US20130277737A1 - Semiconductor device and method of manufacturing the same - Google Patents
Semiconductor device and method of manufacturing the same Download PDFInfo
- Publication number
- US20130277737A1 US20130277737A1 US13/917,612 US201313917612A US2013277737A1 US 20130277737 A1 US20130277737 A1 US 20130277737A1 US 201313917612 A US201313917612 A US 201313917612A US 2013277737 A1 US2013277737 A1 US 2013277737A1
- Authority
- US
- United States
- Prior art keywords
- gate
- oxide layer
- gate oxide
- semiconductor device
- trench
- 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 claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title description 10
- 229910052751 metal Inorganic materials 0.000 claims abstract description 41
- 239000002184 metal Substances 0.000 claims abstract description 41
- 125000006850 spacer group Chemical group 0.000 claims abstract description 30
- 239000000758 substrate Substances 0.000 claims abstract description 29
- 238000002955 isolation Methods 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 14
- 238000005530 etching Methods 0.000 description 6
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 5
- 229920005591 polysilicon Polymers 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000003989 dielectric material Substances 0.000 description 3
- 230000005684 electric field Effects 0.000 description 3
- 230000015654 memory Effects 0.000 description 3
- 230000005641 tunneling Effects 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ILCYGSITMBHYNK-UHFFFAOYSA-N [Si]=O.[Hf] Chemical compound [Si]=O.[Hf] ILCYGSITMBHYNK-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 229910000449 hafnium oxide Inorganic materials 0.000 description 1
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
Images
Classifications
-
- 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
- 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
-
- 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
- H01L29/42364—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the insulating layer, e.g. thickness or uniformity
-
- 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
- H01L29/42364—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the insulating layer, e.g. thickness or uniformity
- H01L29/42368—Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the insulating layer, e.g. thickness or uniformity the thickness being non-uniform
-
- 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
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66545—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
-
- 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
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66568—Lateral single gate silicon transistors
- H01L29/66613—Lateral single gate silicon transistors with a gate recessing step, e.g. using local oxidation
- H01L29/66621—Lateral single gate silicon transistors with a gate recessing step, e.g. using local oxidation using etching to form a recess at the gate location
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/01—Manufacture or treatment
- H10B12/02—Manufacture or treatment for one transistor one-capacitor [1T-1C] memory cells
- H10B12/05—Making the transistor
- H10B12/053—Making the transistor the transistor being at least partially in a trench in the substrate
Definitions
- the present invention relates to a semiconductor device with improved gate refresh characteristics and a method of fabricating the same.
- the size of an active region and a channel length of a transistor formed in the active region are reduced.
- the channel length of a transistor is reduced, short channel effect or source/drain punch-through occurs, which negatively influences the electric field or electric potential in the channel of the transistor.
- a threshold voltage of the DRAM cells is reduced and a leakage current increases, thereby degrading the refresh characteristics of DRAMs.
- a method of increasing the gate channel length of the device formed on a substrate has been suggested. For example, even if the memory cells of a DRAM device are scaled down to a very small size, a transistor having a recessed channel retains fairly good refresh characteristics.
- a source/drain region is formed by implanting impurities into a substrate.
- a mask opening a portion of the substrate in which a recessed channel is to be formed is formed and the exposed portion of the substrate is etched using the mask to form a trench in the substrate.
- a gate oxide layer is formed on an inner wall of the trench.
- the gate oxide layer includes a high dielectric (high-k) material layer such as a silicon oxide layer, a hafnium oxide layer and a hafnium silicon oxide layer.
- a gate conductive layer fills the trench.
- the gate conductive layer includes a stacking structure of polysilicon/metal or metal/polysilicon/metal, which has a lower resistance characteristic than polysilicon while having a property similar to polysilicon.
- the gate conductive layer is isotropically etched using a gate mask to form a gate electrode, thereby completing a transistor having the gate electrode and the source/drain.
- a high dielectric material layer is used as the gate oxide layer and a stacking structure, which includes a polysilicon layer on a metal layer, is formed on the high dielectric material layer as the gate conductive layer.
- a transistor having a recessed channel is formed by the related art, due to low etch selectivity between the metal layer used as a gate conductive layer and the high dielectric material layer, when the high dielectric layer is etched to form the gate electrode, silicon substrate is removed.
- GIDL gate induced drain leakage
- the present invention is directed to providing a semiconductor device capable of preventing the degradation of refresh characteristics due to GIDL caused by concentration of an electric field in an overlap area between gates, which occurs when reducing the thickness of a gate oxide layer to improve controllability of a gate as the integrity of the semiconductor device increases, and a method of manufacturing the same.
- a semiconductor device includes a gate metal buried within a trench in a semiconductor substrate including an active region defined by a device isolation layer, a spacer pattern disposed on an upper portion of a sidewall of the gate metal, a first gate oxide layer disposed between the spacer pattern and the trench, a second gate oxide layer disposed below the first gate oxide layer and the gate metal, and a junction region disposed in the active region to overlap the first gate oxide layer.
- the first gate oxide layer may have a thicker thickness than the second gate oxide layer.
- the first gate oxide layer may have the thickness of 70 ⁇ to 100 ⁇ .
- the second oxide layer may have a thickness of 50 ⁇ to 60 ⁇ .
- junction region and the gate metal may be spaced by the spacer pattern and the first gate oxide layer.
- a semiconductor device includes a first buried gate formed at a first level in a substrate; a second buried gate extending from the first buried gate and formed at a second level in the substrate, the second level being higher than the first level; a junction region formed at a side of the second buried gate at the second level; a spacer pattern formed between the junction region and the second buried gate at the second level; and a first gate oxide layer formed between the spacer pattern and the junction region, wherein a thickness and a material of the spacer pattern and the first gate oxide layer are configured to inhibit leakage between the buried gate and the junction region.
- the device further comprising a second gate oxide layer formed between the first buried gate and the substrate, wherein the first gate oxide layer is formed to be thicker than the second gate oxide layer.
- a method of manufacturing a semiconductor device includes forming a trench in a semiconductor substrate including an active region defined by a device isolation layer, forming an insulating layer on an inner surface of the trench, forming a sacrificial metal pattern on the insulating layer to be filled within a lower portion of the trench, forming a spacer pattern at a sidewall of the trench on the sacrificial metal pattern, removing the sacrificial metal pattern, removing the insulating layer using the spacer pattern as a mask to form a first gate oxide layer, forming a second gate oxide layer on a surface of the trench from which the sacrificial metal pattern is removed, forming a gate metal on the second gate oxide layer to overlap the spacer pattern, and forming a junction region in the active region to overlap the first gate oxide layer by performing an ion implantation process.
- the forming the trench may include forming a hard mask pattern on the semiconductor substrate and etching the semiconductor substrate using the hard mask pattern as a mask.
- the forming the insulating layer on the inner surface of the trench may include oxidizing a surface of the trench.
- the forming the insulating layer on the inner surface of the trench may include forming an oxide layer having a thickness of 70 ⁇ to 100 ⁇ .
- the forming the sacrificial metal pattern may include forming a sacrificial metal layer on the insulating layer and performing an etching back process for the sacrificial metal layer by taking a channel region, which is to be formed within the semiconductor substrate, into consideration.
- the forming the spacer pattern may include forming a spacer insulating layer on the sacrificial metal pattern and the insulating layer and performing an etching back process for the spacer insulating layer.
- the removing the insulating layer may include performing a cleaning process for the insulating layer.
- the forming the second oxide layer may include oxidizing a surface of the trench exposed by the spacer pattern.
- the forming the second oxide layer may include forming an oxide layer having a thickness of 50 ⁇ to 60 ⁇ .
- the method may further include forming an insulating layer on the gate metal after forming the gate metal.
- a method of manufacturing a semiconductor device includes forming a trench in a substrate, wherein the trench includes a lower part located at a first level and an upper part located at a second level, forming an insulating layer over a surface of the trench at the first level and at the second level, forming a sacrificial metal pattern in the trench at the first level, forming a spacer pattern at a sidewall of the trench at the second level, removing the sacrificial metal pattern, removing the insulating layer at the first level and allowing the insulating layer at the second level to remain to form a first gate oxide layer, forming a gate electrode in the trench so as to extend from the first level to the second level and forming a junction region in the substrate at a side of the first gate oxide layer at the second level.
- FIG. 1 is a cross-sectional view illustrating a semiconductor device according to an exemplary embodiment of the present invention.
- FIGS. 2A to 2H are cross-sectional views illustrating a method of manufacturing a semiconductor device according to an exemplary embodiment of the present invention.
- Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the particular shapes of regions illustrated herein, but may include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. It is also understood that when a layer 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.
- a semiconductor device includes a gate metal 118 buried in a trench 106 , which is formed in a semiconductor substrate including an active region defined by a device isolation layer 102 ; a spacer pattern 114 disposed over an upper portion of a sidewall of the gate metal 118 ; a first gate oxide layer 110 a disposed between the spacer pattern 114 and a sidewall of the trench 106 , a second gate oxide layer 116 disposed below the first gate oxide layer 110 a and the gate metal 118 ; and a junction region 122 disposed in the active region to overlap the first gate oxide layer 110 a.
- the semiconductor device further includes an insulating layer 120 disposed over the gate metal 118 and a hard mask pattern 108 defining the trench 106 .
- a thickness of the first oxide layer 110 a may be thicker than that of the second gate oxide layer 116 .
- the first gate oxide layer 110 a may have a thickness of 70 ⁇ to 100 ⁇ and the second gate oxide layer 116 may have a thickness of 50 ⁇ to 60 ⁇ .
- a hard mask pattern 108 is formed on a semiconductor substrate 100 , which includes an active region 104 defined by a device isolation layer 102 .
- the semiconductor substrate 100 is etched using the hard mask pattern 108 as a mask to form a trench 106 .
- the trench 106 may be a region where a gate is to be formed.
- an insulating layer 110 is formed over the surface of the trench 106 .
- the insulating layer 110 may be formed to a thickness of 70 ⁇ to 100 ⁇ .
- a sacrificial metal layer is formed on the semiconductor substrate 100 including the trench 106 and then an etching back process is performed to form a sacrificial metal pattern 112 in a lower portion of the trench 106 .
- the sacrificial metal pattern 112 defines a channel region.
- a spacer insulating layer is formed on the sacrificial metal pattern 112 , the insulating layer 110 , and the hard mask pattern 108 and an etching back process for the spacer insulating layer is performed to form a spacer pattern 114 only on sidewalls of the insulating layer 110 and the hard mask pattern 108 .
- the spacer pattern 114 prevents a gate oxide layer from being damaged in the following process.
- the sacrificial metal pattern 112 which fills the lower portion of the trench 106 , is removed.
- a cleaning process is performed so that the insulating layer under the sacrificial metal pattern 112 is also removed, thus exposing a surface of the trench 106 .
- a first gate oxide layer 110 a is obtained along an upper inner wall of the trench.
- the first gate oxide layer 110 a can prevent gate induced drain leakage (GIDL) current due to a direct tunneling between a gate electrode and a drain region.
- GIDL gate induced drain leakage
- a second gate oxide layer 116 is formed over the surface of the trench 106 exposed by removing the first oxide layer 110 a .
- the second gate oxide layer 116 may be formed by performing an oxidation process on the semiconductor substrate 100 .
- the second gate oxide layer 116 may have a shallower thickness than the first gate oxide layer 110 a and may have a thickness of 50 ⁇ to 60 ⁇ .
- the area where the second gate oxide layer 116 is formed is an area in which a channel is to be formed. Accordingly, the second gate oxide layer 116 is thinly formed to easily control a gate.
- a gate conductive layer is formed within the trench 106 and then an etching back process is performed to form a gate 118 buried in the trench 106 .
- the gate 118 may extend over the spacer pattern 114 .
- an insulating layer 120 is formed in the trench 106 to be over the gate 118 and an ion implantation process is performed on the semiconductor substrate 100 to form a junction region 122 .
- the junction region 122 may be formed at such a level that it overlaps with the space pattern 114 and the first gate oxide layer 110 a . That is, the junction region 122 is spaced apart from the gate 118 by the thicknesses of the spacer pattern 114 and the first gate oxide layer 110 a to suppress the direct tunneling effect in an “A” area, thereby reducing GIDL.
- the gate oxide layer is thickly formed in an overlapping area between the gate and the junction to reduce GIDL, thereby improving refresh characteristics and reducing parasitic capacitance to improve characteristics of the semiconductor device.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Insulated Gate Type Field-Effect Transistor (AREA)
- Semiconductor Memories (AREA)
Abstract
A semiconductor device includes a gate metal buried within a trench included in a semiconductor substrate including an active region defined by an isolation layer, a spacer pattern disposed on an upper portion of a sidewall of a gate metal, a first gate oxide layer disposed between the spacer pattern and the trench, a second gate oxide layer disposed below the first gate oxide layer and the gate metal, and a junction region disposed in the active region to overlap the first gate oxide layer.
Description
- The present application claims priority to Korean patent application number 10-2010-0063421 filed on 01 Jul. 2010, which is incorporated by reference in its entirety.
- 1. Technical Field
- The present invention relates to a semiconductor device with improved gate refresh characteristics and a method of fabricating the same.
- 2. Related Art
- With the high integration degree of semiconductor devices, the size of an active region and a channel length of a transistor formed in the active region are reduced. As the channel length of a transistor is reduced, short channel effect or source/drain punch-through occurs, which negatively influences the electric field or electric potential in the channel of the transistor. For example, when a short channel effect is generated in an access transistor adapted to memory cells of dynamic random access memories (DRAMs), a threshold voltage of the DRAM cells is reduced and a leakage current increases, thereby degrading the refresh characteristics of DRAMs. Thus, in order to suppress the short channel effect, a method of increasing the gate channel length of the device formed on a substrate has been suggested. For example, even if the memory cells of a DRAM device are scaled down to a very small size, a transistor having a recessed channel retains fairly good refresh characteristics.
- Hereinafter, a method of manufacturing a transistor having a recessed channel in the related art will be described. A source/drain region is formed by implanting impurities into a substrate. A mask opening a portion of the substrate in which a recessed channel is to be formed is formed and the exposed portion of the substrate is etched using the mask to form a trench in the substrate. Subsequently, a gate oxide layer is formed on an inner wall of the trench. At this time, the gate oxide layer includes a high dielectric (high-k) material layer such as a silicon oxide layer, a hafnium oxide layer and a hafnium silicon oxide layer. A gate conductive layer fills the trench. The gate conductive layer includes a stacking structure of polysilicon/metal or metal/polysilicon/metal, which has a lower resistance characteristic than polysilicon while having a property similar to polysilicon. The gate conductive layer is isotropically etched using a gate mask to form a gate electrode, thereby completing a transistor having the gate electrode and the source/drain.
- Thus, as the integrity degree of the semiconductor device rapidly increases, in order to reduce a gate leakage current and power consumption, a high dielectric material layer is used as the gate oxide layer and a stacking structure, which includes a polysilicon layer on a metal layer, is formed on the high dielectric material layer as the gate conductive layer. However, when a transistor having a recessed channel is formed by the related art, due to low etch selectivity between the metal layer used as a gate conductive layer and the high dielectric material layer, when the high dielectric layer is etched to form the gate electrode, silicon substrate is removed.
- On the other hand, as integrity of the semiconductor device increases, the thickness of the gate oxide layer is reduced to improve controllability of the gate. As a result, an electric field is concentrated at an area between the gates thus causing gate induced drain leakage (GIDL). That is, since an overlap between the gate and a junction region is increased by bridges between a word line and a bit line or between word lines, GIDL current is increased by direct tunneling between the gate electrode and the drain region. Such a GIDL current seriously degrades a semiconductor device, such as DRAM, having a recessed channel.
- The present invention is directed to providing a semiconductor device capable of preventing the degradation of refresh characteristics due to GIDL caused by concentration of an electric field in an overlap area between gates, which occurs when reducing the thickness of a gate oxide layer to improve controllability of a gate as the integrity of the semiconductor device increases, and a method of manufacturing the same.
- According to one aspect of an exemplary embodiment, a semiconductor device includes a gate metal buried within a trench in a semiconductor substrate including an active region defined by a device isolation layer, a spacer pattern disposed on an upper portion of a sidewall of the gate metal, a first gate oxide layer disposed between the spacer pattern and the trench, a second gate oxide layer disposed below the first gate oxide layer and the gate metal, and a junction region disposed in the active region to overlap the first gate oxide layer.
- The first gate oxide layer may have a thicker thickness than the second gate oxide layer.
- The first gate oxide layer may have the thickness of 70
Åto 100 Å. - The second oxide layer may have a thickness of 50 Å to 60 Å.
- The junction region and the gate metal may be spaced by the spacer pattern and the first gate oxide layer.
- According to another aspect of another exemplary embodiment, a semiconductor device includes a first buried gate formed at a first level in a substrate; a second buried gate extending from the first buried gate and formed at a second level in the substrate, the second level being higher than the first level; a junction region formed at a side of the second buried gate at the second level; a spacer pattern formed between the junction region and the second buried gate at the second level; and a first gate oxide layer formed between the spacer pattern and the junction region, wherein a thickness and a material of the spacer pattern and the first gate oxide layer are configured to inhibit leakage between the buried gate and the junction region.
- The device further comprising a second gate oxide layer formed between the first buried gate and the substrate, wherein the first gate oxide layer is formed to be thicker than the second gate oxide layer.
- According to another aspect of another exemplary embodiment, a method of manufacturing a semiconductor device includes forming a trench in a semiconductor substrate including an active region defined by a device isolation layer, forming an insulating layer on an inner surface of the trench, forming a sacrificial metal pattern on the insulating layer to be filled within a lower portion of the trench, forming a spacer pattern at a sidewall of the trench on the sacrificial metal pattern, removing the sacrificial metal pattern, removing the insulating layer using the spacer pattern as a mask to form a first gate oxide layer, forming a second gate oxide layer on a surface of the trench from which the sacrificial metal pattern is removed, forming a gate metal on the second gate oxide layer to overlap the spacer pattern, and forming a junction region in the active region to overlap the first gate oxide layer by performing an ion implantation process.
- The forming the trench may include forming a hard mask pattern on the semiconductor substrate and etching the semiconductor substrate using the hard mask pattern as a mask.
- The forming the insulating layer on the inner surface of the trench may include oxidizing a surface of the trench.
- The forming the insulating layer on the inner surface of the trench may include forming an oxide layer having a thickness of 70 Å to 100 Å.
- The forming the sacrificial metal pattern may include forming a sacrificial metal layer on the insulating layer and performing an etching back process for the sacrificial metal layer by taking a channel region, which is to be formed within the semiconductor substrate, into consideration.
- The forming the spacer pattern may include forming a spacer insulating layer on the sacrificial metal pattern and the insulating layer and performing an etching back process for the spacer insulating layer.
- The removing the insulating layer may include performing a cleaning process for the insulating layer.
- The forming the second oxide layer may include oxidizing a surface of the trench exposed by the spacer pattern.
- The forming the second oxide layer may include forming an oxide layer having a thickness of 50 Å to 60 Å.
- The method may further include forming an insulating layer on the gate metal after forming the gate metal.
- According to another aspect of another exemplary embodiment, a method of manufacturing a semiconductor device includes forming a trench in a substrate, wherein the trench includes a lower part located at a first level and an upper part located at a second level, forming an insulating layer over a surface of the trench at the first level and at the second level, forming a sacrificial metal pattern in the trench at the first level, forming a spacer pattern at a sidewall of the trench at the second level, removing the sacrificial metal pattern, removing the insulating layer at the first level and allowing the insulating layer at the second level to remain to form a first gate oxide layer, forming a gate electrode in the trench so as to extend from the first level to the second level and forming a junction region in the substrate at a side of the first gate oxide layer at the second level.
- These and other features, aspects, and embodiments are described below in the section entitled “DESCRIPTION OF EXEMPLARY EMBODIMENT.”
- The above and other aspects, features, and other advantages of the subject matter of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
-
FIG. 1 is a cross-sectional view illustrating a semiconductor device according to an exemplary embodiment of the present invention; and -
FIGS. 2A to 2H are cross-sectional views illustrating a method of manufacturing a semiconductor device according to an exemplary embodiment of the present invention. - Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the particular shapes of regions illustrated herein, but may include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. It is also understood that when a layer 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.
- Hereinafter, exemplary embodiments of the present invention will be described with reference to accompanying drawings.
- Referring to
FIG. 1 , a semiconductor device according to an exemplary embodiment of the present invention includes agate metal 118 buried in atrench 106, which is formed in a semiconductor substrate including an active region defined by adevice isolation layer 102; aspacer pattern 114 disposed over an upper portion of a sidewall of thegate metal 118; a firstgate oxide layer 110 a disposed between thespacer pattern 114 and a sidewall of thetrench 106, a secondgate oxide layer 116 disposed below the firstgate oxide layer 110 a and thegate metal 118; and ajunction region 122 disposed in the active region to overlap the firstgate oxide layer 110 a. - The semiconductor device further includes an
insulating layer 120 disposed over thegate metal 118 and ahard mask pattern 108 defining thetrench 106. Here, a thickness of thefirst oxide layer 110 a may be thicker than that of the secondgate oxide layer 116. Specifically, the firstgate oxide layer 110 a may have a thickness of 70 Å to 100 Å and the secondgate oxide layer 116 may have a thickness of 50 Å to 60 Å. - Hereinafter, a method of manufacturing a semiconductor device having the above-described structure according to an exemplary embodiment of the present invention will be described.
- Referring to
FIG. 2A , ahard mask pattern 108 is formed on asemiconductor substrate 100, which includes anactive region 104 defined by adevice isolation layer 102. Thesemiconductor substrate 100 is etched using thehard mask pattern 108 as a mask to form atrench 106. Thetrench 106 may be a region where a gate is to be formed. - Referring to
FIG. 2B , an insulatinglayer 110 is formed over the surface of thetrench 106. Here, the insulatinglayer 110 may be formed to a thickness of 70 Å to 100 Å. - Referring to
FIG. 2C , a sacrificial metal layer is formed on thesemiconductor substrate 100 including thetrench 106 and then an etching back process is performed to form asacrificial metal pattern 112 in a lower portion of thetrench 106. Here, thesacrificial metal pattern 112 defines a channel region. - Referring to
FIG. 2D , a spacer insulating layer is formed on thesacrificial metal pattern 112, the insulatinglayer 110, and thehard mask pattern 108 and an etching back process for the spacer insulating layer is performed to form aspacer pattern 114 only on sidewalls of the insulatinglayer 110 and thehard mask pattern 108. Thespacer pattern 114 prevents a gate oxide layer from being damaged in the following process. - Referring to
FIG. 2E , thesacrificial metal pattern 112, which fills the lower portion of thetrench 106, is removed. A cleaning process is performed so that the insulating layer under thesacrificial metal pattern 112 is also removed, thus exposing a surface of thetrench 106. As a result, a firstgate oxide layer 110 a is obtained along an upper inner wall of the trench. As described above, the firstgate oxide layer 110 a can prevent gate induced drain leakage (GIDL) current due to a direct tunneling between a gate electrode and a drain region. - Referring to
FIG. 2F , a secondgate oxide layer 116 is formed over the surface of thetrench 106 exposed by removing thefirst oxide layer 110 a. Here, the secondgate oxide layer 116 may be formed by performing an oxidation process on thesemiconductor substrate 100. The secondgate oxide layer 116 may have a shallower thickness than the firstgate oxide layer 110 a and may have a thickness of 50 Å to 60 Å. The area where the secondgate oxide layer 116 is formed is an area in which a channel is to be formed. Accordingly, the secondgate oxide layer 116 is thinly formed to easily control a gate. - Referring to
FIG. 2G , a gate conductive layer is formed within thetrench 106 and then an etching back process is performed to form agate 118 buried in thetrench 106. Thegate 118 may extend over thespacer pattern 114. - Referring to
FIG. 2H , an insulatinglayer 120 is formed in thetrench 106 to be over thegate 118 and an ion implantation process is performed on thesemiconductor substrate 100 to form ajunction region 122. Here, thejunction region 122 may be formed at such a level that it overlaps with thespace pattern 114 and the firstgate oxide layer 110 a. That is, thejunction region 122 is spaced apart from thegate 118 by the thicknesses of thespacer pattern 114 and the firstgate oxide layer 110 a to suppress the direct tunneling effect in an “A” area, thereby reducing GIDL. - As described above, according to an exemplary embodiment of the present invention, the gate oxide layer is thickly formed in an overlapping area between the gate and the junction to reduce GIDL, thereby improving refresh characteristics and reducing parasitic capacitance to improve characteristics of the semiconductor device.
- The above embodiments of the present invention are illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the embodiment described herein. Nor is the invention limited to any specific type of semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
Claims (8)
1.-11. (canceled)
12. A semiconductor device, comprising:
a gate metal buried within a trench formed in a semiconductor substrate, the semiconductor including an active region defined by a device isolation layer;
a spacer pattern formed over an upper portion of the gate metal and extending upward from a sidewall of the gate metal;
a first gate oxide layer disposed between the spacer pattern and a sidewall of the trench;
a second gate oxide layer extending from the bottom of the first gate oxide layer to be formed under the gate metal; and
a junction region formed at a side of the gate metal while having the first gate oxide layer interposed therebetween.
13. The semiconductor device of claim 12 , wherein the first gate oxide layer has a thicker thickness than the second gate oxide layer.
14. The semiconductor device of claim 12 , wherein the first gate oxide layer has the thickness of 70 Å to 100 Å.
15. The semiconductor device of claim 12 , wherein the second oxide layer has a thickness of 50 Å to 60 Å.
16. The semiconductor device of claim 12 , wherein the junction region and the gate metal is spaced apart by the spacer pattern and the first gate oxide layer.
17. A semiconductor device, comprising:
a first buried gate formed at a first level in a substrate;
a second buried gate extending from the first buried gate and formed at a second level in the substrate, the second level being higher than the first level;
a junction region formed at a side of the second buried gate at the second level;
a spacer pattern formed between the junction region and the second buried gate at the second level; and
a first gate oxide layer formed between the spacer pattern and the junction region,
wherein a thickness and a material of the spacer pattern and the first gate oxide layer are configured to inhibit leakage between the buried gate and the junction region.
18. The semiconductor device of claim 17 , the device further comprising a second gate oxide layer formed between the first buried gate and the substrate,
wherein the first gate oxide layer is formed to be thicker than the second gate oxide layer.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/917,612 US20130277737A1 (en) | 2010-07-01 | 2013-06-13 | Semiconductor device and method of manufacturing the same |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020100063421A KR101061296B1 (en) | 2010-07-01 | 2010-07-01 | Method for forming semiconductor device |
KR10-2010-0063421 | 2010-07-01 | ||
US13/175,202 US8486819B2 (en) | 2010-07-01 | 2011-07-01 | Semiconductor device and method of manufacturing the same |
US13/917,612 US20130277737A1 (en) | 2010-07-01 | 2013-06-13 | Semiconductor device and method of manufacturing the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/175,202 Division US8486819B2 (en) | 2010-07-01 | 2011-07-01 | Semiconductor device and method of manufacturing the same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20130277737A1 true US20130277737A1 (en) | 2013-10-24 |
Family
ID=44934047
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/175,202 Active 2031-11-06 US8486819B2 (en) | 2010-07-01 | 2011-07-01 | Semiconductor device and method of manufacturing the same |
US13/917,612 Abandoned US20130277737A1 (en) | 2010-07-01 | 2013-06-13 | Semiconductor device and method of manufacturing the same |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/175,202 Active 2031-11-06 US8486819B2 (en) | 2010-07-01 | 2011-07-01 | Semiconductor device and method of manufacturing the same |
Country Status (2)
Country | Link |
---|---|
US (2) | US8486819B2 (en) |
KR (1) | KR101061296B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2555664A (en) * | 2017-03-07 | 2018-05-09 | Gall Thomson Environmental Ltd | Valve assembly for use in a fluid conduit |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5646416B2 (en) * | 2011-09-01 | 2014-12-24 | 株式会社東芝 | Manufacturing method of semiconductor device |
KR101853316B1 (en) | 2012-03-29 | 2018-04-30 | 삼성전자주식회사 | Transistor, semiconductor device and a semiconductor module including the same |
KR101930751B1 (en) * | 2012-08-07 | 2019-03-12 | 삼성전자 주식회사 | Semiconductor device and method for fabricating thereof |
KR20140079088A (en) * | 2012-12-18 | 2014-06-26 | 에스케이하이닉스 주식회사 | Semiconductor Device and Fabrication Method Thereof |
KR20140089650A (en) | 2013-01-03 | 2014-07-16 | 삼성디스플레이 주식회사 | Liquid crystal display and manufacturing method thereof |
KR101847630B1 (en) * | 2013-04-01 | 2018-05-24 | 삼성전자주식회사 | Semiconductor device and semiconductor module |
WO2016204771A1 (en) * | 2015-06-18 | 2016-12-22 | Intel Corporation | Bottom-up fill (buf) of metal features for semiconductor structures |
FR3038774B1 (en) | 2015-07-08 | 2018-03-02 | Stmicroelectronics (Rousset) Sas | METHOD FOR PRODUCING A HIGH-VOLTAGE TRANSISTOR WITH A REDUCED SIZE, AND CORRESPONDING INTEGRATED CIRCUIT |
KR102596497B1 (en) | 2018-11-16 | 2023-10-30 | 삼성전자주식회사 | Semiconductor device and method for fabricating the same |
KR20200131069A (en) | 2019-05-13 | 2020-11-23 | 삼성전자주식회사 | Method for manufacturing a memory device |
CN111900201A (en) * | 2020-06-22 | 2020-11-06 | 中国科学院微电子研究所 | Semiconductor structure and manufacturing method |
US11700724B2 (en) | 2021-05-14 | 2023-07-11 | Winbond Electronics Corp. | Semiconductor memory structure and method for manufacturing the same |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20080003055A (en) * | 2006-06-30 | 2008-01-07 | 주식회사 하이닉스반도체 | Mosfet device and method of manufacturing the same |
US20080121990A1 (en) * | 2006-11-27 | 2008-05-29 | Elpida Memory, Inc. | Semiconductor device and manufacture method therefor |
US20090127609A1 (en) * | 2007-09-10 | 2009-05-21 | Han Sung-Hee | Method of fabricating recess channel transistor having locally thick dielectrics and related devices |
US20090176342A1 (en) * | 2008-01-03 | 2009-07-09 | Samsung Electronics Co., Ltd. | Method of fabricating semiconductor device having deifferential gate dielectric layer and related device |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4961822A (en) * | 1989-04-17 | 1990-10-09 | Liao Kuan Y | Fully recessed interconnection scheme with titanium-tungsten and selective CVD tungsten |
JPH04320330A (en) * | 1991-04-19 | 1992-11-11 | Sharp Corp | Method for forming contact portion of semiconductor device |
JP4932088B2 (en) * | 2001-02-19 | 2012-05-16 | ルネサスエレクトロニクス株式会社 | Insulated gate type semiconductor device manufacturing method |
JP5008247B2 (en) * | 2003-04-03 | 2012-08-22 | セイコーインスツル株式会社 | Manufacturing method of vertical MOS transistor |
KR100621563B1 (en) | 2004-11-03 | 2006-09-19 | 삼성전자주식회사 | Non-volatile memory device and method for fabricating the same |
KR100650828B1 (en) * | 2005-06-16 | 2006-11-27 | 주식회사 하이닉스반도체 | Method for forming recess gate of semiconductor devices |
JP4773182B2 (en) * | 2005-10-28 | 2011-09-14 | エルピーダメモリ株式会社 | Manufacturing method of semiconductor device |
KR100732304B1 (en) * | 2006-03-23 | 2007-06-25 | 주식회사 하이닉스반도체 | Semiconductor device and method for fabricating the same |
US20080150013A1 (en) * | 2006-12-22 | 2008-06-26 | Alpha & Omega Semiconductor, Ltd | Split gate formation with high density plasma (HDP) oxide layer as inter-polysilicon insulation layer |
KR20080089016A (en) | 2007-03-30 | 2008-10-06 | 주식회사 하이닉스반도체 | Method for manufactring semiconductor device |
US8384152B2 (en) * | 2007-09-20 | 2013-02-26 | Rohm Co., Ltd. | Semiconductor device having trench gate VDMOSFET and method of manufacturing the same |
KR20100030019A (en) | 2008-09-09 | 2010-03-18 | 주식회사 하이닉스반도체 | Method for manufacturing semiconductor device |
US9190495B2 (en) * | 2008-09-22 | 2015-11-17 | Samsung Electronics Co., Ltd. | Recessed channel array transistors, and semiconductor devices including a recessed channel array transistor |
US7786528B2 (en) * | 2009-01-14 | 2010-08-31 | Force Mos Technology Co., Ltd. | Metal schemes of trench MOSFET for copper bonding |
KR101095686B1 (en) * | 2009-07-24 | 2011-12-20 | 주식회사 하이닉스반도체 | Semiconductor memory device and method for fabricating the same |
US8178922B2 (en) * | 2010-01-14 | 2012-05-15 | Force Mos Technology Co., Ltd. | Trench MOSFET with ultra high cell density and manufacture thereof |
TWI403235B (en) * | 2010-07-14 | 2013-07-21 | Taiwan Memory Company | Manufacturing method for a buried circuit structure |
-
2010
- 2010-07-01 KR KR1020100063421A patent/KR101061296B1/en active IP Right Grant
-
2011
- 2011-07-01 US US13/175,202 patent/US8486819B2/en active Active
-
2013
- 2013-06-13 US US13/917,612 patent/US20130277737A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20080003055A (en) * | 2006-06-30 | 2008-01-07 | 주식회사 하이닉스반도체 | Mosfet device and method of manufacturing the same |
US20080121990A1 (en) * | 2006-11-27 | 2008-05-29 | Elpida Memory, Inc. | Semiconductor device and manufacture method therefor |
US20090127609A1 (en) * | 2007-09-10 | 2009-05-21 | Han Sung-Hee | Method of fabricating recess channel transistor having locally thick dielectrics and related devices |
US20090176342A1 (en) * | 2008-01-03 | 2009-07-09 | Samsung Electronics Co., Ltd. | Method of fabricating semiconductor device having deifferential gate dielectric layer and related device |
Non-Patent Citations (1)
Title |
---|
Machine Translation of KR 2008003055. * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2555664A (en) * | 2017-03-07 | 2018-05-09 | Gall Thomson Environmental Ltd | Valve assembly for use in a fluid conduit |
GB2555664B (en) * | 2017-03-07 | 2019-05-01 | Gall Thomson Environmental Ltd | Valve assembly for use in a fluid conduit |
Also Published As
Publication number | Publication date |
---|---|
KR101061296B1 (en) | 2011-08-31 |
US8486819B2 (en) | 2013-07-16 |
US20120001258A1 (en) | 2012-01-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8486819B2 (en) | Semiconductor device and method of manufacturing the same | |
US7368769B2 (en) | MOS transistor having a recessed gate electrode and fabrication method thereof | |
US8299517B2 (en) | Semiconductor device employing transistor having recessed channel region and method of fabricating the same | |
KR100819562B1 (en) | Semiconductor device having retrograde region and method of fabricating the same | |
US7795670B2 (en) | Semiconductor device and method for fabricating the same | |
US7858477B2 (en) | Forming a buried bit line in a bulb-shaped trench | |
US7701002B2 (en) | Semiconductor device having buried gate electrode and method of fabricating the same | |
US9018695B2 (en) | Semiconductor device and method for manufacturing the same | |
US8507349B2 (en) | Semiconductor device employing fin-type gate and method for manufacturing the same | |
US20110018057A1 (en) | Semiconductor memory device and method for fabricating the same | |
US20120012925A1 (en) | Semiconductor device and method for manufacturing the same | |
US20110304028A1 (en) | Semiconductor device and method of manufacturing the same | |
KR20060128472A (en) | Mos transistor having a recessed gate electrode and fabrication method thereof | |
KR20060121066A (en) | Mos transistor having a recess channel and fabrication method thereof | |
US8658491B2 (en) | Manufacturing method of transistor structure having a recessed channel | |
US7851855B2 (en) | Semiconductor device and a method for manufacturing the same | |
US8318558B2 (en) | Semiconductor device and method for forming the same | |
KR20130107490A (en) | Semiconductor device and method for manufacturing the same | |
KR101110545B1 (en) | Semiconductor device and method for manufacturing the same | |
US20120012923A1 (en) | Semiconductor device and method for forming the same | |
JP2013062350A (en) | Semiconductor device and manufacturing method of the same | |
KR20110070318A (en) | Method of fabricating semiconductor device having buried-typed metal recess gate | |
KR20050122474A (en) | Method for forming the transistor with recess gate | |
KR100598170B1 (en) | Transistor with recess gate and forming method thereof | |
JP2013093451A (en) | Semiconductor device manufacturing method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SK HYNIX INC., KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KIM, WAN SOO;REEL/FRAME:030660/0465 Effective date: 20130618 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |