KR20080088095A - Method for forming gate of semiconductor device - Google Patents
Method for forming gate of semiconductor device Download PDFInfo
- Publication number
- KR20080088095A KR20080088095A KR1020070030515A KR20070030515A KR20080088095A KR 20080088095 A KR20080088095 A KR 20080088095A KR 1020070030515 A KR1020070030515 A KR 1020070030515A KR 20070030515 A KR20070030515 A KR 20070030515A KR 20080088095 A KR20080088095 A KR 20080088095A
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- South Korea
- Prior art keywords
- polysilicon film
- gate
- type polysilicon
- film
- forming
- Prior art date
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 27
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 95
- 229920005591 polysilicon Polymers 0.000 claims abstract description 95
- 239000000758 substrate Substances 0.000 claims abstract description 26
- 238000005530 etching Methods 0.000 claims abstract description 15
- 239000002184 metal Substances 0.000 claims abstract description 9
- 238000002955 isolation Methods 0.000 claims description 11
- 239000012535 impurity Substances 0.000 claims description 10
- 150000002500 ions Chemical class 0.000 claims description 10
- 230000000694 effects Effects 0.000 description 5
- 230000005684 electric field Effects 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000011165 process development Methods 0.000 description 1
- 239000000126 substance Substances 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
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
- H01L29/10—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions with semiconductor regions connected to an electrode not carrying current to be rectified, amplified or switched and such electrode being part of a semiconductor device which comprises three or more electrodes
- H01L29/1066—Gate region of field-effect devices with PN junction 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
- H01L29/40—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
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/49—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET
- H01L29/4916—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a silicon layer, e.g. polysilicon doped with boron, phosphorus or nitrogen
- H01L29/4925—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a silicon layer, e.g. polysilicon doped with boron, phosphorus or nitrogen with a multiple layer structure, e.g. several silicon layers with different crystal structure or grain arrangement
- H01L29/4933—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a silicon layer, e.g. polysilicon doped with boron, phosphorus or nitrogen with a multiple layer structure, e.g. several silicon layers with different crystal structure or grain arrangement with a silicide layer contacting the silicon layer, e.g. Polycide 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
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Computer Hardware Design (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Electrodes Of Semiconductors (AREA)
- Insulated Gate Type Field-Effect Transistor (AREA)
Abstract
A method of forming a gate of a semiconductor device includes: recessing a semiconductor substrate to form a gate groove; Forming a gate insulating film on an entire surface of the substrate including the gate groove; Forming a P-type polysilicon film on the gate insulating film; Etching the P-type polysilicon film and the gate insulating film so that the P-type polysilicon film and the gate insulating film remain only under the gate groove; Forming an oxide film on a sidewall of an upper portion of the gate groove in which the P-type polysilicon film and the gate insulating film remain; Forming an N-type polysilicon film on the entire surface of the substrate including the oxide film and the P-type polysilicon film; And sequentially forming a metal-based film and a hard mask film on the N-type polysilicon film.
Description
1A to 1H are cross-sectional views illustrating processes for forming a gate of a semiconductor device in accordance with an embodiment of the present invention.
Explanation of symbols on the main parts of the drawings
100
H: Gate groove 104: Gate insulating film
106: p-type polysilicon film 108: oxide film
110: N-type polysilicon film 112: metal film
114: hard mask film 116: gate
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a gate of a semiconductor device, and to forming a gate cell of a semiconductor device, which may improve device characteristics and reliability by improving a gate induced drain leakage (GIDL) phenomenon in manufacturing a DRAM cell transistor. It is about a method.
In recent years, as the design rules of highly integrated MOSFETs are rapidly reduced to 100 nm or less, the channel length and width of transistors are correspondingly reduced, and the doping concentration to the junction region is increased. Therefore, the junction leakage current increases with the increase of the electric field. As a result, it is difficult to obtain a threshold voltage value required by a high density device using a conventional planar channel structure transistor, and reaches a limit in improving refresh characteristics.
Accordingly, a method of implementing a semiconductor device having various types of recess channels capable of securing an effective channel length of the transistor, and a channel having a three-dimensional structure capable of extending a channel width. Research on the idea of how to implement the semiconductor device and the actual process development is being actively conducted.
When the semiconductor device having the recess channel is manufactured, the effective length of the channel is increased as compared with the conventional planar type device, so that short channel effect is suppressed, and even a small ion implantation dose is desired. Since the threshold voltage can be ensured, the junction leakage current is reduced to improve the refresh characteristics. In addition, cell characteristics are improved by improving drain-induced barrier lowering (DIBL) and breakdown voltage (BVds).
In addition, a fin transistor structure has been proposed as a transistor having a channel having a three-dimensional structure, and the protrusion transistor has an active region formed by etching a device isolation region to protrude an active region to form a fin pattern. A gate line is formed to expose both sides and the top surface of the substrate, and then surround the protruding active region (pin pattern). In this case, a short channel effect due to an increase in drain induced barrier low (DIBL) Effect) is suppressed, and the channel is formed on all three exposed surfaces of the active region, which greatly improves the current drive characteristics of the channel.
On the other hand, as the integration of the MOSFET device progresses, the gate line width is reduced due to the decrease in the cell size, and the decrease in the line width of the gate electrode causes the channel length to decrease.
As such, the decrease in the channel length due to the high integration of the MOSFET increases the doping concentration of the semiconductor substrate. As a result, the leakage current (LC) of the device increases and the threshold voltage (Vt). The so-called short channel effect phenomenon, which is drastically lowered, is further intensified.
Therefore, in the NMOS device, a P-type polysilicon film having a large work function of a gate is applied to adjust a threshold voltage Vt through channel doping of a boron system.
When the P-type polysilicon film is used instead of the N-type polysilicon film in the NMOS device, the work function of the gate end is increased, thereby bringing about a change in the surface potential in the channel, thereby lowering the channel Threshold voltage (Vt) can be secured even with a dose.
However, in the above-described prior art, the potential difference is increased by the work function in the overlap region between the N-type junction region and the gate to which the P-type polysilicon film is applied, and as a result, a GIDL phenomenon is obtained. This deepening degrades the refresh characteristics of the device.
In this case, the GIDL phenomenon is a phenomenon in which current leaks due to concentration of an electric field at both corners of the gate and the substrate in contact with each other, and is a major factor in reducing the refresh time of the device. It is a challenge that must be solved.
The present invention provides a method of forming a gate of a semiconductor device that can improve device characteristics and reliability by improving a gate induced drain leakage (GIDL) phenomenon in manufacturing a DRAM cell transistor.
A method of forming a gate of a semiconductor device according to the present invention comprises the steps of: recessing a semiconductor substrate to form a groove for the gate; Forming a gate insulating film on an entire surface of the substrate including the gate groove; Forming a P-type polysilicon film on the gate insulating film; Etching the P-type polysilicon film and the gate insulating film so that the P-type polysilicon film and the gate insulating film remain only under the gate groove; Forming an oxide film on a sidewall of an upper portion of the gate groove in which the P-type polysilicon film and the gate insulating film remain; Forming an N-type polysilicon film on the entire surface of the substrate including the oxide film and the P-type polysilicon film; And sequentially forming a metal-based film and a hard mask film on the N-type polysilicon film.
Here, the etching of the P-type polysilicon film and the gate insulating film is performed such that the P-type polysilicon film remains at a thickness of 700 to 900 만큼 under the gate groove.
The P-type polysilicon film is formed of a polysilicon film doped with a P-type impurity dose of 5 × 10 18 to 5 × 10 22 ions / cm 2 .
The N-type polysilicon film is formed to a thickness of 300 to 500 kPa.
The N-type polysilicon film is formed of a polysilicon film doped with a dose of 5 × 10 18 to 5 × 10 22 ions / cm 2 of N-type impurities.
In addition, the method for forming a gate of a semiconductor device according to the present invention comprises the steps of forming an isolation film defining an active region of the semiconductor substrate; Etching the device isolation layer to expose some side surfaces of the active region to form a fin pattern having a protruding shape of the active region; Recessing the protruding active region to form a groove for a gate; Forming a gate insulating film on an entire surface of the substrate including the gate groove; Forming a P-type polysilicon film on the gate insulating film; Etching the P-type polysilicon film and the gate insulating film so that the P-type polysilicon film and the gate insulating film remain only under the gate groove; Forming an oxide film on a sidewall of an upper portion of the gate groove in which the P-type polysilicon film and the gate insulating film remain; Forming an N-type polysilicon film on the entire surface of the substrate including the oxide film and the P-type polysilicon film; And sequentially forming a metal-based film and a hard mask film on the N-type polysilicon film.
The etching of the P-type polysilicon film and the gate insulating film may be performed such that the P-type polysilicon film remains in the lower portion of the gate groove by a thickness of 700 to 900 Å.
The P-type polysilicon film is formed of a polysilicon film doped with a P-type impurity dose of 5 × 10 18 to 5 × 10 22 ions / cm 2 .
The N-type polysilicon film is formed to a thickness of 300 to 500 kPa.
The N-type polysilicon film is formed of a polysilicon film doped with a dose of 5 × 10 18 to 5 × 10 22 ions / cm 2 of N-type impurities.
(Example)
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
According to the present invention, a high concentration P-type polysilicon film is formed in a lower portion of a gate groove in which a channel of a recess gate is formed when forming a gate of a semiconductor device in which a polysilicon film is applied as a gate conductive film, and the sidewall of the gate groove is formed. A high concentration N-type polysilicon film is formed on the top.
In this case, a P-type polysilicon film having a large work function is formed in a portion where the channel is formed, thereby securing a threshold voltage Vt even with a low channel dose, thereby increasing driving current of a semiconductor device. In addition, by forming an N-type polysilicon layer on the sidewall of the gate groove, a gate current drain (LCID) phenomenon may be improved to reduce leakage current (LC).
1A to 1H are cross-sectional views illustrating processes of forming a gate of a semiconductor device according to an exemplary embodiment of the present invention.
Referring to FIG. 1A, a trench is formed by etching the device isolation region of the
Subsequently, a mask pattern (not shown) is formed on the resultant of the
Referring to FIG. 1B, a gate
Referring to FIG. 1C, a P-
Referring to FIG. 1D, the P-
Referring to FIG. 1E, an
Referring to FIG. 1F, the gate is formed on a resultant of the
The N-
Referring to FIG. 1G, a
Referring to FIG. 1H, a gate is formed on the gate groove H by etching the
Thereafter, although not shown, a series of subsequent known processes are sequentially performed to complete the gate of the semiconductor device according to the embodiment of the present invention.
Here, the present invention forms a high-concentration P-type polysilicon film having a large work function in the lower portion of the gate groove in which the channel of the gate is formed, thereby changing a low channel dose through a surface potential change in the channel. Also, the threshold voltage Vt may be secured to increase the driving current of the semiconductor device.
In addition, the present invention forms a high-concentration N-type polysilicon film in the upper portion of the gate groove in which the electric field is concentrated, thereby improving the GIDL phenomenon and causing the electric field to be concentrated at both edge portions of the gate and the substrate. The leakage current can be reduced, thereby improving the refresh characteristics of the semiconductor device.
Accordingly, the present invention forms a high concentration P-type polysilicon film under the gate groove and a high concentration N-type polysilicon film on the gate groove, thereby increasing the driving current of the semiconductor device and reducing the GIDL phenomenon. Since it can improve, a semiconductor element characteristic and reliability can be improved effectively.
Meanwhile, in the above-described embodiment of the present invention, a method of improving the GIDL phenomenon when the recess gate is formed to increase the effective channel length of the gate has been described, but as another embodiment of the present invention, the channel width of the gate is increased. The same effect can be obtained when the device isolation layer is etched to increase the ridge-type gate exposed by some side surfaces of the active region to increase.
As mentioned above, although the present invention has been illustrated and described with reference to specific embodiments, the present invention is not limited thereto, and the following claims are not limited to the scope of the present invention without departing from the spirit and scope of the present invention. It can be easily understood by those skilled in the art that can be modified and modified.
As described above, the present invention can increase the driving current of the semiconductor device by forming a high concentration P-type polysilicon film under the gate groove in which the channel of the gate is formed.
In addition, the present invention by forming a high concentration of the N-type polysilicon film in the upper portion of the gate groove in which the electric field is concentrated, it is possible to reduce the leakage current by improving the GIDL (Gate Induced Drain Leakage) phenomenon, In addition, the refresh characteristics of the semiconductor device can be improved.
Accordingly, the present invention forms a high concentration P-type polysilicon film under the gate groove and a high concentration N-type polysilicon film on the gate groove, thereby increasing the driving current of the semiconductor device and reducing the GIDL phenomenon. Since it can improve, a semiconductor element characteristic and reliability can be improved effectively.
Claims (10)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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KR1020070030515A KR20080088095A (en) | 2007-03-28 | 2007-03-28 | Method for forming gate of semiconductor device |
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KR1020070030515A KR20080088095A (en) | 2007-03-28 | 2007-03-28 | Method for forming gate of semiconductor device |
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KR20080088095A true KR20080088095A (en) | 2008-10-02 |
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KR1020070030515A KR20080088095A (en) | 2007-03-28 | 2007-03-28 | Method for forming gate of semiconductor device |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101105433B1 (en) * | 2009-07-03 | 2012-01-17 | 주식회사 하이닉스반도체 | Semiconductor device with buried gate and method for manufacturing the same |
CN105322021A (en) * | 2014-08-04 | 2016-02-10 | 瑞萨电子株式会社 | Semiconductor device and method for manufacturing same |
-
2007
- 2007-03-28 KR KR1020070030515A patent/KR20080088095A/en not_active Application Discontinuation
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101105433B1 (en) * | 2009-07-03 | 2012-01-17 | 주식회사 하이닉스반도체 | Semiconductor device with buried gate and method for manufacturing the same |
US8120099B2 (en) | 2009-07-03 | 2012-02-21 | Hynix Semiconductor Inc. | Semiconductor device with buried gate and method for fabricating the same |
CN105322021A (en) * | 2014-08-04 | 2016-02-10 | 瑞萨电子株式会社 | Semiconductor device and method for manufacturing same |
CN105322021B (en) * | 2014-08-04 | 2020-11-24 | 瑞萨电子株式会社 | Semiconductor device and method for manufacturing the same |
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