US20110095351A1 - Semiconductor devices and methods of fabricating the same - Google Patents
Semiconductor devices and methods of fabricating the same Download PDFInfo
- Publication number
- US20110095351A1 US20110095351A1 US12/980,399 US98039910A US2011095351A1 US 20110095351 A1 US20110095351 A1 US 20110095351A1 US 98039910 A US98039910 A US 98039910A US 2011095351 A1 US2011095351 A1 US 2011095351A1
- Authority
- US
- United States
- Prior art keywords
- active region
- selection gate
- insulating layer
- layer
- line
- 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.)
- Abandoned
Links
- 239000004065 semiconductor Substances 0.000 title abstract description 30
- 238000000034 method Methods 0.000 title description 15
- 230000000903 blocking effect Effects 0.000 claims description 9
- 239000007769 metal material Substances 0.000 claims description 5
- 238000002955 isolation Methods 0.000 abstract description 60
- 239000000758 substrate Substances 0.000 abstract description 10
- 239000010410 layer Substances 0.000 description 146
- 238000005530 etching Methods 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 11
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- 230000004888 barrier function Effects 0.000 description 5
- 229910052721 tungsten Inorganic materials 0.000 description 4
- 239000010937 tungsten Substances 0.000 description 4
- 230000006870 function Effects 0.000 description 3
- 239000002356 single layer Substances 0.000 description 2
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- -1 tungsten nitride Chemical class 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
- H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
- H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
- H01L21/822—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being a semiconductor, using silicon technology
- H01L21/8232—Field-effect technology
- H01L21/8234—MIS technology, i.e. integration processes of field effect transistors of the conductor-insulator-semiconductor type
- H01L21/823481—MIS technology, i.e. integration processes of field effect transistors of the conductor-insulator-semiconductor type isolation region manufacturing related aspects, e.g. to avoid interaction of isolation region with adjacent structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
- H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
- H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
- H01L21/822—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being a semiconductor, using silicon technology
- H01L21/8232—Field-effect technology
- H01L21/8234—MIS technology, i.e. integration processes of field effect transistors of the conductor-insulator-semiconductor type
- H01L21/823437—MIS technology, i.e. integration processes of field effect transistors of the conductor-insulator-semiconductor type with a particular manufacturing method of the gate conductors, e.g. particular materials, shapes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
- H01L29/423—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
- H01L29/42312—Gate electrodes for field effect devices
- H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42356—Disposition, e.g. buried gate electrode
- H01L29/4236—Disposition, e.g. buried gate electrode within a trench, e.g. trench gate electrode, groove gate electrode
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B41/00—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates
- H10B41/30—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by the memory core region
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B41/00—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates
- H10B41/30—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by the memory core region
- H10B41/35—Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates characterised by the memory core region with a cell select transistor, e.g. NAND
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B69/00—Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices
Definitions
- the present invention disclosed herein relates to semiconductor devices and methods of fabricating the same. More particularly, the invention relates to semiconductor devices having a transistor with an extended channel width and methods of fabricating the same.
- a memory device for storing information may include a cell array with patterns having minimum line-widths.
- an active region and a device isolation region may be formed such that they have minimum line-widths corresponding to a gate pattern of a transistor.
- a sufficient channel length should be provided in order to suppress and/or prevent short channel effect and leakage current.
- a structure in which an effective channel length of the transistor is increased by, e.g., etching a portion of the active region to form a recess region has been developed. In such cases, the channel length may be secured without increasing a gate line-width by forming the channel of the transistor in the recess region.
- the recess region may be filled with a gate insulating layer, and/or it may be difficult to secure an effective channel width because the channel is formed in a portion of the recess region.
- a driving current may be decreased and a gate controllability of the transistor may be lowered, which may negatively impact leakage current and threshold voltage characteristics.
- Flash memory devices may employ a method of forming a channel of a selection transistor in a recess region in order to suppress and/or prevent gate-induced drain leakage (GIDL) and punchthrough, and to avoid program/erase errors of an outermost cell transistor of a cell string.
- GIDL gate-induced drain leakage
- the gate insulating layer may completely fill the recess region. Thus, gate controllability of the transistor may be degraded, which may cause the transistor to operate abnormally.
- the present invention is therefore directed to semiconductor devices and methods of manufacturing thereof, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.
- At least one of the above another features and advantages of the present invention may be realized by providing a semiconductor device including a device isolation layer disposed in a semiconductor substrate, an active region defined by the device isolation layer, the active region including a main surface and a recess region including a bottom surface that is lower than the main surface, and a gate electrode formed over the recess region, wherein a top surface of the device isolation layer adjacent to the recess region is lower than the bottom surface of the recess region.
- the device isolation layer adjacent to the recess region may be recessed below a portion adjacent to the main surface of the active region. At least a portion of the active region may protrude higher than the device isolation layer. A top surface of the device isolation layer adjacent to the main surface of the active region may be lower than the main surface of the active region.
- the active region may extend in a row direction, and the active region protrudes higher than the device isolation layer extending adjacent to the active region along the column direction.
- a flash memory device including a device isolation layer in a semiconductor substrate, an active region defined by the device isolation layer, the active region including a main surface and a recess region of which a bottom surface is lower than the main surface, a word line crossing over the main surface of the active region, and a selection gate line disposed in parallel with the word line, and crossing over the recess region, wherein a top surface of the device isolation layer adjacent to the recess region is lower than the bottom surface of the recess region.
- the method may further include a pair of recess regions disposed in the active region, and separated from each other by a predetermined distance, a ground selection gate line and a string selection gate line crossing over the respective recess regions, and a plurality of word lines crossing over the main surface of the active region between the ground selection gate line and the string selection gate line.
- a charge trapping layer may be interposed between the word line and the active region, and between the selection gate line and the active region.
- a charge trapping layer may be interposed between the word line and the active region, and a gate insulating layer may be interposed between the selection gate line and the active region.
- the device may further include a tunnel insulating layer, a charge trapping layer and a blocking insulating layer, which may be sequentially stacked between the word line and the active region, wherein the word line disposed over the blocking insulating layer may include a metallic material having a work function of about 4.5 eV or greater.
- the word line may include a floating gate on the active region, a control gate electrode formed on the floating gate, and crossing over the active region, and an intergate dielectric layer interposed between the floating gate and the control gate electrode, wherein a tunnel insulating layer may be interposed between the floating gate and the active region.
- the selection gate line may include a lower selection gate, an upper selection gate on the lower selection gate, and an intergate insulating layer interposed between the lower selection gate and the upper selection gate, the gate insulating layer may be interposed between the lower selection gate and the active region, and the lower selection gate and the upper selection gate being electrically connected to each other.
- a width of the selection gate line may be greater than that of the recess region.
- the selection gate line may cover the active region at either side of the recess region.
- At least one of the above another features and advantages of the present invention may be separately realized by providing a method for fabricating a semiconductor device, the method including forming a device isolation layer in a semiconductor substrate to define an active region having a main surface extending in a column direction, forming a hard mask having an opening exposing a portion of the active region, etching a portion of the active region using the hard mask as an etch mask to form a recess region, and etching the device isolation layer adjacent to the recess region such that a top surface of the device isolation layer may be lower than a bottom surface of the recess region.
- the opening may be formed such that it extends in a row direction and exposes the active region and the device isolation layer, and the device isolation layer may be etched using the hard mask as an etch mask.
- Etching of the device isolation layer may be performed before or after the forming of the recess region.
- the method may further include etching the device isolation layer by etch-back process to make the device isolation layer lower than the main surface of the active region, and forming the recess region of which a bottom surface is higher than a top surface of the recessed device isolation layer. Etching of the device isolation layer by etch-back process may be performed before or after the forming of the recess region.
- the method may further include forming a word line crossing over the main surface of the active region, and a selection gate line crossing over the recess region.
- FIGS. 1A and 1B illustrate cross-sectional views of a semiconductor device according to a first exemplary embodiment of the present invention, respectively taken along a first and a second direction that is perpendicular to the first direction;
- FIGS. 2A through 6A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a first exemplary embodiment of the present invention, taken along the first direction;
- FIGS. 2B through 6B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the first exemplary embodiment of the present invention, taken along the second direction;
- FIGS. 7A and 8A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a second exemplary embodiment of the present invention, taken along the first direction;
- FIGS. 7B and 8B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the second exemplary embodiment of the present invention, taken along the second direction.
- FIGS. 1A and 1B illustrate cross-sectional views of a semiconductor device according to a first exemplary embodiment of the present invention, respectively taken along a first and a second direction that is perpendicular to the first direction.
- a device isolation pattern 52 a may be formed in a semiconductor substrate 50 to define an active region 54 .
- a main surface region 54 a of the active region 54 defined, e.g., by two adjacent device isolation patterns 52 a , may extend along the first direction, e.g., a column direction, and recess region(s) 60 may be formed in a predetermined region of the active region 54 .
- the recess region 60 may correspond to a region where a gate electrode of a selection transistor is formed.
- a ground selection line GSL and a string selection line SSL may cross over the active region 54 , may extend parallel to each other, and may be separated from each other by a predetermined distance.
- a plurality of word lines WLn may be parallel to and disposed between the ground selection line GSL and the string selection line SSL.
- the active regions 54 under the ground selection line GSL and the string selection line SSL may correspond to the recess regions 60 .
- the recess regions 60 may include a bottom surface 60 a that may be lower than the main surface 54 a of the active region 54 .
- a width of the recess region 60 may be smaller than a width of the string and/or ground selection lines SSL and GSL.
- the string selection line SSL and the ground selection line GSL may overlap the active region 54 beyond the recess region 60 .
- an upper surface 52 b of the device isolation pattern 52 a disposed adjacent to the recess region 60 may be lower than the bottom surface 60 a of the recess region 60 .
- the active region 54 may include a protruding upper portion 54 t that protrudes upward beyond the upper surface 52 b of the device isolation pattern 52 a .
- the main surface 54 a of the active region 54 when observing a cross-sectional of the selection transistors taken along a direction parallel to the ground or string selection line GSL or SSL, the main surface 54 a of the active region 54 , corresponding to the protruding upper portion 54 t , may have a rounded, sloped or curved shape.
- the protruded upper portion 54 t of the active region 54 may have a hemispherical-like, trapezoidal-like, or cone-like cross-sectional shape as a result of etching conditions.
- the word line WLn may include a cell gate electrode 68 and a cell gate insulating layer 62 .
- the cell gate insulating layer 62 may be interposed between the semiconductor substrate 50 and the cell gate electrode 68 .
- the cell gate insulating layer 62 may be configured with a tunnel insulating layer 62 a , a charge trapping layer 62 b , and a blocking insulating layer 62 c , which may be stacked in sequence.
- the ground and string selection lines GSL and SSL may have the same stack structure as the word line WLn.
- the ground and string selection lines GSL and SSL may include a selection gate electrode 68 and a selection gate insulating layer interposed between the semiconductor substrate 50 and the selection gate electrode 68 .
- the selection gate insulating layer may have the same stack structure as the cell gate insulating layer 62 . That is, the selection gate insulating layer may be configured with a tunnel insulating layer 62 a , a charge trapping layer 62 b , and a blocking insulating layer 62 c . In other embodiments of the invention, e.g., the selection gate insulating layer may be configured with a monolayer as a gate insulating layer.
- a channel region of a memory cell transistor may be formed in the active region 54 under the word line WLn.
- a channel region of the ground selection line GSL may be formed in the active region 54 under the ground selection line GSL, and a channel region of the string selection line SSL may be formed in the active region 54 under the string selection line SSL.
- the channel regions of the ground and string selection lines GSL and SSL may be formed in the recess regions 60 so that they may have a larger effective channel length than the widths of the ground and string selection lines GSL and SSL.
- the channel regions of the ground and string selection lines GSL and SSL may be formed along the protruding upper portion 54 t of the active region 54 .
- an effective channel width may be increased, and may be greater than the width of the active region 54 .
- the gate insulating layers of the ground and string selection lines GSL and SSL may be formed such that they cover the protruding upper portion 54 t of the active region 54 .
- the gate insulating layers of the ground and string selection lines GSL and SSL may be formed such that they surround sidewalls of the protruded upper portion 54 t as well as the main surface 54 a of the active region can 54 .
- the main surface 54 a and portions of the sidewalls of the protruding upper portion 54 t may be correspond to the channel region.
- the gate insulating layer may fill the recess region.
- controllability of a gate of the transistor may be hindered.
- the recess region 60 may be formed so as to ensure that the recess region 60 may not be completely filled with the gate insulating layer. More particularly, in some embodiments of the invention, by providing the protruding upper portion 54 t of the active region 54 , respective portions of the protruding upper portion 54 t may be used as the channel region of the transistor.
- the blocking insulating layer 62 c may have a higher dielectric constant than a dielectric constant of the tunnel insulating layer 62 a .
- the cell gate electrode 68 may include a metallic material having a work function greater than about 4.5 eV, wherein the metallic material may be in contact with the blocking insulating layer 62 c .
- the cell gate electrode 68 may include a barrier metal layer 64 , e.g., a tantalum nitride layer, with a metal layer 66 having excellent conductivity, e.g., a tungsten and/or a tungsten nitride layer, formed on the barrier metal layer 64 .
- FIGS. 2B and 6B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the first exemplary embodiment of the present invention, taken along the second direction.
- a device isolation layer 52 may be formed in a semiconductor substrate 50 .
- the device isolation layer 52 may define the active region 54 .
- the device isolation layer 54 may be formed using a shallow trench isolation (STI) technique.
- STI shallow trench isolation
- the main surface 54 a of the active region 54 may extend along the first direction, e.g., a column direction.
- the active regions 54 may be disposed to extend along the first direction, i.e., substantially perpendicular to the first direction along which the gate and/or string selection lines GSL, SSL may extend.
- a hard mask 56 may be formed on the resultant structure.
- the hard mask 56 may have an opening 58 exposing a portion of the active region 54 .
- the opening 58 may extend in the second direction intersecting the active regions 54 and may expose the device isolation layer 52 defining the active regions 54 as well as the active regions 54 .
- the opening 58 may be placed over a region where a channel of the selection transistor will be formed in the NAND type cell array, and may have a smaller width W 1 than that of the gate line of the select transistor.
- the active region 54 may be etched to form the recess region 60 using the hard mask 56 as an etch mask.
- the bottom surface 60 a of the recess region 60 may be positioned lower than the main surface 54 a of the active region. Therefore, the device isolation layer 52 adjacent to the recess region 60 may include a protrusion 52 t that may be higher than the bottom surface 60 a of the recess region 60 .
- the device isolation layer 52 may then be etched using the hard mask 56 as an etch mask.
- the hard mask 56 may be etched using a different etching solution than that used to etch the active region 54 .
- the protrusions 52 t of the device isolation layer 52 adjacent to the recess region 60 may be etched such the device isolation pattern 52 b may be formed.
- the upper surface 52 a of the device isolation pattern 52 a may be lower than the bottom surface 60 a of the recess region 60 .
- the active region 54 may include protruded upper portion(s) 54 t , which may be higher than the upper surface 52 b of the device isolation pattern 52 a .
- the protruded upper portion 54 t of the active region 54 may have a hemispherical-like, trapezoidal-like, or cone-like cross-sectional shape as a result of the etching conditions.
- the active region 54 may include the recess region 60 having the bottom surface 60 a that may be lower than the main surface 54 a of the active region 54 , and the device isolation pattern 52 a adjacent to the recess region 60 may be lower than the bottom surface 60 a of the recess region 60 , sidewalls of the active region 54 may be exposed at a region higher than the device isolation pattern 52 s . More particularly, sidewalls of the active region 54 may be exposed at a region higher than the upper surface 52 a of the device isolation pattern 52 b.
- the device isolation layer 52 may be etched using the hard mask 56 as an etch mask and thus, only the device isolation layer 52 adjacent to the recess region 60 may be etched, i.e., shortened to become lower than the active region 54 .
- the device isolation layer 52 may be etched over an entire surface of the cell array region by an etch-back process after removing the hard mask layer 56 , whereby the device isolation layer 52 adjacent to the main surface of the active region 54 may be lower than the active region 54 .
- the device isolation layer 52 may be etched to be lower than the bottom surface 60 a of the recess region 60
- the upper surface 52 b of the device isolation pattern 52 a adjacent to the recess region 60 may be lower than the bottom surface 60 a of the recess region 60 .
- the device isolation layer 52 at a level lower than the recess region 60 by etching the device isolation layer 52 before forming the recess region 60 . That is, after etching the device isolation layer 52 using the hard mask 56 as an etch mask, the active region 54 may be etched using the hard mask 56 as an etch mask. Before forming the hard mask 56 , the device isolation layer 52 may be etched in the cell array so that the upper surface 52 b of the device isolation layer 52 becomes lower than the main surface 54 a of the active region 54 . Thereafter, the hard mask 56 may be formed, and the recess region 60 may then be formed using the hard mask 56 .
- the active region 54 may have a protrusion that is higher than the device isolation layer 52 . That is, the active region 54 may have a sidewall or portion extending from the main surface 54 a thereof that is higher than, i.e., protruding, relative to the upper surface 52 b of the device isolation pattern 52 a .
- the channel width of the cell transistor can be increased because the channel of the cell transistor can be formed on the main surface 54 a and/or protruding sidewall of the active region 54 .
- the hard mask 56 may be removed and the gate insulating layer 62 may then formed on a surface, e.g., an entire surface, of the active region 54 .
- the gate insulating layer 62 may have a multi-stacked structure including a charge trapping layer.
- the gate insulating layer 62 may include the tunnel insulating layer 62 a , the charge trapping layer 62 b and the blocking insulating layer 62 c.
- the gate electrode layer 68 may then be formed on the gate insulating layer 62 .
- the gate electrode layer 68 may include the barrier metal layer 64 formed of a metallic material having a work function of about 4.5 eV or greater.
- the barrier metal layer 64 may include tantalum nitride.
- the metal layer 66 with excellent conductivity may then be formed on the barrier metal layer 64 .
- the metal layer 66 may be formed of tungsten and/or tungsten nitride layer.
- at least the gate electrode layer 68 may be patterned to form a plurality of word lines WLn crossing over the active region 54 , and ground and string section lines GSL and SSL crossing over the recess region 60 .
- the gate insulating layer 62 may be conformally formed along a surface profile of the recess region 60 .
- the recess region 60 was filled with the gate insulating layer.
- the recess region 60 may include the bottom surface 60 a that is higher than the upper surface 52 b of the device isolation pattern 52 a , the recess region 60 may not be filled with the gate insulating layer 62 .
- embodiments of the invention may be advantageous over conventional devices at least because embodiments of the invention provide the active region 54 and the recess region 60 such that the recess region 60 may not be completely filled with a gate insulating layer formed thereon.
- the gate insulating layer 62 may be formed so as to encompass the bottom surface 60 a of the recess region 60 , and thus a contact area between the active region 54 and the gate insulating layer 62 may be enlarged. Therefore, it is possible to increase the channel width of the selection transistor defined in the active region under the ground and string selection lines GSL and SSL.
- the gate insulating layer 62 is illustrated as having a multi-stacked structure all over the active region.
- the gate insulating layer 62 may have a multi-stacked structure in a region where the word lines are formed, but may have a monolayer structure in a region where the ground and string selection lines GSL and SSL are formed.
- the multi-layered gate insulating layer 62 may be partially removed to form a monolayered gate insulating layer.
- FIGS. 7A and 8A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a second exemplary embodiment of the present invention, taken along the first direction.
- FIGS. 7B and 8B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the second exemplary embodiment of the present invention, taken along the second direction.
- a floating gate type flash memory device may include a floating gate.
- the recess region 60 may be formed in the active region 54 , and at least the device isolation pattern 52 a adjacent to the recess region 60 may be etched to have a top surface thereof lower than the bottom surface 60 a of the recess region 60 .
- a gate insulating layer 162 may be formed on the active region 54 , and a floating gate layer 164 , an intergate dielectric layer 166 , and a control gate electrode layer 168 may be formed on the gate insulating layer 162 .
- the intergate dielectric layer 166 may be formed such that it has an opening OX over the recess region 60 , so that the floating gate layer 164 and the control gate electrode layer 168 may be connected to each other.
- the gate insulating layer 162 may be a thin tunnel insulating layer at a portion where the cell transistor will be formed, whereas it may be thicker than the tunnel insulating layer at a portion where the selection transistor will be formed.
- control gate electrode layer 168 , the intergate dielectric layer 166 and the floating gate layer 164 may be sequentially patterned to form word lines WLn crossing over the active region 54 and the ground and selection lines GSL and SSL crossing over the recess region 60 .
- the word line WLn may have a multi-stacked structure in which the floating gate layer 164 , the intergate dielectric layer 166 and the control gate layer 168 are stacked over the tunnel insulating layer 162 in sequence.
- Each of the ground and string selection lines GSL and SSL may include a lower selection gate corresponding to the floating gate 164 , an intergate insulating layer corresponding to the intergate dielectric layer 166 , and an upper selection gate corresponding to the control gate electrode 168 .
- Embodiments of the present invention enable an effective channel width as well as an effective channel length of a transistor, including a channel formed in the recess region, to be secured.
- a selection transistor having a larger effective channel length than a gate linewidth.
- embodiments of the invention enable suppression and/or prevention of degradation of gate controllability for the channel while securing the effective channel width as well.
- a channel width of the cell transistor can be increased.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Engineering (AREA)
- Non-Volatile Memory (AREA)
- Semiconductor Memories (AREA)
Abstract
A semiconductor device includes a device isolation layer in a semiconductor substrate, an active region defined by the device isolation layer, the active region including a main surface and a recess region including a bottom surface that is lower than the main surface, and a gate electrode formed over the recess region, wherein a top surface of the device isolation layer adjacent to the recess region is lower than the bottom surface of the recess region.
Description
- This is a continuation application based on pending application Ser. No. 11/709,814, filed Feb. 23, 2007, the entire contents of which is hereby incorporated by reference.
- 1. Field of the Invention
- The present invention disclosed herein relates to semiconductor devices and methods of fabricating the same. More particularly, the invention relates to semiconductor devices having a transistor with an extended channel width and methods of fabricating the same.
- 2. Description of the Related Art
- As semiconductor memory devices are becoming smaller and/or more highly-integrated, a channel length and width of transistors included therein are becoming smaller. A line-width of an active region corresponding to the channel width of the transistor is also being reduced.
- In general, a memory device for storing information may include a cell array with patterns having minimum line-widths. In a cell array region of the memory device, an active region and a device isolation region may be formed such that they have minimum line-widths corresponding to a gate pattern of a transistor.
- However, as line-width(s) of the gate pattern(s) are reduced, a sufficient channel length should be provided in order to suppress and/or prevent short channel effect and leakage current. A structure in which an effective channel length of the transistor is increased by, e.g., etching a portion of the active region to form a recess region has been developed. In such cases, the channel length may be secured without increasing a gate line-width by forming the channel of the transistor in the recess region.
- However, in such cases, problems may occur, e.g., the recess region may be filled with a gate insulating layer, and/or it may be difficult to secure an effective channel width because the channel is formed in a portion of the recess region. When the effective channel length is not sufficiently secured, a driving current may be decreased and a gate controllability of the transistor may be lowered, which may negatively impact leakage current and threshold voltage characteristics.
- Flash memory devices may employ a method of forming a channel of a selection transistor in a recess region in order to suppress and/or prevent gate-induced drain leakage (GIDL) and punchthrough, and to avoid program/erase errors of an outermost cell transistor of a cell string. However, if minimum line-widths are reduced in order to provide highly-integrated devices, e.g., to about or less than about two times a thickness of a gate insulating layer, the gate insulating layer may completely fill the recess region. Thus, gate controllability of the transistor may be degraded, which may cause the transistor to operate abnormally.
- The present invention is therefore directed to semiconductor devices and methods of manufacturing thereof, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.
- It is therefore a feature of an embodiment of the present invention to provide a semiconductor device that can secure a sufficient effective channel width.
- It is therefore a separate feature of an embodiment of the present invention to provide a method of manufacturing a semiconductor device that can secure a sufficient effective channel width.
- It is therefore a separate feature of an embodiment of the present invention to provide a semiconductor device that can secure an effective channel length and an effective channel line-width.
- It is therefore a separate feature of an embodiment of the present invention to provide a method of manufacturing a semiconductor device that can secure a sufficient effective channel width and an effective line-width.
- At least one of the above another features and advantages of the present invention may be realized by providing a semiconductor device including a device isolation layer disposed in a semiconductor substrate, an active region defined by the device isolation layer, the active region including a main surface and a recess region including a bottom surface that is lower than the main surface, and a gate electrode formed over the recess region, wherein a top surface of the device isolation layer adjacent to the recess region is lower than the bottom surface of the recess region.
- The device isolation layer adjacent to the recess region may be recessed below a portion adjacent to the main surface of the active region. At least a portion of the active region may protrude higher than the device isolation layer. A top surface of the device isolation layer adjacent to the main surface of the active region may be lower than the main surface of the active region. The active region may extend in a row direction, and the active region protrudes higher than the device isolation layer extending adjacent to the active region along the column direction.
- At least one of the above another features and advantages of the present invention may be separately realized by providing a flash memory device including a device isolation layer in a semiconductor substrate, an active region defined by the device isolation layer, the active region including a main surface and a recess region of which a bottom surface is lower than the main surface, a word line crossing over the main surface of the active region, and a selection gate line disposed in parallel with the word line, and crossing over the recess region, wherein a top surface of the device isolation layer adjacent to the recess region is lower than the bottom surface of the recess region.
- The method may further include a pair of recess regions disposed in the active region, and separated from each other by a predetermined distance, a ground selection gate line and a string selection gate line crossing over the respective recess regions, and a plurality of word lines crossing over the main surface of the active region between the ground selection gate line and the string selection gate line. A charge trapping layer may be interposed between the word line and the active region, and between the selection gate line and the active region.
- A charge trapping layer may be interposed between the word line and the active region, and a gate insulating layer may be interposed between the selection gate line and the active region. The device may further include a tunnel insulating layer, a charge trapping layer and a blocking insulating layer, which may be sequentially stacked between the word line and the active region, wherein the word line disposed over the blocking insulating layer may include a metallic material having a work function of about 4.5 eV or greater.
- The word line may include a floating gate on the active region, a control gate electrode formed on the floating gate, and crossing over the active region, and an intergate dielectric layer interposed between the floating gate and the control gate electrode, wherein a tunnel insulating layer may be interposed between the floating gate and the active region. The selection gate line may include a lower selection gate, an upper selection gate on the lower selection gate, and an intergate insulating layer interposed between the lower selection gate and the upper selection gate, the gate insulating layer may be interposed between the lower selection gate and the active region, and the lower selection gate and the upper selection gate being electrically connected to each other.
- A width of the selection gate line may be greater than that of the recess region. The selection gate line may cover the active region at either side of the recess region.
- At least one of the above another features and advantages of the present invention may be separately realized by providing a method for fabricating a semiconductor device, the method including forming a device isolation layer in a semiconductor substrate to define an active region having a main surface extending in a column direction, forming a hard mask having an opening exposing a portion of the active region, etching a portion of the active region using the hard mask as an etch mask to form a recess region, and etching the device isolation layer adjacent to the recess region such that a top surface of the device isolation layer may be lower than a bottom surface of the recess region. The opening may be formed such that it extends in a row direction and exposes the active region and the device isolation layer, and the device isolation layer may be etched using the hard mask as an etch mask.
- Etching of the device isolation layer may be performed before or after the forming of the recess region. The method may further include etching the device isolation layer by etch-back process to make the device isolation layer lower than the main surface of the active region, and forming the recess region of which a bottom surface is higher than a top surface of the recessed device isolation layer. Etching of the device isolation layer by etch-back process may be performed before or after the forming of the recess region. The method may further include forming a word line crossing over the main surface of the active region, and a selection gate line crossing over the recess region.
- The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
-
FIGS. 1A and 1B illustrate cross-sectional views of a semiconductor device according to a first exemplary embodiment of the present invention, respectively taken along a first and a second direction that is perpendicular to the first direction; -
FIGS. 2A through 6A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a first exemplary embodiment of the present invention, taken along the first direction; -
FIGS. 2B through 6B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the first exemplary embodiment of the present invention, taken along the second direction; -
FIGS. 7A and 8A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a second exemplary embodiment of the present invention, taken along the first direction; and -
FIGS. 7B and 8B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the second exemplary embodiment of the present invention, taken along the second direction. - Korean Patent Application No. 2006-102566, filed on Oct. 20, 2006, in the Korean Intellectual Property Office, and entitled: “Semiconductor Device and Method of Fabricating the Same,” is incorporated by reference herein in its entirety.
- The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
- In the figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout the specification.
- Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying figures.
-
FIGS. 1A and 1B illustrate cross-sectional views of a semiconductor device according to a first exemplary embodiment of the present invention, respectively taken along a first and a second direction that is perpendicular to the first direction. - Referring to
FIGS. 1A and 1B , adevice isolation pattern 52 a may be formed in asemiconductor substrate 50 to define anactive region 54. Amain surface region 54 a of theactive region 54 defined, e.g., by two adjacentdevice isolation patterns 52 a, may extend along the first direction, e.g., a column direction, and recess region(s) 60 may be formed in a predetermined region of theactive region 54. In a NAND flash memory device, therecess region 60 may correspond to a region where a gate electrode of a selection transistor is formed. - A ground selection line GSL and a string selection line SSL may cross over the
active region 54, may extend parallel to each other, and may be separated from each other by a predetermined distance. A plurality of word lines WLn may be parallel to and disposed between the ground selection line GSL and the string selection line SSL. Theactive regions 54 under the ground selection line GSL and the string selection line SSL may correspond to therecess regions 60. Therecess regions 60 may include abottom surface 60 a that may be lower than themain surface 54 a of theactive region 54. In embodiments of the invention, a width of therecess region 60 may be smaller than a width of the string and/or ground selection lines SSL and GSL. The string selection line SSL and the ground selection line GSL may overlap theactive region 54 beyond therecess region 60. - Referring to
FIGS. 1A and 1B , anupper surface 52 b of thedevice isolation pattern 52 a disposed adjacent to therecess region 60 may be lower than thebottom surface 60 a of therecess region 60. In some embodiments of the invention, theactive region 54 may include a protrudingupper portion 54 t that protrudes upward beyond theupper surface 52 b of thedevice isolation pattern 52 a. More particularly, e.g., in some embodiments of the invention, when observing a cross-sectional of the selection transistors taken along a direction parallel to the ground or string selection line GSL or SSL, themain surface 54 a of theactive region 54, corresponding to the protrudingupper portion 54 t, may have a rounded, sloped or curved shape. For example, the protrudedupper portion 54 t of theactive region 54 may have a hemispherical-like, trapezoidal-like, or cone-like cross-sectional shape as a result of etching conditions. - In a charge trap type flash memory device, the word line WLn may include a
cell gate electrode 68 and a cellgate insulating layer 62. The cellgate insulating layer 62 may be interposed between thesemiconductor substrate 50 and thecell gate electrode 68. The cellgate insulating layer 62 may be configured with atunnel insulating layer 62 a, acharge trapping layer 62 b, and a blocking insulatinglayer 62 c, which may be stacked in sequence. The ground and string selection lines GSL and SSL may have the same stack structure as the word line WLn. For example, the ground and string selection lines GSL and SSL may include aselection gate electrode 68 and a selection gate insulating layer interposed between thesemiconductor substrate 50 and theselection gate electrode 68. The selection gate insulating layer may have the same stack structure as the cellgate insulating layer 62. That is, the selection gate insulating layer may be configured with atunnel insulating layer 62 a, acharge trapping layer 62 b, and a blocking insulatinglayer 62 c. In other embodiments of the invention, e.g., the selection gate insulating layer may be configured with a monolayer as a gate insulating layer. - A channel region of a memory cell transistor may be formed in the
active region 54 under the word line WLn. A channel region of the ground selection line GSL may be formed in theactive region 54 under the ground selection line GSL, and a channel region of the string selection line SSL may be formed in theactive region 54 under the string selection line SSL. In embodiments of the present invention, the channel regions of the ground and string selection lines GSL and SSL may be formed in therecess regions 60 so that they may have a larger effective channel length than the widths of the ground and string selection lines GSL and SSL. - In some embodiments of the invention, because the
bottom surface 60 a of therecess region 60 may be higher than theupper surface 52 b of thedevice isolation pattern 52 a adjacent thereto, the channel regions of the ground and string selection lines GSL and SSL may be formed along the protrudingupper portion 54 t of theactive region 54. Thus, an effective channel width may be increased, and may be greater than the width of theactive region 54. The gate insulating layers of the ground and string selection lines GSL and SSL may be formed such that they cover the protrudingupper portion 54 t of theactive region 54. More particularly, the gate insulating layers of the ground and string selection lines GSL and SSL may be formed such that they surround sidewalls of the protrudedupper portion 54 t as well as themain surface 54 a of the active region can 54. In such embodiments, themain surface 54 a and portions of the sidewalls of the protrudingupper portion 54 t may be correspond to the channel region. - In conventional devices, when, e.g., the gate insulating layer has a thickness of 20 nm, and an active region has a line-width of 40 nm, the gate insulating layer may fill the recess region. Thus, in such conventional devices, controllability of a gate of the transistor may be hindered. In embodiments of the present invention, however, the
recess region 60 may be formed so as to ensure that therecess region 60 may not be completely filled with the gate insulating layer. More particularly, in some embodiments of the invention, by providing the protrudingupper portion 54 t of theactive region 54, respective portions of the protrudingupper portion 54 t may be used as the channel region of the transistor. - In embodiments of the present invention, the blocking insulating
layer 62 c may have a higher dielectric constant than a dielectric constant of thetunnel insulating layer 62 a. Thecell gate electrode 68 may include a metallic material having a work function greater than about 4.5 eV, wherein the metallic material may be in contact with the blocking insulatinglayer 62 c. For example, in some embodiments of the invention, thecell gate electrode 68 may include abarrier metal layer 64, e.g., a tantalum nitride layer, with ametal layer 66 having excellent conductivity, e.g., a tungsten and/or a tungsten nitride layer, formed on thebarrier metal layer 64. -
FIGS. 2B and 6B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the first exemplary embodiment of the present invention, taken along the second direction. - Referring to
FIGS. 2A and 2B , adevice isolation layer 52 may be formed in asemiconductor substrate 50. Thedevice isolation layer 52 may define theactive region 54. Thedevice isolation layer 54 may be formed using a shallow trench isolation (STI) technique. - The
main surface 54 a of theactive region 54 may extend along the first direction, e.g., a column direction. In embodiments of the invention, theactive regions 54 may be disposed to extend along the first direction, i.e., substantially perpendicular to the first direction along which the gate and/or string selection lines GSL, SSL may extend. - Referring to
FIGS. 3A and 3B , ahard mask 56 may be formed on the resultant structure. Thehard mask 56 may have anopening 58 exposing a portion of theactive region 54. Theopening 58 may extend in the second direction intersecting theactive regions 54 and may expose thedevice isolation layer 52 defining theactive regions 54 as well as theactive regions 54. - In some embodiments of the invention, the
opening 58 may be placed over a region where a channel of the selection transistor will be formed in the NAND type cell array, and may have a smaller width W1 than that of the gate line of the select transistor. - Referring to
FIGS. 4A and 4B , theactive region 54 may be etched to form therecess region 60 using thehard mask 56 as an etch mask. Thebottom surface 60 a of therecess region 60 may be positioned lower than themain surface 54 a of the active region. Therefore, thedevice isolation layer 52 adjacent to therecess region 60 may include aprotrusion 52 t that may be higher than thebottom surface 60 a of therecess region 60. - Referring to
FIGS. 5A and 5B , thedevice isolation layer 52 may then be etched using thehard mask 56 as an etch mask. In some embodiments of the invention, thehard mask 56 may be etched using a different etching solution than that used to etch theactive region 54. Thus, theprotrusions 52 t of thedevice isolation layer 52 adjacent to therecess region 60 may be etched such thedevice isolation pattern 52 b may be formed. More particularly, theupper surface 52 a of thedevice isolation pattern 52 a may be lower than thebottom surface 60 a of therecess region 60. Thus, theactive region 54 may include protruded upper portion(s) 54 t, which may be higher than theupper surface 52 b of thedevice isolation pattern 52 a. The protrudedupper portion 54 t of theactive region 54 may have a hemispherical-like, trapezoidal-like, or cone-like cross-sectional shape as a result of the etching conditions. - Thus, because the
active region 54 may include therecess region 60 having thebottom surface 60 a that may be lower than themain surface 54 a of theactive region 54, and thedevice isolation pattern 52 a adjacent to therecess region 60 may be lower than thebottom surface 60 a of therecess region 60, sidewalls of theactive region 54 may be exposed at a region higher than the device isolation pattern 52 s. More particularly, sidewalls of theactive region 54 may be exposed at a region higher than theupper surface 52 a of thedevice isolation pattern 52 b. - In embodiments of the invention, the
device isolation layer 52 may be etched using thehard mask 56 as an etch mask and thus, only thedevice isolation layer 52 adjacent to therecess region 60 may be etched, i.e., shortened to become lower than theactive region 54. - Alternatively, the
device isolation layer 52 may be etched over an entire surface of the cell array region by an etch-back process after removing thehard mask layer 56, whereby thedevice isolation layer 52 adjacent to the main surface of theactive region 54 may be lower than theactive region 54. In such cases, because thedevice isolation layer 52 may be etched to be lower than thebottom surface 60 a of therecess region 60, theupper surface 52 b of thedevice isolation pattern 52 a adjacent to therecess region 60 may be lower than thebottom surface 60 a of therecess region 60. - Alternatively, it is possible to provide the
device isolation layer 52 at a level lower than therecess region 60 by etching thedevice isolation layer 52 before forming therecess region 60. That is, after etching thedevice isolation layer 52 using thehard mask 56 as an etch mask, theactive region 54 may be etched using thehard mask 56 as an etch mask. Before forming thehard mask 56, thedevice isolation layer 52 may be etched in the cell array so that theupper surface 52 b of thedevice isolation layer 52 becomes lower than themain surface 54 a of theactive region 54. Thereafter, thehard mask 56 may be formed, and therecess region 60 may then be formed using thehard mask 56. - When the top surface of the
device isolation layer 52 is lower than the main surface of theactive region 54, theactive region 54 may have a protrusion that is higher than thedevice isolation layer 52. That is, theactive region 54 may have a sidewall or portion extending from themain surface 54 a thereof that is higher than, i.e., protruding, relative to theupper surface 52 b of thedevice isolation pattern 52 a. As a result, the channel width of the cell transistor can be increased because the channel of the cell transistor can be formed on themain surface 54 a and/or protruding sidewall of theactive region 54. - Referring to
FIGS. 6A and 6B , thehard mask 56 may be removed and thegate insulating layer 62 may then formed on a surface, e.g., an entire surface, of theactive region 54. In charge trap type flash memory devices, thegate insulating layer 62 may have a multi-stacked structure including a charge trapping layer. For example, thegate insulating layer 62 may include thetunnel insulating layer 62 a, thecharge trapping layer 62 b and the blocking insulatinglayer 62 c. - The
gate electrode layer 68 may then be formed on thegate insulating layer 62. Thegate electrode layer 68 may include thebarrier metal layer 64 formed of a metallic material having a work function of about 4.5 eV or greater. For example, thebarrier metal layer 64 may include tantalum nitride. - The
metal layer 66 with excellent conductivity may then be formed on thebarrier metal layer 64. Themetal layer 66 may be formed of tungsten and/or tungsten nitride layer. Subsequently, as shown inFIGS. 1A and 1B , at least thegate electrode layer 68 may be patterned to form a plurality of word lines WLn crossing over theactive region 54, and ground and string section lines GSL and SSL crossing over therecess region 60. - More particularly with regard to the
gate insulating layer 62, in embodiments of the invention, thegate insulating layer 62 may be conformally formed along a surface profile of therecess region 60. In conventional devices, when the minimum width is reduced so that the width of theactive region 54 is two times or less the thickness of thegate insulating layer 62, therecess region 60 was filled with the gate insulating layer. - In embodiments of the present invention, however, because the
recess region 60 may include thebottom surface 60 a that is higher than theupper surface 52 b of thedevice isolation pattern 52 a, therecess region 60 may not be filled with thegate insulating layer 62. Thus, embodiments of the invention may be advantageous over conventional devices at least because embodiments of the invention provide theactive region 54 and therecess region 60 such that therecess region 60 may not be completely filled with a gate insulating layer formed thereon. Rather, in embodiments of the invention, thegate insulating layer 62 may be formed so as to encompass thebottom surface 60 a of therecess region 60, and thus a contact area between theactive region 54 and thegate insulating layer 62 may be enlarged. Therefore, it is possible to increase the channel width of the selection transistor defined in the active region under the ground and string selection lines GSL and SSL. - In the above description of exemplary embodiments, the
gate insulating layer 62 is illustrated as having a multi-stacked structure all over the active region. However, embodiments of the invention are not limited to such a structure. For example, thegate insulating layer 62 may have a multi-stacked structure in a region where the word lines are formed, but may have a monolayer structure in a region where the ground and string selection lines GSL and SSL are formed. In such embodiments, after forming a multi-layeredgate insulating layer 62, the multi-layeredgate insulating layer 62 may be partially removed to form a monolayered gate insulating layer. -
FIGS. 7A and 8A illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to a second exemplary embodiment of the present invention, taken along the first direction.FIGS. 7B and 8B illustrate cross-sectional views of stages in a method of fabricating a semiconductor device according to the second exemplary embodiment of the present invention, taken along the second direction. - Referring to
FIGS. 7A and 7B , a floating gate type flash memory device may include a floating gate. In the following description, in general, only differences between the first exemplary embodiment described above and the second exemplary embodiment illustrated inFIGS. 7A through 8B will be described. Similar to the exemplary process described above with reference toFIGS. 5A and 5B , therecess region 60 may be formed in theactive region 54, and at least thedevice isolation pattern 52 a adjacent to therecess region 60 may be etched to have a top surface thereof lower than thebottom surface 60 a of therecess region 60. - Afterwards, a
gate insulating layer 162 may be formed on theactive region 54, and a floatinggate layer 164, anintergate dielectric layer 166, and a controlgate electrode layer 168 may be formed on thegate insulating layer 162. In some embodiments of the invention, theintergate dielectric layer 166 may be formed such that it has an opening OX over therecess region 60, so that the floatinggate layer 164 and the controlgate electrode layer 168 may be connected to each other. - The
gate insulating layer 162 may be a thin tunnel insulating layer at a portion where the cell transistor will be formed, whereas it may be thicker than the tunnel insulating layer at a portion where the selection transistor will be formed. - Referring to
FIGS. 8A and 8B , the controlgate electrode layer 168, theintergate dielectric layer 166 and the floatinggate layer 164 may be sequentially patterned to form word lines WLn crossing over theactive region 54 and the ground and selection lines GSL and SSL crossing over therecess region 60. - The word line WLn may have a multi-stacked structure in which the floating
gate layer 164, theintergate dielectric layer 166 and thecontrol gate layer 168 are stacked over thetunnel insulating layer 162 in sequence. Each of the ground and string selection lines GSL and SSL may include a lower selection gate corresponding to the floatinggate 164, an intergate insulating layer corresponding to theintergate dielectric layer 166, and an upper selection gate corresponding to thecontrol gate electrode 168. - Embodiments of the present invention enable an effective channel width as well as an effective channel length of a transistor, including a channel formed in the recess region, to be secured. When one or more aspects of the present invention is applied to the flash memory device, it is possible to provide a selection transistor having a larger effective channel length than a gate linewidth. In addition, even if the minimum linewidth is reduced, embodiments of the invention enable suppression and/or prevention of degradation of gate controllability for the channel while securing the effective channel width as well.
- Furthermore, when forming an active region where a cell transistor will be formed such that it protrudes higher than a device isolation layer, a channel width of the cell transistor can be increased.
- Exemplary embodiments of the present invention have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
Claims (9)
1-20. (canceled)
21. A flash memory device, comprising:
an active region including a main surface and a pair of recess regions of which a bottom surface is lower than the main surface, the pair of recess regions disposed in the active region, and separated from each other by a predetermined distance;
a ground selection gate line and a string selection gate line crossing over the respective recess regions; and
at the least one of a word line crossing over the main surface of the active region between the ground selection gate line and the string selection gate line.
22. The flash memory device as claimed in claim 21 , wherein a charge trapping layer is interposed between the word line and the active region, and between the active region and a selection gate line including the ground selection gate line and the string selection gate line.
23. The flash memory device as claimed in claim 21 , wherein a charge trapping layer is interposed between the word line and the active region, and a gate insulating layer is interposed between the active region and a selection gate line including the ground selection gate line and the string selection gate line.
24. The flash memory device as claimed in claim 21 , further comprising a tunnel insulating layer, a charge trapping layer and a blocking insulating layer, which are sequentially stacked between the word line and the active region,
wherein the word line disposed over the blocking insulating layer includes a metallic material having a work function of about 4.5 eV or greater.
25. The flash memory device as claimed in claim 21 , wherein the word line comprises:
a floating gate on the active region;
a control gate electrode formed on the floating gate, and crossing over the active region; and
an intergate dielectric layer interposed between the floating gate and the control gate electrode,
wherein a tunnel insulating layer is interposed between the floating gate and the active region.
26. The flash memory device as claimed in claim 21 , wherein the ground selection gate line and the string selection gate line comprise:
a lower selection gate;
an upper selection gate on the lower selection gate; and
an intergate insulating layer interposed between the lower selection gate and the upper selection gate,
the gate insulating layer being interposed between the lower selection gate and the active region, and the lower selection gate and the upper selection gate being electrically connected to each other.
27. The flash memory device as claimed in claim 21 , wherein widths of the ground selection and the string selection gate line are greater than that of the recess regions.
28. The flash memory device as claimed in claim 27 , wherein the ground selection gate line and the string selection gate line cover the active region at either side of the respective pair of recess regions.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/980,399 US20110095351A1 (en) | 2006-10-20 | 2010-12-29 | Semiconductor devices and methods of fabricating the same |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR2006-102566 | 2006-10-20 | ||
KR1020060102566A KR100882797B1 (en) | 2006-10-20 | 2006-10-20 | Emiconductor devcie and method of fabricating the same |
US11/709,814 US7863676B2 (en) | 2006-10-20 | 2007-02-23 | Semiconductor devices and methods of fabricating the same |
US12/980,399 US20110095351A1 (en) | 2006-10-20 | 2010-12-29 | Semiconductor devices and methods of fabricating the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/709,814 Continuation US7863676B2 (en) | 2006-10-20 | 2007-02-23 | Semiconductor devices and methods of fabricating the same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20110095351A1 true US20110095351A1 (en) | 2011-04-28 |
Family
ID=39317095
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/709,814 Active 2029-09-11 US7863676B2 (en) | 2006-10-20 | 2007-02-23 | Semiconductor devices and methods of fabricating the same |
US12/980,399 Abandoned US20110095351A1 (en) | 2006-10-20 | 2010-12-29 | Semiconductor devices and methods of fabricating the same |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/709,814 Active 2029-09-11 US7863676B2 (en) | 2006-10-20 | 2007-02-23 | Semiconductor devices and methods of fabricating the same |
Country Status (2)
Country | Link |
---|---|
US (2) | US7863676B2 (en) |
KR (1) | KR100882797B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2016173414A (en) * | 2015-03-16 | 2016-09-29 | 旭化成株式会社 | Pellicle |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101692364B1 (en) * | 2010-11-15 | 2017-01-05 | 삼성전자 주식회사 | Fabricating method of non volatile memory device and non volatile memory device thereby |
KR101627557B1 (en) | 2014-12-08 | 2016-06-07 | 주식회사 포스코 | Press apparatus and jig for exchaning press mold |
US9443862B1 (en) * | 2015-07-24 | 2016-09-13 | Sandisk Technologies Llc | Select gates with select gate dielectric first |
US9613971B2 (en) | 2015-07-24 | 2017-04-04 | Sandisk Technologies Llc | Select gates with central open areas |
Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4964080A (en) * | 1990-03-09 | 1990-10-16 | Intel Corporation | Three-dimensional memory cell with integral select transistor |
US5023680A (en) * | 1988-11-10 | 1991-06-11 | Texas Instruments Incorporated | Floating-gate memory array with silicided buried bitlines and with single-step-defined floating gates |
US5429971A (en) * | 1994-10-03 | 1995-07-04 | United Microelectronics Corporation | Method of making single bit erase flash EEPROM |
US20030123307A1 (en) * | 2001-12-27 | 2003-07-03 | Samsung Electronics Co., Ltd. | Non-volatile memory device and a method of fabricating the same |
US20060023558A1 (en) * | 2004-05-04 | 2006-02-02 | Cho Myoung-Kwan | Non-volatile memory devices that include a selection transistor having a recessed channel and methods of fabricating the same |
US20060029887A1 (en) * | 2004-08-06 | 2006-02-09 | Chang-Woo Oh | Semiconductor devices having a support structure for an active layer pattern and methods of forming the same |
US20060060910A1 (en) * | 2004-09-17 | 2006-03-23 | Ching-Sung Yang | Nonvolatile memory and manufacturing method and operating method thereof |
US7084477B2 (en) * | 2002-06-24 | 2006-08-01 | Hitachi, Ltd. | Semiconductor device and manufacturing method of the same |
US20060222966A1 (en) * | 2005-04-01 | 2006-10-05 | Samsung Electronics Co., Ltd. | Mask layout and method of forming contact pad using the same |
US20070284650A1 (en) * | 2006-06-07 | 2007-12-13 | Josef Willer | Memory device and a method of forming a memory device |
US7332755B2 (en) * | 2005-04-29 | 2008-02-19 | Hynix Semiconductor Inc. | Transistor structure of memory device and method for fabricating the same |
US20080315285A1 (en) * | 2007-06-19 | 2008-12-25 | Samsung Electronics Co., Ltd. | Non-volatile memory devices and methods of fabricating the same |
US20090200596A1 (en) * | 2005-11-01 | 2009-08-13 | Samsung Electronics Co., Ltd. | Fabrication method and structure for providing a recessed channel in a nonvolatile memory device |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20060038620A (en) * | 2004-10-30 | 2006-05-04 | 주식회사 하이닉스반도체 | Method for fabricating semiconductor device |
KR100657823B1 (en) | 2004-12-28 | 2006-12-14 | 주식회사 하이닉스반도체 | Semiconductor device with recessed gate and method for manufacturing the same |
-
2006
- 2006-10-20 KR KR1020060102566A patent/KR100882797B1/en active IP Right Grant
-
2007
- 2007-02-23 US US11/709,814 patent/US7863676B2/en active Active
-
2010
- 2010-12-29 US US12/980,399 patent/US20110095351A1/en not_active Abandoned
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5023680A (en) * | 1988-11-10 | 1991-06-11 | Texas Instruments Incorporated | Floating-gate memory array with silicided buried bitlines and with single-step-defined floating gates |
US4964080A (en) * | 1990-03-09 | 1990-10-16 | Intel Corporation | Three-dimensional memory cell with integral select transistor |
US5429971A (en) * | 1994-10-03 | 1995-07-04 | United Microelectronics Corporation | Method of making single bit erase flash EEPROM |
US20030123307A1 (en) * | 2001-12-27 | 2003-07-03 | Samsung Electronics Co., Ltd. | Non-volatile memory device and a method of fabricating the same |
US7084477B2 (en) * | 2002-06-24 | 2006-08-01 | Hitachi, Ltd. | Semiconductor device and manufacturing method of the same |
US7547943B2 (en) * | 2004-05-04 | 2009-06-16 | Samsung Electronics Co., Ltd. | Non-volatile memory devices that include a selection transistor having a recessed channel and methods of fabricating the same |
US20060023558A1 (en) * | 2004-05-04 | 2006-02-02 | Cho Myoung-Kwan | Non-volatile memory devices that include a selection transistor having a recessed channel and methods of fabricating the same |
US20060029887A1 (en) * | 2004-08-06 | 2006-02-09 | Chang-Woo Oh | Semiconductor devices having a support structure for an active layer pattern and methods of forming the same |
US20060060910A1 (en) * | 2004-09-17 | 2006-03-23 | Ching-Sung Yang | Nonvolatile memory and manufacturing method and operating method thereof |
US20060222966A1 (en) * | 2005-04-01 | 2006-10-05 | Samsung Electronics Co., Ltd. | Mask layout and method of forming contact pad using the same |
US7332755B2 (en) * | 2005-04-29 | 2008-02-19 | Hynix Semiconductor Inc. | Transistor structure of memory device and method for fabricating the same |
US20090200596A1 (en) * | 2005-11-01 | 2009-08-13 | Samsung Electronics Co., Ltd. | Fabrication method and structure for providing a recessed channel in a nonvolatile memory device |
US20070284650A1 (en) * | 2006-06-07 | 2007-12-13 | Josef Willer | Memory device and a method of forming a memory device |
US20080315285A1 (en) * | 2007-06-19 | 2008-12-25 | Samsung Electronics Co., Ltd. | Non-volatile memory devices and methods of fabricating the same |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2016173414A (en) * | 2015-03-16 | 2016-09-29 | 旭化成株式会社 | Pellicle |
Also Published As
Publication number | Publication date |
---|---|
KR100882797B1 (en) | 2009-02-10 |
US7863676B2 (en) | 2011-01-04 |
US20080093656A1 (en) | 2008-04-24 |
KR20080035911A (en) | 2008-04-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR100645065B1 (en) | Fin fet and non-volatile memory device having the same and method of forming the same | |
US7829931B2 (en) | Nonvolatile memory devices having control electrodes configured to inhibit parasitic coupling capacitance | |
US7897456B2 (en) | Non-volatile memory device and method for fabricating the same | |
US7283392B2 (en) | NAND flash memory device and methods of its formation and operation | |
US20070108498A1 (en) | Non-volatile memory devices having floating gates and related methods of forming the same | |
KR100760633B1 (en) | Charge trap type non-volatile memory device and method of forming the same | |
KR20070025015A (en) | Non-volatile memory device and method for manufacturing the same | |
US10115809B2 (en) | Semiconductor memory device and method of manufacturing the same | |
KR100773356B1 (en) | Non-volatile memory device having separate charge trap patterns and method of fabricating the same | |
US8502295B2 (en) | Nonvolatile memory device | |
US20110095351A1 (en) | Semiconductor devices and methods of fabricating the same | |
US7439577B2 (en) | Semiconductor memory and method for manufacturing the same | |
US7432159B2 (en) | Electrically erasable programmable read-only memory (EEPROM) device and methods of fabricating the same | |
US20070023823A1 (en) | Nonvolatile semiconductor memory device and related method | |
JP2006093230A (en) | Nonvolatile semiconductor storage device | |
US7541243B2 (en) | Methods of forming integrated circuit devices having gate electrodes formed on non-uniformly thick gate insulating layers | |
US9685451B2 (en) | Nonvolatile memory device and method for fabricating the same | |
US20080093678A1 (en) | NAND type non-volatile memory device and method of forming the same | |
US7915120B2 (en) | Method of fabricating non-volatile memory device | |
US7041555B2 (en) | Method for manufacturing flash memory device | |
US8076206B2 (en) | Method for manufacturing SONOS flash memory | |
US20080061356A1 (en) | Eeprom device and methods of forming the same | |
US20080203458A1 (en) | Semiconductor Memory Device and Method of Fabricating the Same | |
US8119475B2 (en) | Method of forming gate of semiconductor device | |
JP2010212454A (en) | Nonvolatile semiconductor memory device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |