3 N 4 layer 4.
- a chemical etchant such as, in particular, hydrofluoric acid
- the polysilicon spacers 7 being left as they are in a subsequent process step according to FIG. 5 as "hard” Mask for structuring the underlying Si 3 N 4 layer 4.
- the poly-Si spacers 7 are removed and the Si 3 N 4 structure preferably by means of an anisotropic etchant transfer the Si0 2 layer 3 (see FIG. 6)
- the composite consisting of the structured Si0 2 and Si 3 N 4 layers 3, 4 then serves as a “hard” mask for further structuring of the silicon substrate 2 in accordance with FIG. 6
- Source / drain webs 8 which are electrically insulated from one another and run parallel to one another at a predetermined distance a and have a depth t of approximately 400 nm starting from the main surface 1 of the substrate 2.
- the ratio of web width b to the distance a between the source / drain webs 8 is approximately one third.
- the entire arrangement according to FIG. 8 is filled with a conformally deposited TEOS-SiO 2 layer 9, which has a thickness of about 600 nm to 800 nm, and then etched back according to FIG. 9 or by a “Chemical Mechanical Polishing "Process step ground back.
- the threshold voltage of the memory cell transistors T and, if appropriate, of the planar transistors (not shown in the peripheral area) which are outside the cell field are then defined via an implantation step.
- a suitable implantation mask 10 for example in the form of a photoresist, is applied and structured on the main surface 1, and the transistors are set by means of a suitable dose selection according to the implantation indicated by arrows 11.
- the opening 12 of the resist mask 10 should be F • F in order to be able to intercept the adjustment tolerances in the subsequent photolithography steps.
- the implantation can be carried out, for example, with boron, the implantation energy being, for example, about 25 keV and the dose being, for example, 1 * 10 cm " .
- the gate electrodes are manufactured in a manner similar to the manufacture of the source / drain webs by means of a further self-adjusting method step. According to FIG. 11, TE0S-Si0 2 -
- Layer 13 deposited and structured. This is followed by gate oxide deposition in the case of a mask-programmed read-only memory or, as in the case of a once electrically programmable read-only memory, ONO formation.
- a thermal oxidation at, for example, 750 ° is carried out after removing the implantation mask.
- a thin gate oxide 14 with a scalable thickness of approximately 5 nm to 10 nm is formed on exposed silicon surfaces, so that the arrangement shown in FIG. 12 results.
- a poly-Si layer 15 is deposited according to FIG. 13, optionally doped and healed by ion implantation or coating, and then anisotropically etched back according to FIG. According to FIG.
- the oxide layers 13 and 14 are removed dry so that spacers 16 remain which are used as a “hard” mask for ion implantation for the formation of the source / drain regions 17.
- the source / dram regions 17 are formed by implantation with, for example, arsenic at an energy of 50 keV with a dose of 5 ⁇ 10 15 cm "3 Peripherals can be produced without any additional mask, and further process steps known from MOS technology, such as setting an LDD profile, salicide technology and the like, can be carried out for the production of all lateral MOS transistors in the cell field and in the periphery area
- word lines 18 for the connection of the gate electrodes of the MOS transistors T are arranged to run transversely to the longitudinal direction of the source / drain bars 8 by means of a conventional metallization step Representation of an embodiment of the arrangement realized in this way.
- FIG. 18 shows a schematic top view of the arrangement corresponding to the state according to FIG. 3, with the reference numerals Y and Y 'the position of the contact holes 19 and 20 for the connection of bit lines, and the course of a using the dash-dotted line 21 Cell field is indicated.
- the contact holes again have dimensions of F • F.
Landscapes
- Semiconductor Memories (AREA)
- Non-Volatile Memory (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19604260A DE19604260C2 (en) | 1996-02-06 | 1996-02-06 | Fixed value memory cell device and a method for the production thereof |
DE19604260 | 1996-02-06 | ||
PCT/DE1997/000239 WO1997029516A1 (en) | 1996-02-06 | 1997-02-06 | Read-only memory cell device with insulating trenches and method for the production thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0879480A1 true EP0879480A1 (en) | 1998-11-25 |
Family
ID=7784654
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97914129A Withdrawn EP0879480A1 (en) | 1996-02-06 | 1997-02-06 | Read-only memory cell device with insulating trenches and method for the production thereof |
Country Status (6)
Country | Link |
---|---|
US (1) | US6211019B1 (en) |
EP (1) | EP0879480A1 (en) |
JP (1) | JP3636475B2 (en) |
KR (1) | KR100466349B1 (en) |
DE (1) | DE19604260C2 (en) |
WO (1) | WO1997029516A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0967654A1 (en) * | 1998-06-26 | 1999-12-29 | EM Microelectronic-Marin SA | Non-volatile semiconductor memory device |
DE19957117A1 (en) * | 1999-11-26 | 2001-06-07 | Infineon Technologies Ag | Mask programmable ROM memory device and method of manufacturing the same |
DE10258194B4 (en) * | 2002-12-12 | 2005-11-03 | Infineon Technologies Ag | Semiconductor memory with charge-trapping memory cells and manufacturing process |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4151020A (en) * | 1977-01-26 | 1979-04-24 | Texas Instruments Incorporated | High density N-channel silicon gate read only memory |
US4905062A (en) * | 1987-11-19 | 1990-02-27 | Texas Instruments Incorporated | Planar famos transistor with trench isolation |
JPH01235269A (en) * | 1988-03-15 | 1989-09-20 | Fujitsu Ltd | Semiconductor device |
KR970000533B1 (en) * | 1990-12-20 | 1997-01-13 | 후지쓰 가부시끼가이샤 | Eprom with trench in thick field oxide |
JPH05259410A (en) * | 1992-03-13 | 1993-10-08 | Toshiba Corp | Mask rom |
US5308777A (en) * | 1993-07-28 | 1994-05-03 | United Microelectronics Corporation | Mask ROM process |
JPH07263677A (en) * | 1994-03-18 | 1995-10-13 | Mitsubishi Electric Corp | Semiconductor device and its manufacture |
US5397727A (en) * | 1994-07-20 | 1995-03-14 | Micron Technology, Inc. | Method of forming a floating gate programmable read only memory cell transistor |
DE4434725C1 (en) * | 1994-09-28 | 1996-05-30 | Siemens Ag | Fixed value memory cell arrangement and method for the production thereof |
DE4437581C2 (en) * | 1994-10-20 | 1996-08-08 | Siemens Ag | Method for producing a read-only memory cell arrangement with vertical MOS transistors |
DE19514834C1 (en) * | 1995-04-21 | 1997-01-09 | Siemens Ag | Read-only memory cell arrangement and method for its production |
DE19549486C2 (en) * | 1995-11-28 | 2001-07-05 | Siemens Ag | Fixed value memory cell arrangement and method for the production thereof |
-
1996
- 1996-02-06 DE DE19604260A patent/DE19604260C2/en not_active Expired - Fee Related
-
1997
- 1997-02-06 JP JP52805597A patent/JP3636475B2/en not_active Expired - Fee Related
- 1997-02-06 EP EP97914129A patent/EP0879480A1/en not_active Withdrawn
- 1997-02-06 KR KR10-1998-0705995A patent/KR100466349B1/en not_active IP Right Cessation
- 1997-02-06 WO PCT/DE1997/000239 patent/WO1997029516A1/en active IP Right Grant
-
1998
- 1998-08-06 US US09/130,051 patent/US6211019B1/en not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
See references of WO9729516A1 * |
Also Published As
Publication number | Publication date |
---|---|
KR19990082266A (en) | 1999-11-25 |
DE19604260C2 (en) | 1998-04-30 |
JP3636475B2 (en) | 2005-04-06 |
DE19604260A1 (en) | 1997-08-07 |
US6211019B1 (en) | 2001-04-03 |
KR100466349B1 (en) | 2005-05-16 |
WO1997029516A1 (en) | 1997-08-14 |
JP2000504880A (en) | 2000-04-18 |
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