US20140264492A1 - Counter-doped low-power finfet - Google Patents
Counter-doped low-power finfet Download PDFInfo
- Publication number
- US20140264492A1 US20140264492A1 US13/871,270 US201313871270A US2014264492A1 US 20140264492 A1 US20140264492 A1 US 20140264492A1 US 201313871270 A US201313871270 A US 201313871270A US 2014264492 A1 US2014264492 A1 US 2014264492A1
- Authority
- US
- United States
- Prior art keywords
- fin
- doped
- finfet
- halo
- semiconductor
- 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.)
- Granted
Links
- 239000004065 semiconductor Substances 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 29
- 230000004888 barrier function Effects 0.000 claims abstract description 20
- 239000000758 substrate Substances 0.000 claims abstract description 13
- 238000005468 ion implantation Methods 0.000 claims abstract description 11
- 239000002019 doping agent Substances 0.000 claims description 40
- 239000010410 layer Substances 0.000 claims description 26
- 229910000577 Silicon-germanium Inorganic materials 0.000 claims description 13
- 239000013545 self-assembled monolayer Substances 0.000 claims description 12
- 239000002094 self assembled monolayer Substances 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 7
- 238000004151 rapid thermal annealing Methods 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 6
- 229910052731 fluorine Inorganic materials 0.000 claims description 5
- 239000011737 fluorine Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 1
- 238000000231 atomic layer deposition Methods 0.000 claims 1
- 229910052799 carbon Inorganic materials 0.000 claims 1
- 239000002356 single layer Substances 0.000 abstract description 5
- 125000004429 atom Chemical group 0.000 description 18
- 125000005843 halogen group Chemical group 0.000 description 16
- 239000007943 implant Substances 0.000 description 16
- 125000006850 spacer group Chemical group 0.000 description 9
- 239000002243 precursor Substances 0.000 description 7
- 210000002381 plasma Anatomy 0.000 description 5
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- 238000000137 annealing Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 125000001475 halogen functional group Chemical group 0.000 description 4
- 239000005388 borosilicate glass Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 238000013508 migration Methods 0.000 description 3
- 230000005012 migration Effects 0.000 description 3
- 239000005360 phosphosilicate glass Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 238000010884 ion-beam technique Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000002161 passivation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- RUIKOPXSCCGLOM-UHFFFAOYSA-N 1-diethoxyphosphorylpropane Chemical compound CCCP(=O)(OCC)OCC RUIKOPXSCCGLOM-UHFFFAOYSA-N 0.000 description 1
- BMIBJCFFZPYJHF-UHFFFAOYSA-N 2-methoxy-5-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine Chemical compound COC1=NC=C(C)C=C1B1OC(C)(C)C(C)(C)O1 BMIBJCFFZPYJHF-UHFFFAOYSA-N 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- 238000005280 amorphization Methods 0.000 description 1
- RBFQJDQYXXHULB-UHFFFAOYSA-N arsane Chemical compound [AsH3] RBFQJDQYXXHULB-UHFFFAOYSA-N 0.000 description 1
- 229910000070 arsenic hydride Inorganic materials 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000011960 computer-aided design Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000004678 hydrides Chemical class 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- AUHZEENZYGFFBQ-UHFFFAOYSA-N mesitylene Substances CC1=CC(C)=CC(C)=C1 AUHZEENZYGFFBQ-UHFFFAOYSA-N 0.000 description 1
- 125000001827 mesitylenyl group Chemical group [H]C1=C(C(*)=C(C([H])=C1C([H])([H])[H])C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 125000004437 phosphorous atom Chemical group 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- QGLVEAGMVUQOJP-UHFFFAOYSA-N prop-2-enylboronic acid Chemical compound OB(O)CC=C QGLVEAGMVUQOJP-UHFFFAOYSA-N 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- RMZAYIKUYWXQPB-UHFFFAOYSA-N trioctylphosphane Chemical compound CCCCCCCCP(CCCCCCCC)CCCCCCCC RMZAYIKUYWXQPB-UHFFFAOYSA-N 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 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
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
-
- 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
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/785—Field effect transistors with field effect produced by an insulated gate having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
-
- 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
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
- H01L21/26586—Bombardment with radiation with high-energy radiation producing ion implantation characterised by the angle between the ion beam and the crystal planes or the main crystal surface
-
- 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
- H01L29/66787—Unipolar field-effect transistors with an insulated gate, i.e. MISFET with a gate at the side of the channel
- H01L29/66795—Unipolar field-effect transistors with an insulated gate, i.e. MISFET with a gate at the side of the channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
- H01L29/66803—Unipolar field-effect transistors with an insulated gate, i.e. MISFET with a gate at the side of the channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET with a step of doping the vertical sidewall, e.g. using tilted or multi-angled implants
-
- 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
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/7842—Field effect transistors with field effect produced by an insulated gate means for exerting mechanical stress on the crystal lattice of the channel region, e.g. using a flexible substrate
- H01L29/7848—Field effect transistors with field effect produced by an insulated gate means for exerting mechanical stress on the crystal lattice of the channel region, e.g. using a flexible substrate the means being located in the source/drain region, e.g. SiGe source and drain
-
- 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
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
- H01L21/26506—Bombardment with radiation with high-energy radiation producing ion implantation in group IV semiconductors
-
- 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
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
- H01L21/26506—Bombardment with radiation with high-energy radiation producing ion implantation in group IV semiconductors
- H01L21/26513—Bombardment with radiation with high-energy radiation producing ion implantation in group IV semiconductors of electrically active species
-
- 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
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
- H01L29/161—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table including two or more of the elements provided for in group H01L29/16, e.g. alloys
- H01L29/165—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table including two or more of the elements provided for in group H01L29/16, e.g. alloys in different semiconductor regions, e.g. heterojunctions
Definitions
- One or more embodiments of the present invention relate to methods of manufacture of semiconductor devices.
- Halo implant methods have been used to improve a short channel effect (SCE) in planar field effect transistors (“FETs”).
- SCE short channel effect
- FETs planar field effect transistors
- an angled halo ion implantation with dopants of opposite polarity from that of the source and drain regions is used to increase the substrate doping adjacent to the source and drain regions of an FET in a way that effectively reduces the extent of the source and drain at the edges and/or under the sidewall spacers but at some depth below the semiconductor substrate surface.
- a fin-shaped field effect transistor (“FinFET”) provides lower power due to the fully depleted (lightly doped) thin body of the fin and the resulting reduced or reverse SCE with improved drain-induced barrier lowering (DIBL).
- a FinFET generally has a lightly doped channel and less random dopant fluctuation (RDF) than a planar FET.
- a fin is formed on a substrate, wherein the fin has a height between two and six times its width, and a length defining a channel between source and drain ends.
- the fin comprises a lightly doped semiconductor.
- a conformal region of counter-doped semiconductor is formed on the surface of the fin.
- Halo-doped regions are formed by angled ion implantation.
- the halo-doped regions are disposed in the lower portion of the source and drain and adjacent to the fin.
- Energy band barriers can be formed at the edges of the halo-doped regions by angled ion implantation.
- the conformal region of counter-doped semiconductor is formed by wet chemical doping method using a molecular monolayer deposition (MLD) process.
- a solution comprising the dopant molecules is applied to the fin surface.
- a sacrificial oxide layer is added, to encapsulates the fin surface with dopant.
- the dopant atoms can be made to migrate into the surface of the fin by performing a rapid thermal annealing (RTA) at about 950-1150° C. The oxide layer can be removed after annealing.
- RTA rapid thermal annealing
- the conformal region of counter-doped semiconductor is formed by exposing the fin surface to a plasma comprising dopant atoms.
- the conformal region of counter-doped semiconductor can be formed by forming a conformal oxide layer comprising dopant atoms on the fin surface.
- the dopant atoms can be made to migrate into the surface of the fin by performing a rapid thermal annealing (RTA) at about 950-1150° C.
- RTA rapid thermal annealing
- the oxide layer can be removed after annealing.
- Novel FinFET devices having a fin on a substrate, the fin having a height of 2 to 6 times of its width, and a length defining a channel between source and drain ends.
- the fin comprises a lightly doped conductor.
- a conformal counter-doped region is disposed on the top and sides of the fin. Halo-doped regions are disposed in the lower portion of the source and drain and adjacent to the sidewall spacers on the fin.
- Band barriers can be disposed at the edges of the halo-doped regions.
- the band barriers can comprise barrier atoms comprising halo-implant dopants (p- or n-type dopants) with fluorine for point defect reduction as well as to provide a barrier against dopant migration.
- the lightly doped semiconductor can be n-doped, with the counter-doped region p-doped, and the halo-doped regions n-doped for a low power p-channel FinFET.
- the lightly doped semiconductor can be p-doped, with the counter-doped semiconductor n-doped, and the halo-doped regions p-doped for a low power n-channel FinFET.
- the lightly doped semiconductor can comprise Si bulk or SOI fins.
- the semiconductor used for the source and drain connections can comprise p-doped SiGe for p-type FinFETs, where the Ge fraction is greater than 50% by atomic fraction for achieving a maximum channel strain effect.
- FIG. 1 shows three-dimensional and plan views of a FinFET fin constructed according to some embodiments ( FIG. 1A : all views; FIGS. 1B&E : top view; FIGS. 1C&F : side view; FIGS. 1D&G : end view).
- FIG. 2 shows a TCAD simulation of the off-current density in a p-channel FinFET.
- FIG. 3 shows fin shape, height, and angle ( ) determination for tri-gate transistors.
- the length of the fin is characterized by both a “gate length” defined by the extent of the gate electrode along the long direction of the fin and an “extension length” which comprises additional fin length beyond the gate length toward the source and drain. Typical gate lengths are of similar magnitude to the fin height. FinFETs can also include tri-gate FETs with an angle ⁇ defined as shown in FIG. 3 .
- sidewall spacer refers to an insulating structure adjacent to either end of the gate electrode. Sidewall spacers electrically separate the gate electrode from the source and drain electrodes. For a gate that covers the sides and top of the fin, the sidewall spacers similarly contact the sides and top of the fin.
- a “dummy” gate electrode is formed, for example, from polycrystalline silicon. The sidewall spacers are formed adjacent to the dummy gate electrode. The dummy gate electrode is then removed (etched away), and the actual gate electrode (e.g., metal or metal nitride) is formed between the sidewall spacers.
- lightly doped refers to semiconductor doping levels that are lower than that typically used in most device applications. Typical levels of doping for “lightly doped” semiconductors are 1 to 5 ⁇ 10 15 dopant atoms/cm 3 . However, the doping level can be higher as the channel length is increased.
- the present invention discloses methods of making ultra-low-power FinFETs.
- the methods adapt the concepts used in the super-halo implant methods used with planar FETs to the requirements of the three-dimensional structure of a FinFET by using novel processing steps to achieve similar device performance goals.
- the designs enable higher threshold voltage (V t ) and lower off current (I off ) while maintaining a high I ds sat (or equivalent effective I ds logic operation current.)
- FIG. 1A shows a three-dimensional rendering. Three plan views of a fin (comprising, for example, Si) for a FinFET are also provided.
- FIGS. 1B and 1E show a top view.
- FIGS. 1C and 1F show a side view.
- FIGS. 1D and 1G show an end view.
- the cross section shown is for the plane defined by the lines AA′ and BB′.
- the cross section shown is for the plane defined by the lines CC′ and DD′.
- FIG. 1G the cross section shown is for the plane defined by the lines EE′ and FF′.
- a lightly n-doped fin 100 is formed.
- Fin 100 has a height 2 to 6 times its width, and has two ends, with electrical connection to source 104 and drain 106 which are positioned opposite each end of the fin 100 .
- the fin 100 also has a top and two sides, as shown in FIGS. 1A-1D .
- the fin serves as a “channel” between the source 104 and drain 106 .
- the source (S) 104 and drain (D) 106 comprise p-doped SiGe having Ge>50 atomic %.
- SiGe is a common choice, because it can induce effective compressive channel stress due to lattice mismatch with substrate Si atoms, and a lower junction barrier height that can be caused by a lower energy band gap (E g ) of SiGe compared to Si. Also SiGe can be heavily doped to provide low-resistance connections by using selective epitaxial growth.
- E g energy band gap
- One of ordinary skill will recognize that many other semiconductor materials can be used in source 104 and drain 106 by using lattice mismatch of composite atoms to create stress in the channel.
- a counter-doped (p-doped) region 102 of a few nanometers (e.g., 1-3 nm) thickness is formed on the top and sides of the fin 100 as illustrated in FIGS. 1B , 1 D, 1 E, and 1 G.
- the counter-doped region 102 forms a net neutral (“zero-doped”) surface channel near the high-ic gate dielectric layer (not shown) which surrounds fin 100 , except for the portion underneath the fin which is in contact with the substrate, as shown in the FIGS. 1D and 1G .
- the resulting doping profile (low at the edge—high at the center—low at the edge) yields a low bulk depletion capacitance and lowers the sub-threshold slope of the drain current vs. gate voltage curve.
- Retrograde well formation is not as easily achieved inside such a thin fin by ion implantation as can be implemented in a planar FET.
- a counter doping method can be used. The counter doping creates a relatively higher doping region in the center of the fin compared to the zero doping at the channel surfaces. This counter doping creates a larger depletion depth from the channel edge to the channel center for lower depletion capacitance.
- the lower depletion capacitance reduces a sub-threshold slope that in turn suppresses channel leakage (or channel off) current.
- the FinFET includes angled halo implants 110 (e.g., n-type dopant atoms such as P atoms) formed in the SiGe material of the source and drain adjacent to the ends of the lightly n-doped fin 100 .
- the implant region can be located in the lower part of the channel side of the SiGe p-doped region 108 , i.e., adjacent to the lower portion of the ends of the fin after the sidewall spacers are formed on the fin, as shown in FIGS. 1B , 1 C, 1 E, and 1 F.
- the angled halo implants can be formed by setting the angle for implantation to ⁇ 35-40 degrees.
- Forming diamond-shaped raised S/D regions can provide a deeper set of in situ boron doped SiGe epitaxial S/D.
- the diamond-shaped S/D regions results in lower contact resistance and maximum channel strain.
- a round-shaped embedded SiGe with undercut inside the fin from the S/D ends can reduce the parasitic resistances that exist under the sidewall layers and increases channel strain effectively.
- the halo-implanted region has the effect of raising the source and drain conduction band barrier height by extending the fin semiconductor into the lower part of the source and drain connections to the fin as shown in FIGS. 1C and 1F . This extension can raise threshold voltage (V t ) for a reverse SCE.
- additional halo implants using fluorine atoms can be formed using low energy ion implantation to create band barriers at the edges of the angled halo implants 110 .
- the band barriers can prevent bulk point defects and passivate the halo region to prevent atomic migration.
- the band barriers (not shown in the figures) can be created by halo implantation with a dopant of opposite polarity from that of the S/D regions together with a passivation atom such as fluorine.
- the band barriers can function as diffusion barriers and do not themselves function as either p- or n-type electrical dopants.
- the halo implant ion energy, angle, and a number of ion implants can be adjusted to place these barrier atoms at a desired boundary for the halo-doped region thereby confining the dopant atoms to a well-defined region during any subsequent annealing.
- a typical ion implantation apparatus a single ion beam is available, and the wafer can be positioned and rotated to direct the ion beam to the desired locations.
- a lightly p-doped fin can be formed, having a height of 2-6 times its width, and two ends, with electrical connection to source and drain semiconductor components which are positioned opposite each end of the fin.
- the fin serves as a “channel” between the source and drain.
- the source and drain comprise n-doped S/D for n-channel FinFET.
- a counter-doped (n-doped) region of a few nanometers thickness is formed on the top and sides of the fin. The counter-doped region forms a net neutral (“zero-doped”) surface channel near the high-ic gate dielectric layer (not shown) which surrounds the fin.
- angled halo implants e.g., p-type dopant atoms such as B atoms
- the implant region can be located in the lower part of the channel side of the p-doped region 108 , i.e., adjacent to the lower portion of the ends of the fin after the sidewall spacers are formed on the fin.
- FIG. 2 shows a TCAD (Technology Computer Aided Design) simulation example using Sentaurus tools (all available from Synopsis, Inc., Mountain View Calif.) for a lightly doped fin with a counter-doped layer according to some embodiments of a p-type FinFET.
- a TCAD Technicalnology Computer Aided Design
- Sentaurus tools all available from Synopsis, Inc., Mountain View Calif.
- I off current flows through the center of the fin body (Top View).
- I on current (not shown) normally flows through the fin surface when the channel inversion layer is formed.
- an anti-punch-through (APT) implant might be useful for an extremely short channel FinFET, it would be difficult to directly apply a high dose APT implant into the fin body for prevention of possible fin amorphization. Therefore, in some embodiments, the fin can be modified such that in addition to the intrinsic fin body doping at the channel (fin) surfaces, counter doping with an opposite polarity dopant is provided to form a
- FIG. 3 shows the shape and height of a fin for a tri-gate FinFET, and defines a fin angle (in FIG. 3B ) characterizing the slope of the sidewalls of the fin.
- the FinFET exhibits greater I off and more leakage.
- reduction in the angle ⁇ can also lead to reduced I off .
- embodiments of the present invention include FinFETs having a fin angle of from 6 to 10°.
- FIG. 3A also illustrates the definition of fin height H fin in the presence of shallow trench isolation (STI) 302 .
- the fins are initially formed with a greater height that is effectively reduced by etching back a dielectric material (the STI) to determine the actual fin height.
- the remaining STI partially fills the space for device isolation purposes between fins prior to formation of gate oxide and electrode layers.
- the counter doping can be achieved using wet chemical doping methods.
- Monolayer doping (MLD) methods are described for achieving a very steep S/D junction profile, for example, in Ang et al., (“300 mm FinFET Results Utilizing Conformal, Damage Free, Ultra Shallow Junctions (X j ⁇ 5 nm) Formed with Molecular Monolayer Doping Technique,” IEEE Int. Electron Devices Meeting, 837-40, 2011 incorporated herein by reference).
- monolayer doping can be used for channel counter doping. Briefly, a self-assembled monolayer (SAM) containing dopant atoms is conformally applied to the fin surface, and then the fin and SAM are subsequently heated.
- SAM self-assembled monolayer
- the heating results in the breakage of the molecular structures of the SAM and causes the dopant atoms to migrate into the surface of the fin.
- an oxide capping layer is deposited over the SAM, and RTA at 950-1150° C. causes the SAM to break and the dopant atoms to migrate into the fin. The oxide is then removed by etching to leave the original fin, now with a counter-doped region near the surface.
- MLD can start with hydrogen-terminated or hydride-based passivation on silicon surfaces (e.g., prepared by etching with 0.5% HF).
- the surface can be reacted with the functional group (e.g., allyl or vinyl) of a dopant molecule (see e.g., Ho, J. C., et al. “Controlled nanoscale doping of semiconductors via molecular monolayers,” Nature Materials 7, 62, 2008, incorporated herein by reference).
- Suitable dopant molecules (precursors) for forming dopant-containing SAMs include, for example, allylboronic acid pinacol ester (a boron containing precursor), trioctylphosphine or diethyl 1-propylphosphonate (phosphorous containing precursors).
- the precursors can be applied to the fin dissolved in a suitable solvent, i.e., a solvent in which the precursors are soluble at the desired concentration, and which does not interfere with or compete with the functional group of the precursor for reaction at the semiconductor surface.
- suitable solvents include mesitylene.
- the wet chemical doping can be omitted, and the dopant molecules can be provided in a sacrificial oxide layer applied conformally to the fin surface.
- This oxide layer is similar to the capping layer applied for embodiments of MLD.
- phosphosilicate glass (PSG) and borosilicate glass (BSG) can be used as dopant sources. After the dopants diffuse into the fin, the glass can be etched away.
- ALD can be used to deposit glass layers having precisely controlled thickness and dopant composition. Subsequent RTA to temperatures of 950-1150° C. (for PSG and BSG layers) can allow the dopant atoms to migrate into the fin, after which the oxide layer can be etched away leaving a counter-doped region at the surface of the fin.
- the counter doping can be achieved by a low energy and/or pressure plasma doping (“PD” or “PLAD”).
- PD low energy and/or pressure plasma doping
- PLD low energy and/or pressure plasma doping
- Contacting the fin surface with a plasma including dopant ions can also be an effective means of conformal surface doping.
- Example plasmas include B 2 Cl 3 or BF 3 at a low pressure for conformal doping in a p-channel (or p-type) FinFET.
- the angled halo implant can be combined with fluorine doping (F-doping) to create band barriers to reduce point defects and to tailor and maintain the doping profile during subsequent annealing.
- F-doping can prevent extended lateral diffusion toward the center of the fin body, which can lead to more random dopant fluctuation (RDF) and affect device mismatch.
- RDF random dopant fluctuation
- F-doping can provide a super-sharp halo profile and reduce halo dopant migration by reducing halo dopant diffusivity.
- the same advantage can be extended to halo doping for FinFETs by creating band barriers using angled ion implantation of F ions at the edges of the halo-doped regions (the edges away from the source and drain contacts).
- p-type doping at high dopant concentration can be performed using low pressure plasma doping with suitable precursor gases.
- suitable precursor gases For example, B 2 H 6 /He can be used for p-type S/D junction doping, and Ar/AsH 3 can be used for n-type S/D junction doping, using in situ doping during SiGe epitaxial growth.
- Relatively high percentages of Ge (more than 50%) in the SiGe semiconductor are also found to be advantageous in achieving the desired maximum channel strain effect for p-channel FinFETs.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- High Energy & Nuclear Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Insulated Gate Type Field-Effect Transistor (AREA)
- Thin Film Transistor (AREA)
Abstract
Description
- This application claims priority from U.S. Provisional Patent Application Ser. No. 61/783,294, filed Mar. 14, 2013, the contents of which are incorporated by reference.
- One or more embodiments of the present invention relate to methods of manufacture of semiconductor devices.
- Halo implant methods have been used to improve a short channel effect (SCE) in planar field effect transistors (“FETs”). Typically, an angled halo ion implantation with dopants of opposite polarity from that of the source and drain regions is used to increase the substrate doping adjacent to the source and drain regions of an FET in a way that effectively reduces the extent of the source and drain at the edges and/or under the sidewall spacers but at some depth below the semiconductor substrate surface.
- Compared to the most advanced planar FET devices, a fin-shaped field effect transistor (“FinFET”) provides lower power due to the fully depleted (lightly doped) thin body of the fin and the resulting reduced or reverse SCE with improved drain-induced barrier lowering (DIBL). A FinFET generally has a lightly doped channel and less random dopant fluctuation (RDF) than a planar FET.
- Low power is increasingly important as device size decreases, particularly for radio frequency (RF) analog circuit design and system-on-chip (SoC) applications, because most RF/analog transistors tend to operate in the saturation region for a higher transconductance. However, as yet, FinFETs for analog applications have not been fully optimized for low power operation.
- Auth et al. (“A 22 nm high performance and low-power CMOS technology featuring fully-depleted tri-gate transistors, self-aligned contacts and high density MIM capacitors,” IEEE Symposium on VSLI Technology, 131-32, 2012, incorporated herein by reference) disclose performance parameters for Intel's tri-gate transistor technology now in volume production. Neither these FinFETs nor others in development take advantage of halo or super-halo implants to improve performance. Super-halo methods have so far been used only in planar FETs, as discussed, for example, in Liu et al. (“Fluorine-assisted super-halo for sub-50 nm transistor,” IEEE Electron Device Letters, 24 (3), 180-82, 2003 incorporated herein by reference).
- Methods for making a FinFET are disclosed. A fin is formed on a substrate, wherein the fin has a height between two and six times its width, and a length defining a channel between source and drain ends. The fin comprises a lightly doped semiconductor. A conformal region of counter-doped semiconductor is formed on the surface of the fin. Halo-doped regions are formed by angled ion implantation. The halo-doped regions are disposed in the lower portion of the source and drain and adjacent to the fin. Energy band barriers can be formed at the edges of the halo-doped regions by angled ion implantation.
- In some embodiments, the conformal region of counter-doped semiconductor is formed by wet chemical doping method using a molecular monolayer deposition (MLD) process. A solution comprising the dopant molecules is applied to the fin surface. A sacrificial oxide layer is added, to encapsulates the fin surface with dopant. The dopant atoms can be made to migrate into the surface of the fin by performing a rapid thermal annealing (RTA) at about 950-1150° C. The oxide layer can be removed after annealing.
- In some embodiments the conformal region of counter-doped semiconductor is formed by exposing the fin surface to a plasma comprising dopant atoms.
- In some embodiments the conformal region of counter-doped semiconductor can be formed by forming a conformal oxide layer comprising dopant atoms on the fin surface. The dopant atoms can be made to migrate into the surface of the fin by performing a rapid thermal annealing (RTA) at about 950-1150° C. The oxide layer can be removed after annealing.
- Novel FinFET devices are disclosed having a fin on a substrate, the fin having a height of 2 to 6 times of its width, and a length defining a channel between source and drain ends. The fin comprises a lightly doped conductor. A conformal counter-doped region is disposed on the top and sides of the fin. Halo-doped regions are disposed in the lower portion of the source and drain and adjacent to the sidewall spacers on the fin.
- Band barriers can be disposed at the edges of the halo-doped regions. The band barriers can comprise barrier atoms comprising halo-implant dopants (p- or n-type dopants) with fluorine for point defect reduction as well as to provide a barrier against dopant migration.
- The lightly doped semiconductor can be n-doped, with the counter-doped region p-doped, and the halo-doped regions n-doped for a low power p-channel FinFET. Alternatively, the lightly doped semiconductor can be p-doped, with the counter-doped semiconductor n-doped, and the halo-doped regions p-doped for a low power n-channel FinFET. The lightly doped semiconductor can comprise Si bulk or SOI fins. The semiconductor used for the source and drain connections can comprise p-doped SiGe for p-type FinFETs, where the Ge fraction is greater than 50% by atomic fraction for achieving a maximum channel strain effect.
-
FIG. 1 shows three-dimensional and plan views of a FinFET fin constructed according to some embodiments (FIG. 1A : all views;FIGS. 1B&E : top view;FIGS. 1C&F : side view;FIGS. 1D&G : end view). -
FIG. 2 shows a TCAD simulation of the off-current density in a p-channel FinFET. -
FIG. 3 shows fin shape, height, and angle ( ) determination for tri-gate transistors. - Before the present invention is described in detail, it is to be understood that unless otherwise indicated this invention is not limited to specific semiconductor devices or to specific semiconductor materials. Exemplary embodiments will be described for three-dimensional transistors such as FinFETs made on silicon substrates, but other devices can also be fabricated using the methods disclosed. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
- It must be noted that as used herein and in the claims, the singular forms “a,” “and” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a layer” includes two or more layers, and so forth.
- Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range, and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. Where the modifier “about” or “approximately” is used, the stated quantity can vary by up to 10%. Where the modifier “substantially equal to” is used, the two quantities may vary from each other by no more than 5%.
- The term “FinFET” as used herein refers to a fin-shaped field effect transistor, typically having feature sizes of less than 28 nm, which includes a semiconductor “fin” that extends the semiconductor region between the source and drain above the semiconductor substrate. Fins have a high aspect ratio wherein the height of the fin is 2 to 6 times the width (e.g., fin width=8 nm and fin height=32 nm for 16 nm node bulk-FinFETs), although the aspect ratio can vary depending on processes. The length of the fin is characterized by both a “gate length” defined by the extent of the gate electrode along the long direction of the fin and an “extension length” which comprises additional fin length beyond the gate length toward the source and drain. Typical gate lengths are of similar magnitude to the fin height. FinFETs can also include tri-gate FETs with an angle θ defined as shown in
FIG. 3 . - The term “sidewall spacer” refers to an insulating structure adjacent to either end of the gate electrode. Sidewall spacers electrically separate the gate electrode from the source and drain electrodes. For a gate that covers the sides and top of the fin, the sidewall spacers similarly contact the sides and top of the fin. In a typical manufacturing process sequence, after the fin is formed, a “dummy” gate electrode is formed, for example, from polycrystalline silicon. The sidewall spacers are formed adjacent to the dummy gate electrode. The dummy gate electrode is then removed (etched away), and the actual gate electrode (e.g., metal or metal nitride) is formed between the sidewall spacers.
- The term “lightly doped” as used herein refers to semiconductor doping levels that are lower than that typically used in most device applications. Typical levels of doping for “lightly doped” semiconductors are 1 to 5×1015 dopant atoms/cm3. However, the doping level can be higher as the channel length is increased.
- The present invention discloses methods of making ultra-low-power FinFETs. The methods adapt the concepts used in the super-halo implant methods used with planar FETs to the requirements of the three-dimensional structure of a FinFET by using novel processing steps to achieve similar device performance goals. The designs enable higher threshold voltage (Vt) and lower off current (Ioff) while maintaining a high Ids sat (or equivalent effective Ids logic operation current.)
- Embodiments will be described for p-type FinFETs, although one of skill in the art will recognize that n-type devices can also be made.
FIG. 1A shows a three-dimensional rendering. Three plan views of a fin (comprising, for example, Si) for a FinFET are also provided.FIGS. 1B and 1E show a top view.FIGS. 1C and 1F show a side view.FIGS. 1D and 1G show an end view. InFIG. 1E the cross section shown is for the plane defined by the lines AA′ and BB′. InFIG. 1F the cross section shown is for the plane defined by the lines CC′ and DD′. InFIG. 1G the cross section shown is for the plane defined by the lines EE′ and FF′. - In some embodiments, a lightly n-doped
fin 100 is formed.Fin 100 has a height 2 to 6 times its width, and has two ends, with electrical connection to source 104 and drain 106 which are positioned opposite each end of thefin 100. Thefin 100 also has a top and two sides, as shown inFIGS. 1A-1D . The fin serves as a “channel” between thesource 104 and drain 106. The source (S) 104 and drain (D) 106 comprise p-doped SiGe having Ge>50 atomic %. SiGe is a common choice, because it can induce effective compressive channel stress due to lattice mismatch with substrate Si atoms, and a lower junction barrier height that can be caused by a lower energy band gap (Eg) of SiGe compared to Si. Also SiGe can be heavily doped to provide low-resistance connections by using selective epitaxial growth. One of ordinary skill will recognize that many other semiconductor materials can be used insource 104 and drain 106 by using lattice mismatch of composite atoms to create stress in the channel. - A counter-doped (p-doped)
region 102 of a few nanometers (e.g., 1-3 nm) thickness is formed on the top and sides of thefin 100 as illustrated inFIGS. 1B , 1D, 1E, and 1G. Thecounter-doped region 102 forms a net neutral (“zero-doped”) surface channel near the high-ic gate dielectric layer (not shown) which surroundsfin 100, except for the portion underneath the fin which is in contact with the substrate, as shown in theFIGS. 1D and 1G . The resulting doping profile (low at the edge—high at the center—low at the edge) yields a low bulk depletion capacitance and lowers the sub-threshold slope of the drain current vs. gate voltage curve. Retrograde well formation is not as easily achieved inside such a thin fin by ion implantation as can be implemented in a planar FET. Instead, a counter doping method can be used. The counter doping creates a relatively higher doping region in the center of the fin compared to the zero doping at the channel surfaces. This counter doping creates a larger depletion depth from the channel edge to the channel center for lower depletion capacitance. The lower depletion capacitance reduces a sub-threshold slope that in turn suppresses channel leakage (or channel off) current. - In some embodiments, the FinFET includes angled halo implants 110 (e.g., n-type dopant atoms such as P atoms) formed in the SiGe material of the source and drain adjacent to the ends of the lightly n-doped
fin 100. The implant region can be located in the lower part of the channel side of the SiGe p-dopedregion 108, i.e., adjacent to the lower portion of the ends of the fin after the sidewall spacers are formed on the fin, as shown inFIGS. 1B , 1C, 1E, and 1F. The angled halo implants can be formed by setting the angle for implantation to ˜35-40 degrees. Forming diamond-shaped raised S/D regions can provide a deeper set of in situ boron doped SiGe epitaxial S/D. The diamond-shaped S/D regions results in lower contact resistance and maximum channel strain. In addition, a round-shaped embedded SiGe with undercut inside the fin from the S/D ends can reduce the parasitic resistances that exist under the sidewall layers and increases channel strain effectively. The halo-implanted region has the effect of raising the source and drain conduction band barrier height by extending the fin semiconductor into the lower part of the source and drain connections to the fin as shown inFIGS. 1C and 1F . This extension can raise threshold voltage (Vt) for a reverse SCE. - In some embodiments, additional halo implants using fluorine atoms can be formed using low energy ion implantation to create band barriers at the edges of the
angled halo implants 110. The band barriers can prevent bulk point defects and passivate the halo region to prevent atomic migration. The band barriers (not shown in the figures) can be created by halo implantation with a dopant of opposite polarity from that of the S/D regions together with a passivation atom such as fluorine. The band barriers can function as diffusion barriers and do not themselves function as either p- or n-type electrical dopants. The halo implant ion energy, angle, and a number of ion implants can be adjusted to place these barrier atoms at a desired boundary for the halo-doped region thereby confining the dopant atoms to a well-defined region during any subsequent annealing. In a typical ion implantation apparatus, a single ion beam is available, and the wafer can be positioned and rotated to direct the ion beam to the desired locations. - In some embodiments, the polarity of doping is reversed. For example, a lightly p-doped fin can be formed, having a height of 2-6 times its width, and two ends, with electrical connection to source and drain semiconductor components which are positioned opposite each end of the fin. The fin serves as a “channel” between the source and drain. The source and drain comprise n-doped S/D for n-channel FinFET. A counter-doped (n-doped) region of a few nanometers thickness is formed on the top and sides of the fin. The counter-doped region forms a net neutral (“zero-doped”) surface channel near the high-ic gate dielectric layer (not shown) which surrounds the fin. The resulting doping profile (low at the edge—high at the center—low at the edge) yields a low bulk depletion capacitance and lowers the sub-threshold slope of the drain current vs. gate voltage curve. In addition, angled halo implants (e.g., p-type dopant atoms such as B atoms) can be formed in the material of the source and drain adjacent to the ends of the lightly n-doped fin. The implant region can be located in the lower part of the channel side of the p-doped
region 108, i.e., adjacent to the lower portion of the ends of the fin after the sidewall spacers are formed on the fin. -
FIG. 2 shows a TCAD (Technology Computer Aided Design) simulation example using Sentaurus tools (all available from Synopsis, Inc., Mountain View Calif.) for a lightly doped fin with a counter-doped layer according to some embodiments of a p-type FinFET. It can be seen that most Ioff current flows through the center of the fin body (Top View). However, Ion current (not shown) normally flows through the fin surface when the channel inversion layer is formed. Although an anti-punch-through (APT) implant might be useful for an extremely short channel FinFET, it would be difficult to directly apply a high dose APT implant into the fin body for prevention of possible fin amorphization. Therefore, in some embodiments, the fin can be modified such that in addition to the intrinsic fin body doping at the channel (fin) surfaces, counter doping with an opposite polarity dopant is provided to form a low-high-low doping profile. -
FIG. 3 shows the shape and height of a fin for a tri-gate FinFET, and defines a fin angle (inFIG. 3B ) characterizing the slope of the sidewalls of the fin. As becomes greater, the FinFET exhibits greater Ioff and more leakage. For example, a planar bulk FET having =90° exhibits more leakage than a FinFET, because the channel cannot be fully depleted, while an ideal FinFET having =0° exhibits the least leakage. In the tri-gate fin design, reduction in the angle θ can also lead to reduced Ioff. Accordingly, embodiments of the present invention include FinFETs having a fin angle of from 6 to 10°.FIG. 3A also illustrates the definition of fin height Hfin in the presence of shallow trench isolation (STI) 302. In some embodiments, the fins are initially formed with a greater height that is effectively reduced by etching back a dielectric material (the STI) to determine the actual fin height. The remaining STI partially fills the space for device isolation purposes between fins prior to formation of gate oxide and electrode layers. - In some embodiments, the counter doping can be achieved using wet chemical doping methods. Monolayer doping (MLD) methods are described for achieving a very steep S/D junction profile, for example, in Ang et al., (“300 mm FinFET Results Utilizing Conformal, Damage Free, Ultra Shallow Junctions (Xj˜5 nm) Formed with Molecular Monolayer Doping Technique,” IEEE Int. Electron Devices Meeting, 837-40, 2011 incorporated herein by reference). In embodiments of the instant invention, monolayer doping can be used for channel counter doping. Briefly, a self-assembled monolayer (SAM) containing dopant atoms is conformally applied to the fin surface, and then the fin and SAM are subsequently heated. The heating results in the breakage of the molecular structures of the SAM and causes the dopant atoms to migrate into the surface of the fin. In some embodiments, an oxide capping layer is deposited over the SAM, and RTA at 950-1150° C. causes the SAM to break and the dopant atoms to migrate into the fin. The oxide is then removed by etching to leave the original fin, now with a counter-doped region near the surface.
- For example, MLD can start with hydrogen-terminated or hydride-based passivation on silicon surfaces (e.g., prepared by etching with 0.5% HF). The surface can be reacted with the functional group (e.g., allyl or vinyl) of a dopant molecule (see e.g., Ho, J. C., et al. “Controlled nanoscale doping of semiconductors via molecular monolayers,” Nature Materials 7, 62, 2008, incorporated herein by reference). Suitable dopant molecules (precursors) for forming dopant-containing SAMs include, for example, allylboronic acid pinacol ester (a boron containing precursor), trioctylphosphine or diethyl 1-propylphosphonate (phosphorous containing precursors). The precursors can be applied to the fin dissolved in a suitable solvent, i.e., a solvent in which the precursors are soluble at the desired concentration, and which does not interfere with or compete with the functional group of the precursor for reaction at the semiconductor surface. Typical solvents include mesitylene.
- In some embodiments, the wet chemical doping can be omitted, and the dopant molecules can be provided in a sacrificial oxide layer applied conformally to the fin surface. This oxide layer is similar to the capping layer applied for embodiments of MLD. For example, phosphosilicate glass (PSG) and borosilicate glass (BSG) can be used as dopant sources. After the dopants diffuse into the fin, the glass can be etched away. For example, ALD can be used to deposit glass layers having precisely controlled thickness and dopant composition. Subsequent RTA to temperatures of 950-1150° C. (for PSG and BSG layers) can allow the dopant atoms to migrate into the fin, after which the oxide layer can be etched away leaving a counter-doped region at the surface of the fin.
- In some embodiments, the counter doping can be achieved by a low energy and/or pressure plasma doping (“PD” or “PLAD”). Contacting the fin surface with a plasma including dopant ions can also be an effective means of conformal surface doping. Example plasmas include B2Cl3 or BF3 at a low pressure for conformal doping in a p-channel (or p-type) FinFET.
- The angled halo implant can be combined with fluorine doping (F-doping) to create band barriers to reduce point defects and to tailor and maintain the doping profile during subsequent annealing. F-doping can prevent extended lateral diffusion toward the center of the fin body, which can lead to more random dopant fluctuation (RDF) and affect device mismatch. In the planar technology (Liu et al., op cit.), F-doping can provide a super-sharp halo profile and reduce halo dopant migration by reducing halo dopant diffusivity. The same advantage can be extended to halo doping for FinFETs by creating band barriers using angled ion implantation of F ions at the edges of the halo-doped regions (the edges away from the source and drain contacts).
- In some embodiments, for effective source/drain doping, p-type doping at high dopant concentration can be performed using low pressure plasma doping with suitable precursor gases. For example, B2H6/He can be used for p-type S/D junction doping, and Ar/AsH3 can be used for n-type S/D junction doping, using in situ doping during SiGe epitaxial growth. Relatively high percentages of Ge (more than 50%) in the SiGe semiconductor are also found to be advantageous in achieving the desired maximum channel strain effect for p-channel FinFETs.
- It will be understood that the descriptions of one or more embodiments of the present invention do not limit the various alternative, modified and equivalent embodiments which may be included within the spirit and scope of the present invention as defined by the appended claims. Furthermore, in the detailed description above, numerous specific details are set forth to provide an understanding of various embodiments of the present invention. However, one or more embodiments of the present invention may be practiced without these specific details. In other instances, well known methods, procedures, and components have not been described in detail so as not to unnecessarily obscure aspects of the present embodiments.
Claims (18)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/871,270 US8853008B1 (en) | 2013-03-14 | 2013-07-15 | Counter-doped low-power FinFET |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201361783294P | 2013-03-14 | 2013-03-14 | |
US13/871,270 US8853008B1 (en) | 2013-03-14 | 2013-07-15 | Counter-doped low-power FinFET |
Publications (2)
Publication Number | Publication Date |
---|---|
US20140264492A1 true US20140264492A1 (en) | 2014-09-18 |
US8853008B1 US8853008B1 (en) | 2014-10-07 |
Family
ID=51523670
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/871,270 Expired - Fee Related US8853008B1 (en) | 2013-03-14 | 2013-07-15 | Counter-doped low-power FinFET |
Country Status (1)
Country | Link |
---|---|
US (1) | US8853008B1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140239347A1 (en) * | 2013-02-27 | 2014-08-28 | Taiwan Semiconductor Manufacturing Company, Ltd. | Structure and Method for Defect Passivation To Reduce Junction Leakage For FinFET Device |
US20150187915A1 (en) * | 2013-12-26 | 2015-07-02 | Samsung Electronics Co., Ltd. | Method for fabricating fin type transistor |
US20150228731A1 (en) * | 2014-02-13 | 2015-08-13 | Taiwan Semiconductor Manufacturing Co., Ltd. | Modified channel position to suppress hot carrier injection in finfets |
US20150325686A1 (en) * | 2014-05-08 | 2015-11-12 | Stmicroelectronics, Inc. | Method for fabricating a semiconductor device including fin relaxation, and related structures |
US9583489B1 (en) | 2016-01-08 | 2017-02-28 | International Business Machines Corporation | Solid state diffusion doping for bulk finFET devices |
EP3147951A1 (en) * | 2015-09-25 | 2017-03-29 | Semiconductor Manufacturing International Corporation (Shanghai) | Semiconductor device and related manufacturing method |
US20180261696A1 (en) * | 2015-12-24 | 2018-09-13 | Intel Corporation | Methods of forming doped source/drain contacts and structures formed thereby |
US20190319098A1 (en) * | 2018-04-13 | 2019-10-17 | Taiwan Semiconductor Manufacturing Co., Ltd. | Supportive Layer in Source/Drains of FinFET Devices |
LU101020B1 (en) * | 2018-11-28 | 2020-05-28 | Luxembourg Inst Science & Tech List | Ion-sensitive field effect transistor |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR102284888B1 (en) | 2015-01-15 | 2021-08-02 | 삼성전자주식회사 | Semiconductor device |
US9397161B1 (en) | 2015-02-26 | 2016-07-19 | International Business Machines Corporation | Reduced current leakage semiconductor device |
KR102530671B1 (en) | 2015-12-31 | 2023-05-10 | 삼성전자주식회사 | Method of fabricating the semiconductor device |
US10115723B2 (en) | 2016-06-03 | 2018-10-30 | Qualcomm Incorporated | Complementary metal oxide semiconductor (CMOS) devices employing plasma-doped source/drain structures and related methods |
US9871041B1 (en) | 2016-06-30 | 2018-01-16 | International Business Machines Corporation | Fabrication of vertical doped fins for complementary metal oxide semiconductor field effect transistors |
US9799736B1 (en) | 2016-07-20 | 2017-10-24 | International Business Machines Corporation | High acceptor level doping in silicon germanium |
US10256405B2 (en) | 2017-04-05 | 2019-04-09 | International Business Machines Corporation | Methods for fabricating artificial neural networks (ANN) based on doped semiconductor elements |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8580643B2 (en) * | 2011-08-24 | 2013-11-12 | Globalfoundries Inc. | Threshold voltage adjustment in a Fin transistor by corner implantation |
-
2013
- 2013-07-15 US US13/871,270 patent/US8853008B1/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8580643B2 (en) * | 2011-08-24 | 2013-11-12 | Globalfoundries Inc. | Threshold voltage adjustment in a Fin transistor by corner implantation |
Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140239347A1 (en) * | 2013-02-27 | 2014-08-28 | Taiwan Semiconductor Manufacturing Company, Ltd. | Structure and Method for Defect Passivation To Reduce Junction Leakage For FinFET Device |
US9806176B2 (en) | 2013-02-27 | 2017-10-31 | Taiwan Semiconductor Manufacturing Company, Ltd. | Structure and method for defect passivation to reduce junction leakage for finfet device |
US9184233B2 (en) * | 2013-02-27 | 2015-11-10 | Taiwan Semiconductor Manufacturing Company, Ltd. | Structure and method for defect passivation to reduce junction leakage for finFET device |
US20150187915A1 (en) * | 2013-12-26 | 2015-07-02 | Samsung Electronics Co., Ltd. | Method for fabricating fin type transistor |
US9570561B2 (en) * | 2014-02-13 | 2017-02-14 | Taiwan Semiconductor Manufacturing Co., Ltd. | Modified channel position to suppress hot carrier injection in FinFETs |
US20150228731A1 (en) * | 2014-02-13 | 2015-08-13 | Taiwan Semiconductor Manufacturing Co., Ltd. | Modified channel position to suppress hot carrier injection in finfets |
CN106537554A (en) * | 2014-05-08 | 2017-03-22 | 索泰克公司 | Method for fabricating a semiconductor device including fin relaxation, and related structures |
US9620626B2 (en) * | 2014-05-08 | 2017-04-11 | Soitec | Method for fabricating a semiconductor device including fin relaxation, and related structures |
US20150325686A1 (en) * | 2014-05-08 | 2015-11-12 | Stmicroelectronics, Inc. | Method for fabricating a semiconductor device including fin relaxation, and related structures |
EP3147951A1 (en) * | 2015-09-25 | 2017-03-29 | Semiconductor Manufacturing International Corporation (Shanghai) | Semiconductor device and related manufacturing method |
US9947538B2 (en) | 2015-09-25 | 2018-04-17 | Semiconductor Manufacturing International (Shanghai) Corporation | Semiconductor device manufacturing method including heat treatment |
US11004978B2 (en) | 2015-12-24 | 2021-05-11 | Intel Corporation | Methods of forming doped source/drain contacts and structures formed thereby |
US20180261696A1 (en) * | 2015-12-24 | 2018-09-13 | Intel Corporation | Methods of forming doped source/drain contacts and structures formed thereby |
US10573750B2 (en) * | 2015-12-24 | 2020-02-25 | Intel Corporation | Methods of forming doped source/drain contacts and structures formed thereby |
US9583489B1 (en) | 2016-01-08 | 2017-02-28 | International Business Machines Corporation | Solid state diffusion doping for bulk finFET devices |
US20190319098A1 (en) * | 2018-04-13 | 2019-10-17 | Taiwan Semiconductor Manufacturing Co., Ltd. | Supportive Layer in Source/Drains of FinFET Devices |
US10854715B2 (en) * | 2018-04-13 | 2020-12-01 | Taiwan Semiconductor Manufacturing Co., Ltd. | Supportive layer in source/drains of FinFET devices |
US11476331B2 (en) | 2018-04-13 | 2022-10-18 | Taiwan Semiconductor Manufacturing Co., Ltd. | Supportive layer in source/drains of FinFET devices |
US11855142B2 (en) | 2018-04-13 | 2023-12-26 | Taiwan Semiconductor Manufacturing Co., Ltd. | Supportive layer in source/drains of FinFET devices |
WO2020109110A1 (en) * | 2018-11-28 | 2020-06-04 | Luxembourg Institute Of Science And Technology (List) | Ion-sensitive field effect transistor |
LU101020B1 (en) * | 2018-11-28 | 2020-05-28 | Luxembourg Inst Science & Tech List | Ion-sensitive field effect transistor |
Also Published As
Publication number | Publication date |
---|---|
US8853008B1 (en) | 2014-10-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8853008B1 (en) | Counter-doped low-power FinFET | |
JP4551811B2 (en) | Manufacturing method of semiconductor device | |
US9450078B1 (en) | Forming punch-through stopper regions in finFET devices | |
CN107958873B (en) | Fin type field effect transistor and forming method thereof | |
US9741830B2 (en) | Method for forming metal oxide semiconductor device | |
JP5728444B2 (en) | Semiconductor device and manufacturing method thereof | |
US20110269287A1 (en) | Methods for doping fin field-effect transistors | |
US8759916B2 (en) | Field effect transistor and a method of forming the transistor | |
US8828812B2 (en) | Silicon-germanium heterojunction tunnel field effect transistor and preparation method thereof | |
US9202812B2 (en) | Abrupt source/drain junction formation using a diffusion facilitation layer | |
CN104752211A (en) | Fin type field-effect transistor and forming method thereof | |
CN108538911B (en) | Optimized L-type tunneling field effect transistor and preparation method thereof | |
US20140120677A1 (en) | Methods of forming enhanced mobility channel regions on 3d semiconductor devices, and devices comprising same | |
CN106935505B (en) | The forming method of fin formula field effect transistor | |
CN104425607B (en) | Nodeless mesh body pipe and preparation method thereof | |
CN103515231B (en) | FinFET manufacture method | |
CN103295899B (en) | FinFET manufacture method | |
CN108630542B (en) | Semiconductor structure and forming method thereof | |
US9048123B2 (en) | Interdigitated finFETs | |
CN103123899B (en) | FinFET manufacture method | |
US9502507B1 (en) | Methods of forming strained channel regions on FinFET devices | |
US9508848B1 (en) | Methods of forming strained channel regions on FinFET devices by performing a heating process on a heat-expandable material | |
CN105826374B (en) | P-type fin field effect transistor and forming method thereof | |
TWI782101B (en) | Semiconductor structure and fabrication method thereof | |
CN114256336A (en) | Semiconductor device and manufacturing method thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INTERMOLECULAR, INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LEE, MANKOO;REEL/FRAME:030296/0547 Effective date: 20130425 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551) Year of fee payment: 4 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20221007 |