US20190115445A1 - High Electron Mobility Transistor with Negative Capacitor Gate - Google Patents
High Electron Mobility Transistor with Negative Capacitor Gate Download PDFInfo
- Publication number
- US20190115445A1 US20190115445A1 US15/785,610 US201715785610A US2019115445A1 US 20190115445 A1 US20190115445 A1 US 20190115445A1 US 201715785610 A US201715785610 A US 201715785610A US 2019115445 A1 US2019115445 A1 US 2019115445A1
- Authority
- US
- United States
- Prior art keywords
- layer
- hemt
- cap
- channel
- cap layer
- 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
- 239000003990 capacitor Substances 0.000 title claims description 46
- 239000000463 material Substances 0.000 claims abstract description 50
- 239000004065 semiconductor Substances 0.000 claims abstract description 41
- 229910052751 metal Inorganic materials 0.000 claims abstract description 39
- 239000002184 metal Substances 0.000 claims abstract description 39
- 230000005533 two-dimensional electron gas Effects 0.000 claims abstract description 9
- 230000004044 response Effects 0.000 claims abstract description 6
- 229910002601 GaN Inorganic materials 0.000 claims description 18
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 16
- 238000005229 chemical vapour deposition Methods 0.000 claims description 15
- 238000000151 deposition Methods 0.000 claims description 12
- 230000001419 dependent effect Effects 0.000 claims description 10
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 claims description 8
- 239000000758 substrate Substances 0.000 claims description 8
- 230000004888 barrier function Effects 0.000 claims description 7
- 230000008021 deposition Effects 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- RNQKDQAVIXDKAG-UHFFFAOYSA-N aluminum gallium Chemical compound [Al].[Ga] RNQKDQAVIXDKAG-UHFFFAOYSA-N 0.000 claims description 5
- 229910002113 barium titanate Inorganic materials 0.000 claims description 5
- KQHQLIAOAVMAOW-UHFFFAOYSA-N hafnium(4+) oxygen(2-) zirconium(4+) Chemical compound [O--].[O--].[O--].[O--].[Zr+4].[Hf+4] KQHQLIAOAVMAOW-UHFFFAOYSA-N 0.000 claims description 5
- 238000001465 metallisation Methods 0.000 claims description 5
- AUCDRFABNLOFRE-UHFFFAOYSA-N alumane;indium Chemical compound [AlH3].[In] AUCDRFABNLOFRE-UHFFFAOYSA-N 0.000 claims description 4
- 238000000231 atomic layer deposition Methods 0.000 claims description 4
- 238000001451 molecular beam epitaxy Methods 0.000 claims description 4
- 238000000927 vapour-phase epitaxy Methods 0.000 claims description 4
- 238000005530 etching Methods 0.000 claims description 3
- 230000008020 evaporation Effects 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 3
- 229910000449 hafnium oxide Inorganic materials 0.000 claims description 3
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 238000004544 sputter deposition Methods 0.000 claims description 3
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 claims description 2
- 238000000137 annealing Methods 0.000 claims description 2
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 229910052738 indium Inorganic materials 0.000 claims description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 2
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 claims description 2
- 238000005328 electron beam physical vapour deposition Methods 0.000 claims 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims 1
- AJGDITRVXRPLBY-UHFFFAOYSA-N aluminum indium Chemical compound [Al].[In] AJGDITRVXRPLBY-UHFFFAOYSA-N 0.000 claims 1
- 229910052594 sapphire Inorganic materials 0.000 claims 1
- 239000010980 sapphire Substances 0.000 claims 1
- 229910052710 silicon Inorganic materials 0.000 claims 1
- 239000010703 silicon Substances 0.000 claims 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims 1
- 150000004767 nitrides Chemical class 0.000 description 11
- 230000015556 catabolic process Effects 0.000 description 10
- 230000010287 polarization Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 230000005684 electric field Effects 0.000 description 7
- 238000005259 measurement Methods 0.000 description 5
- 239000002131 composite material Substances 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 3
- 238000001459 lithography Methods 0.000 description 3
- 230000000087 stabilizing effect Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910003781 PbTiO3 Inorganic materials 0.000 description 1
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 229910002370 SrTiO3 Inorganic materials 0.000 description 1
- 239000008186 active pharmaceutical agent Substances 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000609 electron-beam lithography Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
- 150000002739 metals Chemical group 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/78391—Field effect transistors with field effect produced by an insulated gate the gate comprising a layer which is used for its ferroelectric properties
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/51—Insulating materials associated therewith
- H01L29/517—Insulating materials associated therewith the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/401—Multistep manufacturing processes
- H01L29/4011—Multistep manufacturing processes for data storage electrodes
- H01L29/40111—Multistep manufacturing processes for data storage electrodes the electrodes comprising a layer which is used for its ferroelectric properties
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/495—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a simple metal, e.g. W, Mo
- H01L29/4958—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET the conductor material next to the insulator being a simple metal, e.g. W, Mo with a multiple layer structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/66446—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET]
- H01L29/66462—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET] with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/778—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/778—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface
- H01L29/7782—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface with confinement of carriers by at least two heterojunctions, e.g. DHHEMT, quantum well HEMT, DHMODFET
- H01L29/7783—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface with confinement of carriers by at least two heterojunctions, e.g. DHHEMT, quantum well HEMT, DHMODFET using III-V semiconductor material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/778—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface
- H01L29/7786—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. 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
- H01L29/20—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIIBV compounds
- H01L29/2003—Nitride compounds
Definitions
- the present invention relates generally to semiconductor device, and more particularly to high electron mobility transistor suitable for high-power and high frequency applications.
- microwave transistors are playing critical roles in many aspects of human activities.
- JM Johnson Figure of Merit
- GaN can be used to fabricate high electron mobility transistors (HEMTs) whereas SiC can only be used to fabricate metal semiconductor field effect transistors (MESFETs).
- HEMTs high electron mobility transistors
- MESFETs metal semiconductor field effect transistors
- the advantages of the HEMT include its high carrier concentration and its higher electron mobility due to reduced ionized impurity scattering.
- the combination of high carrier concentration and high electron mobility results in a high current density and a low channel resistance, which are especially important for high frequency operation and power switching applications.
- GaN-based HEMTs have many advantages over existing production technologies.
- the high output power density allows the fabrication of much smaller size devices with the same output power.
- Higher impedance due to the smaller size allows for easier and lower loss matching in amplifiers.
- the operation at high voltage due to its high breakdown electric field not only reduces the need for voltage conversion, but also provides the potential to obtain high efficiency, which is a critical parameter for amplifiers.
- the wide bandgap also enables it to operate at high temperatures.
- the HEMT offers better noise performance than that of MESFET's.
- a nitride semiconductor device is used for high-power and high-frequency applications, due to its combination of fundamental physical properties, such as large band gaps, large breakdown fields, and high electron mobility.
- One way to achieve the gain and efficiency requirements at Ka-band and above is to reduce transit time for carriers in the channel region by reducing the gate length.
- Some embodiments are based on recognition that the maximum power that can be taken out from a HEMT depends on two dimensional electron gas (2-DEG) carrier density, the higher the 2-DEG density the higher the output power.
- the 2-DEG density depends on the thickness of the cap layer, i.e. one of the layer of semiconductor material forming the heterojunction in the HEMT. Specifically, a higher cap layer thickness yields higher power and vice versa. However, thicker cap layer reduces the gate capacitance thus the cut off frequencies. Therefore, there is a need for developing a method to increase the cap layer thickness without reducing the gate capacitance.
- Some embodiments are based on realization that if the gate of the HEMT includes and/or acts as a negative capacitor when an electrical pulse is applied to the gate, the negative capacitance can compensate the decrement of the capacitance between the gate and the 2-DEG channel caused by the increase in the thickness of the cap layer. In such a manner, the negative capacitor of the gate allows increasing the thickness of the cap layer beyond a maximum thickness allowed for a target cut-off frequency without consideration for the negative capacitor.
- III-N material can be used for both forming a positive capacitor with the metal of the gate and to form heterojunction with another semiconducting material to form the 2-DEG channel
- III-N material include one or combination of aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum nitride (AlN), gallium nitride (GaN), indium aluminum nitride (InAlN), indium aluminum gallium nitride (InAlGaN).
- the negative capacitor can be realized with the help of ferroelectric oxide (FEO) material.
- FEO ferroelectric oxide
- the FEO material include one or a combination of Barium titanate (BaTiO 3 ), Strontium titanate (SrTiO 3 ), Hafnium Zirconium Oxide (HfZrOx) and Doped Hafnium oxide.
- a layered structure forms the series of positive and negative capacitors when the thickness of the FEO layer is less than t cap /(2 ⁇ cap ), wherein ⁇ is a parameter of the material of the FEO layer, t cap is the thickness of the cap layer, and ⁇ cap is the electric permittivity of the cap layer.
- Parameter a is a constant for given FEO layer, and can be found by performing a polarization measurement as a function of applied voltage.
- a high electron mobility transistor including a semiconductor structure including a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel; and a gate arranged on the cap layer between the source and the drains, such that the conductivity of the 2-DEG channel can be modulated in response to applying voltage to the gate.
- HEMT high electron mobility transistor
- the gate has a layered structure including a bottom metal layer arranged on top of the cap layer, a FEO layer arranged on top of the bottom metal layer, and a top metal layer arranged on top of the FEO layer.
- the thickness of the FEO layer is less than t cap /(2 ⁇ cap ), wherein ⁇ is a parameter of material of the FEO layer, t cap is the thickness of the cap layer, and ⁇ cap is the electric permittivity of the cap layer.
- the cap layer plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have the thickness of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor.
- the thickness of the cap layer is greater than a ratio of a structure dependent constant to the cut-off frequency of the HEMT minus the length of the HEMT.
- the value of the structure dependent constant varies for different semiconductor materials of the HEMT.
- the structure dependent constant can be calculated by fabricating HEMTs with varying channel length and cap layer thickness and measuring the cut off frequency. Once the fabrication and measurement is done, then the constant can be calculated by simply fitting the obtained data.
- the structure dependent constant is 3.9 GHz- ⁇ m for the cap layer including aluminum gallium nitride (AlGaN) material.
- the HEMT is adapted for radio-frequency (RF) applications.
- the mutual geometrical arrangement of the source, the drain, and the gate is selected for amplifying RF signals.
- a distance between the source and the gate of the HEMT is greater than a distance between the gate and the drain.
- SS subthreshold swing
- transconductance is an important factor for the RF applications as the gain and frequency response of the RF HEMT depends on the value of this parameter. The higher value of that transconductance causes the higher value of the gain.
- Some embodiments are based on recognition that for the same cap layer thickness, the HEMT employing principles of various embodiments is capable of providing higher transconductance. To that end, some embodiments select the thickness of the cap layer such that the transconductance of the HEMT is greater than the transconductance of the HEMT without the negative capacitor.
- a high electron mobility transistor including a semiconductor structure which includes a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel; and a gate arranged on the cap layer between the source and the drains, such that the conductivity of the 2-DEG channel is modulated in response to applying voltage to the gate, the gate having a layered structure including a bottom metal layer arranged on top of the cap layer, a ferroelectric oxide (FEO) layer arranged on top of the bottom metal layer, and a top metal layer arranged on top of the FEO layer, wherein the thickness of the FEO layer is less than t cap /(2 ⁇ cap ), wherein ⁇ is a parameter of material of the FEO layer, t cap is the thickness of
- 2-DEG two dimensional electron gas
- HEMT high electron mobility transistor
- a method for manufacturing a high electron mobility transistor including providing a substrate and a semiconductor structure including a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; etching the semiconductor structure to define an active region of the HEMT; forming a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel by metal deposition and annealing; and forming a gate by depositing a bottom metal layer on the cap layer between the source and the drain, depositing a Ferroelectric Oxide (FEO) layer on the bottom metal layer, and depositing a top metal layer on the FEO layer, wherein the thickness of the FEO layer is less than t cap /(2 ⁇ cap ), wherein ⁇ is a parameter of material of the FEO layer, t cap is the thickness of the cap layer, and ⁇
- FIG. 1A shows the 2-D cross section schematic of a composite layer structure according to some embodiments.
- FIG. 1B shows the Polarization vs Electric field curve for an exemplar ferroelectric oxide, i.e., Hafnium Zirconium Oxide (HfZrOx).
- HfZrOx Hafnium Zirconium Oxide
- FIG. 2A shows a plot of the charge voltage characteristics of a positive capacitor formed by a cap layer according to some embodiments.
- FIG. 2B shows a plot of the charge voltage characteristics of a negative capacitor formed by the FEO layer according to some embodiments.
- FIG. 3A shows a plot of the Energy vs Charge characteristics of a positive capacitor formed by a cap layer according to some embodiments.
- FIG. 3B shows a plot of the Energy vs Charge characteristics of a negative capacitor employed by some embodiments.
- FIG. 4 shows a plot of the energy landscape curve of a ferroelectric oxide material as a function of charge used in FEO layer according to some embodiments.
- FIG. 5 shows a 2-D cross section schematic of nitride semiconductor based high electron mobility transistor (HEMT) with ferroelectric oxide as the gate dielectric according to some embodiments.
- HEMT high electron mobility transistor
- FIG. 6 shows a 2-D cross section view of a nitride semiconductor based high electron mobility transistor (HEMT) without negative capacitor.
- HEMT high electron mobility transistor
- FIG. 7 shows simulated drain current vs gate voltage (I DS vs V GS ) characteristics of the HEMT and a negative capacitor gate HEMT (NC-HEMT) of some embodiments.
- FIG. 8 shows a circuit comprising a series combination of a positive capacitor and a negative capacitor formed by some embodiments.
- FIG. 9 shows a plot of transconductance vs gate voltage characteristics of the HEMT and the NC-HEMT of some embodiments.
- FIG. 10 shows a 2-D cross section view of a variant of NC-HEMT according to one embodiment.
- FIG. 11 shows the relative arrangement of source electrode, gate electrode, and drain electrode of a NC-HEMT according to one embodiment.
- FIG. 12 shows a plot of 2-DEG concentration as a function of the thickness in the NC-HEMT of some embodiments.
- FIG. 13 shows the block diagram of a method for fabricating HEMT according to some embodiments.
- FIG. 1 shows the 2-D cross section schematic of a composite layer structure 100 according to some embodiments.
- the layered structure 100 includes a nitride semiconductor based cap layer 101 , a bottom metal layer 102 on top of the cap layer, a ferroelectric oxide (FEO) layer 103 on top of the metal layer 102 and a top metal layer 104 on top of the FEO layer.
- the thickness of the FEO layer 103 is below a critical thickness given by the following expression, t cap /(2 ⁇ cap ), wherein ⁇ is a material based parameter for FEO which can have different values for different FEO, t cap is the thickness of the cap layer, and ⁇ cap is the electric permittivity of the cap layer.
- Parameter a is a constant for given FEO layer, and can be found by performing a polarization measurement as a function of applied voltage.
- FIG. 1B shows the Polarization vs Electric field curve for an exemplar ferroelectric oxide, i.e., Hafnium Zirconium Oxide (HfZrOx), used by some embodiments to determine parameter a.
- the electric labeled in this figure as 120 is known as coercive electric field (E c ) and the polarization at zero electric field labeled by 130 is known as remnant polarization P R .
- E c coercive electric field
- P R remnant polarization
- the FEO layered sandwiched between the two metals form a negative capacitor and by keeping its thickness below the said critical thickness guarantees a stable negative capacitance operation in combination with a nitride semiconductor based cap layer 101 .
- the nitride semiconductor based cap layer 101 can be joined with another semiconductor material to form heterojunction creating two dimensional electron gas (2-DEG) channel
- 2-DEG two dimensional electron gas
- the cap layer 101 plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have the thickness of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor.
- FEO materials are a subgroup of pyroelectric materials in which the spontaneous polarization can be reoriented between “equilibrium” states by applying an electric field. Such materials are able to hold a positive or a negative electric charge, even with no additional voltage applied. Ferroelectrics can also switch polarity, from positive to negative, when an external electric field is applied. These undergo a ferroelectric phase transition characterized by the development of a spontaneous (zero field) polarization, changes in the dielectric constant, and crystal structural changes.
- ferroelectric materials include BaTiO 3 , SrTiO 3 , HfZrO x , Doped Hafnium oxide, PbTiO 3 , PbZr 0.2 Ti 0.8 O 3 and Sr 0.8 Bi 2.2 Ta 2 O 9 , by way of example and not limitation.
- Negative capacitance refers to the (usually) unstable charge-voltage relationship of a ferroelectric material that can be stabilized by combining the ferroelectric material with a capacitor in series.
- the layered structure 100 can be thought of two capacitors connected is series wherein the capacitor formed by the top metal, FEO, and bottom metal operates in the negative capacitance zone.
- the cap layer includes nitride semiconductor of thickness between 2 nm to 250 nm.
- Examples of nitride semiconductor materials include GaN, AlN, AlGaN, InAlN, InAlGaN, and InGaN, by way of example and not limitation.
- FIG. 2A shows a plot of the charge voltage characteristics of a positive capacitor formed by a cap layer 101 according to some embodiments. This plot demonstrates that the charge associated with a positive capacitor increases with the increase of the voltage across the positive capacitor.
- FIG. 2B shows a plot of the charge voltage characteristics of a negative capacitor formed by the FEO layer 103 according to some embodiments. This plot demonstrates that the charge associated with a negative capacitor goes down with the increase of the voltage across the negative capacitor.
- FIG. 3A shows a plot of the Energy vs Charge characteristics of a positive capacitor formed by a cap layer 101 according to some embodiments. This plot has a “V” shaped Energy vs Charge curve (U vs Q). The curvature of U vs Q curve gives the value of capacitance.
- FIG. 3B shows a plot of the Energy vs Charge characteristics of a negative capacitor employed by some embodiments.
- This plot has an inverted/upside down “V” shaped Energy vs Charge curve (U vs Q).
- V Energy vs Charge curve
- the curvature of U vs Q curve gives the value of capacitance.
- such a negative capacitor is unstable without additional assistance and configuration.
- FIG. 4 shows a plot of the energy landscape curve 400 of a ferroelectric oxide material as a function of charge used in FEO layer 103 according to some embodiments.
- the energy landscape curve of a FEO material has “W” shape 400 .
- This curve 400 around zero charge value has negative curvature giving rise to negative capacitance, referred herein as a “negative capacitance zone”.
- a FEO material can't stay in this zone because it has higher energy and end up being either of the two local minima 420 and 430 .
- adding a capacitor in series to have the same charge can make the ferroelectric oxide stable in negative capacitance zone. This is because adding a normal capacitor makes the overall energy of the system lower.
- FIG. 5 shows a 2-D cross section schematic of nitride semiconductor based high electron mobility transistor (HEMT) 500 with ferroelectric oxide as the gate dielectric according to some embodiments.
- the HEMT 500 is also referred herein as a negative capacitance gated HEMT (NC-HEMT).
- the NC-HEMT includes a gate 555 having a composite layered structure formed by a ferroelectric oxide layer 503 sandwiched between the bottom metal layer 502 and top metal layer 504 forming a metal-FEO-metal (M-FEO-M) capacitor placed on top of a cap layer 501 .
- the cap layer includes III-N material. Beneath the 501 layer there is a channel layer 505 . At the interface between the channel layer and the cap layer a two dimensional electron gas (2-DEG) labeled 507 is formed.
- 2-DEG two dimensional electron gas
- a set of electrodes including a source 510 and a drain 520 arranged on the cap layer with electrical connection to the 2-DEG channel 507 .
- the channel layer 505 is grown on a substrate 599 through the help of a buffer layer 588 to provide mechanical support for the device so that all the processing to make the device can be performed.
- the thickness of the FEO layer 503 is less than t cap /(2 ⁇ cap ), wherein ⁇ is a parameter of material of the FEO layer 503 , t cap is the thickness of the cap layer, and ⁇ cap is the electric permittivity of the cap layer.
- the cap layer plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have the thickness 509 of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor.
- the thickness of the cap layer is greater than a ratio of a structure dependent constant to the cut-off frequency of the HEMT minus the length of the HEMT.
- the value of the structure dependent constant varies for different semiconductor materials of the HEMT.
- the structure dependent constant can be calculated by fabricating HEMTs with varying channel length and cap layer thickness and measuring the cut off frequency. Once the fabrication and measurement is done, then the constant can be calculated by simply fitting the obtained data.
- the structure dependent constant is 3.9 GHz- ⁇ m for the cap layer including aluminum gallium nitride (AlGaN) material.
- FIG. 6 shows a 2-D cross section view of a nitride semiconductor based high electron mobility transistor (HEMT) without negative capacitor, wherein a 2-DEG labeled 607 is formed at the interface of a cap layer 601 and a channel layer 602 .
- a source electrode 610 and drain electrode 620 are formed on top of the cap layer 601 wherein the source and the drain metal forms an Ohmic contact with the 2-DEG 607 .
- a gate electrode 630 for modulating the conductance of the 2-DEG channel is also provided wherein the gate metal forms a Schottky contact with the cap layer.
- FIG. 7 shows simulated drain current vs gate voltage (I DS vs V GS ) characteristics of the HEMT 600 and a NC-HEMT 500 .
- I DS vs V GS hafnium zirconium oxide (HfZrOx) ferroelectric oxide has been used.
- I DS -V GS characteristics for different FEO thickness (t FE ) are also presented.
- V GS gate voltage
- NC-HEMT provides higher drain current labeled 702 compared to the conventional HEMT labeled 701 .
- FEO based negative capacitance of NC-HEMT amplifies the overall gate capacitance thus provides higher drain current.
- Another thing to be noted here is that a thicker FEO yields higher drain current for a given gate voltage.
- FIG. 8 shows a circuit comprising a series combination of a positive capacitor 802 and a negative capacitor 801 .
- the total capacitance of this combination can be calculated by the equation in 803 wherein the denominator labeled 804 is less than 1 is the condition labeled 805 is satisfied. Therefore, total capacitance C total is greater than the C Cap , which testifies to the fact that adding a negative capacitor in series with a positive one yields a higher total capacitance.
- FIG. 9 shows a plot of transconductance vs gate voltage (g m vs V gs ) characteristics 901 of the HEMT 600 and characteristics 902 of the NC-HEMT 500 for a number of ferroelectric oxide thickness.
- the plot of FIG. 9 demonstrates that g m of NC-HEMT 500 is higher than the HEMT 600 for a given gate voltage.
- both the HEMTs has the same corresponding device dimensions.
- Transconductance of a transistor is proportional to the gate capacitance, this explains why NC-HEMT provides higher g m compared to the HEMT. Another thing is that a thicker FEO yields higher g m for a given gate voltage.
- FIG. 10 shows a 2-D cross section view of a variant of NC-HEMT according to one embodiment of the invention, wherein the structure includes a back barrier layer 506 between the channel layer and buffer layer.
- the purpose of a back barrier layer is to provide quantum confinement to the 2-DEG formed at the interface of channel and cap layer.
- the back barrier is doped with p-type dopants.
- FIG. 11 shows the relative arrangement of source electrode, gate electrode, and drain electrode of a NC-HEMT according to one embodiment.
- the distance between the source electrode and the gate electrode L SD is higher than the distance between the gate electrode and the drain electrode, L GD .
- L SD should be as low as possible because high L SD increases source resistance which in turn decreases the linearity of the device, but cannot be made very small as it increases the parasitic capacitances which decreases cut off frequency.
- L SD is smaller than 500 nm.
- L GD depends on the break down voltage of the device. Higher break down voltage needs higher L GD .
- L GD also depends on the material property of the semiconductor that would be used to form the channel, a wide band gap material would give higher breakdown voltage at a relatively lower L GD . For example if the breakdown voltage of the device is V BR then a GaN based device
- L GD V BR 100 ⁇ ⁇ V ⁇ ⁇ ⁇ m .
- the break-down voltage of any RF transistor has a direct relation with the maximum RF output power
- the NC-HEMT of FIG. 11 is adapted for radio-frequency (RF) applications.
- RF radio-frequency
- SS subthreshold swing
- transconductance is an important factor for the RF applications as the gain and frequency response of the RF HEMT depends on the value of this parameter. The higher value of that transconductance causes the higher value of the gain.
- FIG. 12 shows a plot of 2-DEG concentration as a function of the thickness of a cap layer wherein the cap layer is formed by AlGaN in the NC-HEMT of some embodiments. It is evident from the plot of FIG. 12 that a thicker cap layer gives higher 2-DEG concentration. 2-DEG concentration is an important parameter for achieving higher power at the output. Therefore, it is desirable to have thicker cap layer so that higher output power is achieved.
- the thicker cap layer reduces the cutoff frequencies because of reduced gate capacitance.
- NC-HEMT allows to increase the cap layer thickness without reducing the gate capacitance by introducing negative capacitance at the gate stack. As mentioned earlier negative capacitance increases the overall capacitance thus compensates for the capacitance that was lost due to thicker cap layer thickness.
- FIG. 13 shows the block diagram of a method for fabricating HEMT according to some embodiments.
- the method includes providing substrate 1310 , making 1320 a semiconductor structure comprising at least a III-N channel layer forming a carrier channel in the semiconductor structure.
- the material of cap-layer has a higher bandgap than the bandgap of material in the III-N channel layer.
- various methods can be adopted for the growth and formation of the cap-layer or channel layer, including but not limited to a Chemical Vapor Deposition (CVD), a Metal-Organic-Chemical-Vapor-Deposition (MOCVD), a Molecular Beam Epitaxy (MBE), a Metal-Organic Vapor Phase Epitaxy (MOVPE) and a Plasma Enhanced Chemical Vapor Deposition (PECVD) and a microwave plasma deposition system.
- CVD Chemical Vapor Deposition
- MOCVD Metal-Organic-Chemical-Vapor-Deposition
- MBE Molecular Beam Epitaxy
- MOVPE Metal-Organic Vapor Phase Epitaxy
- PECVD Plasma Enhanced Chemical Vapor Deposition
- the method also includes 1340 , formation of source and the drain electrode to electrically connect to the carrier channel using one or combination of an ebeam deposition, a joule evaporation, a chemical vapor deposition and a sputtering process. Then the sample is annealed >800° C. in vacuum or N2 environment to form the ohmic contact.
- Further method also includes 1350 , the formation of the metal layer for the gate electrode.
- the formation of this metal layer can be done using Lithography ⁇ Metal Deposition ⁇ Lift-off and/or Metal deposition ⁇ Lithography ⁇ Etching approach.
- the lithography could be performed using, including but not limited to photo-lithography, electron-beam lithography.
- Metal deposition can be done using one or combination of an ebeam deposition, a joule evaporation, a chemical vapor deposition and a sputtering process.
- the metal layer deposit ferroelectric 1360 oxide using one or combination of an atomic layer deposition (ALD), a chemical vapor deposition (CVD), Metal-Organic Chemical Vapor Deposition (MOCVD), a Molecular Beam Epitaxy (MBE), a Metal Organic Vapor Phase Epitaxy (MOVPE), a Plasma Enhanced Chemical Vapor Deposition (PECVD), and a microwave plasma deposition.
- ALD atomic layer deposition
- CVD chemical vapor deposition
- MOCVD Metal-Organic Chemical Vapor Deposition
- MBE Molecular Beam Epitaxy
- MOVPE Metal Organic Vapor Phase Epitaxy
- PECVD Plasma Enhanced Chemical Vapor Deposition
- microwave plasma deposition a microwave plasma deposition
Abstract
Description
- The present invention relates generally to semiconductor device, and more particularly to high electron mobility transistor suitable for high-power and high frequency applications.
- With the recent upsurge of the wireless communication market, microwave transistors are playing critical roles in many aspects of human activities.
- The requirements for the performance of microwave transistors are becoming more and more demanding. In the personal mobile communication applications, next generation cell phones require wider bandwidth and improved efficiency. The development of satellite communications and TV broadcasting requires amplifiers
- operating at higher frequencies (from C band to Ku band, further to Ka band) and higher power to reduce the antenna size of terminal users. The same requirement holds for broadband wireless internet connections as well because of the ever increasing speed or data transmission rate.
- Because of these needs, there has been significant investment in the development of high performance microwave transistors and amplifiers based on Si/SiGe, GaAs, SiC and GaN. The Johnson Figure of Merit (JM) gives the power-frequency limit based solely on material properties and can be used to compare different materials for high frequency and high power applications. The requirement for high power and high frequency requires transistors based on semiconductor materials with both large breakdown voltage and high electron velocity. From this point of view, wide bandgap materials, like GaN and SiC, with higher JM are preferable. The wide bandgap results in higher breakdown voltages because the ultimate breakdown field is the field required for band-to-band impact ionization. Moreover, both have high electron saturation velocities, which allow high frequency operation.
- The ability of GaN to form heterojunctions makes it superior compared to SiC, in spite of having similar breakdown fields and saturation electron velocities. GaN can be used to fabricate high electron mobility transistors (HEMTs) whereas SiC can only be used to fabricate metal semiconductor field effect transistors (MESFETs). The advantages of the HEMT include its high carrier concentration and its higher electron mobility due to reduced ionized impurity scattering. The combination of high carrier concentration and high electron mobility results in a high current density and a low channel resistance, which are especially important for high frequency operation and power switching applications.
- From the amplifier point of view, GaN-based HEMTs have many advantages over existing production technologies. The high output power density allows the fabrication of much smaller size devices with the same output power. Higher impedance due to the smaller size allows for easier and lower loss matching in amplifiers. The operation at high voltage due to its high breakdown electric field not only reduces the need for voltage conversion, but also provides the potential to obtain high efficiency, which is a critical parameter for amplifiers. The wide bandgap also enables it to operate at high temperatures. At the same time, the HEMT offers better noise performance than that of MESFET's. These attractive features in amplifier applications enabled by the superior semiconductor properties make the GaN-based HEMT a very promising candidate for different power applications.
- A lot of research has been conducted to improve linearity and normally on or off behavior of the HEMT. See, e.g., U.S. 20080283870. However, there is also a need to further increase the output power of HEMTs.
- A nitride semiconductor device is used for high-power and high-frequency applications, due to its combination of fundamental physical properties, such as large band gaps, large breakdown fields, and high electron mobility. One way to achieve the gain and efficiency requirements at Ka-band and above is to reduce transit time for carriers in the channel region by reducing the gate length. In order to achieve high power, high frequency and low on resistance suitable for high-power applications, it is desirable to increase the carrier density at the channel formed by the semiconductor device.
- Some embodiments are based on recognition that the maximum power that can be taken out from a HEMT depends on two dimensional electron gas (2-DEG) carrier density, the higher the 2-DEG density the higher the output power. On the other hand, the 2-DEG density depends on the thickness of the cap layer, i.e. one of the layer of semiconductor material forming the heterojunction in the HEMT. Specifically, a higher cap layer thickness yields higher power and vice versa. However, thicker cap layer reduces the gate capacitance thus the cut off frequencies. Therefore, there is a need for developing a method to increase the cap layer thickness without reducing the gate capacitance.
- Some embodiments are based on realization that if the gate of the HEMT includes and/or acts as a negative capacitor when an electrical pulse is applied to the gate, the negative capacitance can compensate the decrement of the capacitance between the gate and the 2-DEG channel caused by the increase in the thickness of the cap layer. In such a manner, the negative capacitor of the gate allows increasing the thickness of the cap layer beyond a maximum thickness allowed for a target cut-off frequency without consideration for the negative capacitor.
- Some embodiments are based on recognition that the negative capacitor is unstable in isolation, but can be stabilized if connected in series with a positive capacitor. Further, after some experiments, some embodiments are based on realization that III-N material can be used for both forming a positive capacitor with the metal of the gate and to form heterojunction with another semiconducting material to form the 2-DEG channel Examples of III-N material include one or combination of aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum nitride (AlN), gallium nitride (GaN), indium aluminum nitride (InAlN), indium aluminum gallium nitride (InAlGaN).
- For example, the negative capacitor can be realized with the help of ferroelectric oxide (FEO) material. Examples of the FEO material include one or a combination of Barium titanate (BaTiO3), Strontium titanate (SrTiO3), Hafnium Zirconium Oxide (HfZrOx) and Doped Hafnium oxide. When a layer of FEO material is sandwiched between two layers of metal and combined with the cap layer that includes III-N material, such a layered structure forms the series of positive and negative capacitors when the thickness of the FEO layer is less than tcap/(2αεcap), wherein α is a parameter of the material of the FEO layer, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer. Parameter a is a constant for given FEO layer, and can be found by performing a polarization measurement as a function of applied voltage.
- Accordingly, one embodiment discloses a high electron mobility transistor (HEMT), including a semiconductor structure including a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel; and a gate arranged on the cap layer between the source and the drains, such that the conductivity of the 2-DEG channel can be modulated in response to applying voltage to the gate.
- The gate has a layered structure including a bottom metal layer arranged on top of the cap layer, a FEO layer arranged on top of the bottom metal layer, and a top metal layer arranged on top of the FEO layer. The thickness of the FEO layer is less than tcap/(2αεcap), wherein α is a parameter of material of the FEO layer, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer.
- In such a manner, the cap layer plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have the thickness of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor.
- For example, in some implementations, the thickness of the cap layer is greater than a ratio of a structure dependent constant to the cut-off frequency of the HEMT minus the length of the HEMT. The value of the structure dependent constant varies for different semiconductor materials of the HEMT. The structure dependent constant can be calculated by fabricating HEMTs with varying channel length and cap layer thickness and measuring the cut off frequency. Once the fabrication and measurement is done, then the constant can be calculated by simply fitting the obtained data. For example, the structure dependent constant is 3.9 GHz-μm for the cap layer including aluminum gallium nitride (AlGaN) material.
- In some embodiments, the HEMT is adapted for radio-frequency (RF) applications. To that end, in some embodiments, the mutual geometrical arrangement of the source, the drain, and the gate is selected for amplifying RF signals. For example, in one implementation, a distance between the source and the gate of the HEMT is greater than a distance between the gate and the drain.
- For RF applications, subthreshold swing (SS) which enables sharp switching of a transistor is less important, because the sharp switching is used to reduce the power dissipated in a micro-processor, which typically is not a problem for the RF applications. However, transconductance is an important factor for the RF applications as the gain and frequency response of the RF HEMT depends on the value of this parameter. The higher value of that transconductance causes the higher value of the gain.
- Some embodiments are based on recognition that for the same cap layer thickness, the HEMT employing principles of various embodiments is capable of providing higher transconductance. To that end, some embodiments select the thickness of the cap layer such that the transconductance of the HEMT is greater than the transconductance of the HEMT without the negative capacitor.
- Accordingly, one embodiments discloses a high electron mobility transistor (HEMT), including a semiconductor structure which includes a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel; and a gate arranged on the cap layer between the source and the drains, such that the conductivity of the 2-DEG channel is modulated in response to applying voltage to the gate, the gate having a layered structure including a bottom metal layer arranged on top of the cap layer, a ferroelectric oxide (FEO) layer arranged on top of the bottom metal layer, and a top metal layer arranged on top of the FEO layer, wherein the thickness of the FEO layer is less than tcap/(2αεcap), wherein α is a parameter of material of the FEO layer, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer.
- Another embodiment discloses a method for manufacturing a high electron mobility transistor (HEMT), including providing a substrate and a semiconductor structure including a channel layer and a cap layer arranged on the channel layer to form a two dimensional electron gas (2-DEG) channel at an interface of the channel layer and the cap layer, wherein the cap layer includes III-N material; etching the semiconductor structure to define an active region of the HEMT; forming a set of electrodes including a source and a drain arranged on the cap layer with electrical connection to the 2-DEG channel by metal deposition and annealing; and forming a gate by depositing a bottom metal layer on the cap layer between the source and the drain, depositing a Ferroelectric Oxide (FEO) layer on the bottom metal layer, and depositing a top metal layer on the FEO layer, wherein the thickness of the FEO layer is less than tcap/(2αεcap), wherein α is a parameter of material of the FEO layer, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer.
-
FIG. 1A shows the 2-D cross section schematic of a composite layer structure according to some embodiments. -
FIG. 1B shows the Polarization vs Electric field curve for an exemplar ferroelectric oxide, i.e., Hafnium Zirconium Oxide (HfZrOx). -
FIG. 2A shows a plot of the charge voltage characteristics of a positive capacitor formed by a cap layer according to some embodiments. -
FIG. 2B shows a plot of the charge voltage characteristics of a negative capacitor formed by the FEO layer according to some embodiments. -
FIG. 3A shows a plot of the Energy vs Charge characteristics of a positive capacitor formed by a cap layer according to some embodiments. -
FIG. 3B shows a plot of the Energy vs Charge characteristics of a negative capacitor employed by some embodiments. -
FIG. 4 shows a plot of the energy landscape curve of a ferroelectric oxide material as a function of charge used in FEO layer according to some embodiments. -
FIG. 5 shows a 2-D cross section schematic of nitride semiconductor based high electron mobility transistor (HEMT) with ferroelectric oxide as the gate dielectric according to some embodiments. -
FIG. 6 shows a 2-D cross section view of a nitride semiconductor based high electron mobility transistor (HEMT) without negative capacitor. -
FIG. 7 shows simulated drain current vs gate voltage (IDS vs VGS) characteristics of the HEMT and a negative capacitor gate HEMT (NC-HEMT) of some embodiments. -
FIG. 8 shows a circuit comprising a series combination of a positive capacitor and a negative capacitor formed by some embodiments. -
FIG. 9 shows a plot of transconductance vs gate voltage characteristics of the HEMT and the NC-HEMT of some embodiments. -
FIG. 10 shows a 2-D cross section view of a variant of NC-HEMT according to one embodiment. -
FIG. 11 shows the relative arrangement of source electrode, gate electrode, and drain electrode of a NC-HEMT according to one embodiment. -
FIG. 12 shows a plot of 2-DEG concentration as a function of the thickness in the NC-HEMT of some embodiments. -
FIG. 13 shows the block diagram of a method for fabricating HEMT according to some embodiments. -
FIG. 1 shows the 2-D cross section schematic of acomposite layer structure 100 according to some embodiments. Thelayered structure 100 includes a nitride semiconductor basedcap layer 101, abottom metal layer 102 on top of the cap layer, a ferroelectric oxide (FEO)layer 103 on top of themetal layer 102 and atop metal layer 104 on top of the FEO layer. The thickness of theFEO layer 103 is below a critical thickness given by the following expression, tcap/(2αεcap), wherein α is a material based parameter for FEO which can have different values for different FEO, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer. Parameter a is a constant for given FEO layer, and can be found by performing a polarization measurement as a function of applied voltage. -
FIG. 1B shows the Polarization vs Electric field curve for an exemplar ferroelectric oxide, i.e., Hafnium Zirconium Oxide (HfZrOx), used by some embodiments to determine parameter a. The electric labeled in this figure as 120 is known as coercive electric field (Ec) and the polarization at zero electric field labeled by 130 is known as remnant polarization PR. Once PR and EC are known from the P-E measurement, the parameter α can be calculated by using the following equation, -
- Referring back to
FIG. 1A , in thecomposite layer structure 100, the FEO layered sandwiched between the two metals form a negative capacitor and by keeping its thickness below the said critical thickness guarantees a stable negative capacitance operation in combination with a nitride semiconductor basedcap layer 101. In addition, the nitride semiconductor basedcap layer 101 can be joined with another semiconductor material to form heterojunction creating two dimensional electron gas (2-DEG) channel In such a manner, thecap layer 101 plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have the thickness of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor. - FEO materials are a subgroup of pyroelectric materials in which the spontaneous polarization can be reoriented between “equilibrium” states by applying an electric field. Such materials are able to hold a positive or a negative electric charge, even with no additional voltage applied. Ferroelectrics can also switch polarity, from positive to negative, when an external electric field is applied. These undergo a ferroelectric phase transition characterized by the development of a spontaneous (zero field) polarization, changes in the dielectric constant, and crystal structural changes. Examples of ferroelectric materials include BaTiO3, SrTiO3, HfZrOx, Doped Hafnium oxide, PbTiO3, PbZr0.2Ti0.8O3 and Sr0.8Bi2.2Ta2O9, by way of example and not limitation.
- Negative capacitance refers to the (usually) unstable charge-voltage relationship of a ferroelectric material that can be stabilized by combining the ferroelectric material with a capacitor in series. The
layered structure 100 can be thought of two capacitors connected is series wherein the capacitor formed by the top metal, FEO, and bottom metal operates in the negative capacitance zone. According to some embodiment the cap layer includes nitride semiconductor of thickness between 2 nm to 250 nm. In some embodiments, a nitride semiconductor material may be used such as BwAlxInyGazN, for example, in which w, x, y and z each have any suitable value between zero and one (inclusive), and w+x+y+z=1. Examples of nitride semiconductor materials include GaN, AlN, AlGaN, InAlN, InAlGaN, and InGaN, by way of example and not limitation. -
FIG. 2A shows a plot of the charge voltage characteristics of a positive capacitor formed by acap layer 101 according to some embodiments. This plot demonstrates that the charge associated with a positive capacitor increases with the increase of the voltage across the positive capacitor. -
FIG. 2B shows a plot of the charge voltage characteristics of a negative capacitor formed by theFEO layer 103 according to some embodiments. This plot demonstrates that the charge associated with a negative capacitor goes down with the increase of the voltage across the negative capacitor. -
FIG. 3A shows a plot of the Energy vs Charge characteristics of a positive capacitor formed by acap layer 101 according to some embodiments. This plot has a “V” shaped Energy vs Charge curve (U vs Q). The curvature of U vs Q curve gives the value of capacitance. -
FIG. 3B shows a plot of the Energy vs Charge characteristics of a negative capacitor employed by some embodiments. This plot has an inverted/upside down “V” shaped Energy vs Charge curve (U vs Q). The curvature of U vs Q curve gives the value of capacitance. However, such a negative capacitor is unstable without additional assistance and configuration. -
FIG. 4 shows a plot of theenergy landscape curve 400 of a ferroelectric oxide material as a function of charge used inFEO layer 103 according to some embodiments. The energy landscape curve of a FEO material has “W”shape 400. Thiscurve 400 around zero charge value has negative curvature giving rise to negative capacitance, referred herein as a “negative capacitance zone”. Normally a FEO material can't stay in this zone because it has higher energy and end up being either of the twolocal minima 420 and 430. However, adding a capacitor in series to have the same charge can make the ferroelectric oxide stable in negative capacitance zone. This is because adding a normal capacitor makes the overall energy of the system lower. -
FIG. 5 shows a 2-D cross section schematic of nitride semiconductor based high electron mobility transistor (HEMT) 500 with ferroelectric oxide as the gate dielectric according to some embodiments. TheHEMT 500 is also referred herein as a negative capacitance gated HEMT (NC-HEMT). - The NC-HEMT includes a
gate 555 having a composite layered structure formed by aferroelectric oxide layer 503 sandwiched between thebottom metal layer 502 andtop metal layer 504 forming a metal-FEO-metal (M-FEO-M) capacitor placed on top of acap layer 501. The cap layer includes III-N material. Beneath the 501 layer there is achannel layer 505. At the interface between the channel layer and the cap layer a two dimensional electron gas (2-DEG) labeled 507 is formed. A set of electrodes including asource 510 and adrain 520 arranged on the cap layer with electrical connection to the 2-DEG channel 507. In some implementations, thechannel layer 505 is grown on asubstrate 599 through the help of abuffer layer 588 to provide mechanical support for the device so that all the processing to make the device can be performed. - The thickness of the
FEO layer 503 is less than tcap/(2αεcap), wherein α is a parameter of material of theFEO layer 503, tcap is the thickness of the cap layer, and εcap is the electric permittivity of the cap layer. The cap layer plays dual role in forming the 2-DEG channel and in stabilizing negative capacitor, which allows some embodiments to have thethickness 509 of the cap layer of the semiconductor structure greater than a maximum thickness allowed for the cut-off frequency of the HEMT without consideration for the negative capacitor. - For example, in some implementations, the thickness of the cap layer is greater than a ratio of a structure dependent constant to the cut-off frequency of the HEMT minus the length of the HEMT. The value of the structure dependent constant varies for different semiconductor materials of the HEMT. The structure dependent constant can be calculated by fabricating HEMTs with varying channel length and cap layer thickness and measuring the cut off frequency. Once the fabrication and measurement is done, then the constant can be calculated by simply fitting the obtained data. For example, the structure dependent constant is 3.9 GHz-μm for the cap layer including aluminum gallium nitride (AlGaN) material.
-
FIG. 6 shows a 2-D cross section view of a nitride semiconductor based high electron mobility transistor (HEMT) without negative capacitor, wherein a 2-DEG labeled 607 is formed at the interface of acap layer 601 and achannel layer 602. Asource electrode 610 anddrain electrode 620 are formed on top of thecap layer 601 wherein the source and the drain metal forms an Ohmic contact with the 2-DEG 607. Agate electrode 630 for modulating the conductance of the 2-DEG channel is also provided wherein the gate metal forms a Schottky contact with the cap layer. -
FIG. 7 shows simulated drain current vs gate voltage (IDS vs VGS) characteristics of theHEMT 600 and a NC-HEMT 500. For this simulation hafnium zirconium oxide (HfZrOx) ferroelectric oxide has been used. IDS-VGS characteristics for different FEO thickness (tFE) are also presented. It is quite evident from the simulation results that for a given gate voltage (VGS) NC-HEMT provides higher drain current labeled 702 compared to the conventional HEMT labeled 701. This result can be understood from the fact that drain current of a HEMT scales with the gate capacitance—a higher gate capacitance yielding a higher drain current and vice versa. FEO based negative capacitance of NC-HEMT amplifies the overall gate capacitance thus provides higher drain current. Another thing to be noted here is that a thicker FEO yields higher drain current for a given gate voltage. -
FIG. 8 shows a circuit comprising a series combination of a positive capacitor 802 and anegative capacitor 801. The total capacitance of this combination can be calculated by the equation in 803 wherein the denominator labeled 804 is less than 1 is the condition labeled 805 is satisfied. Therefore, total capacitance Ctotal is greater than the CCap, which testifies to the fact that adding a negative capacitor in series with a positive one yields a higher total capacitance. -
FIG. 9 shows a plot of transconductance vs gate voltage (gm vs Vgs)characteristics 901 of theHEMT 600 andcharacteristics 902 of the NC-HEMT 500 for a number of ferroelectric oxide thickness. The plot ofFIG. 9 demonstrates that gm of NC-HEMT 500 is higher than theHEMT 600 for a given gate voltage. Here, both the HEMTs has the same corresponding device dimensions. Transconductance of a transistor is proportional to the gate capacitance, this explains why NC-HEMT provides higher gm compared to the HEMT. Another thing is that a thicker FEO yields higher gm for a given gate voltage. -
FIG. 10 shows a 2-D cross section view of a variant of NC-HEMT according to one embodiment of the invention, wherein the structure includes a back barrier layer 506 between the channel layer and buffer layer. The purpose of a back barrier layer is to provide quantum confinement to the 2-DEG formed at the interface of channel and cap layer. According to one embodiment the back barrier is doped with p-type dopants. -
FIG. 11 shows the relative arrangement of source electrode, gate electrode, and drain electrode of a NC-HEMT according to one embodiment. In this embodiment, the distance between the source electrode and the gate electrode LSD is higher than the distance between the gate electrode and the drain electrode, LGD. LSD should be as low as possible because high LSD increases source resistance which in turn decreases the linearity of the device, but cannot be made very small as it increases the parasitic capacitances which decreases cut off frequency. - In some embodiments, LSD is smaller than 500 nm. LGD depends on the break down voltage of the device. Higher break down voltage needs higher LGD. LGD also depends on the material property of the semiconductor that would be used to form the channel, a wide band gap material would give higher breakdown voltage at a relatively lower LGD. For example if the breakdown voltage of the device is VBR then a GaN based device
-
- The break-down voltage of any RF transistor has a direct relation with the maximum RF output power,
-
- Therefore, a high breakdown voltage gives higher output power.
- The NC-HEMT of
FIG. 11 is adapted for radio-frequency (RF) applications. For RF applications, subthreshold swing (SS) which enables sharp switching of a transistor is less important, because the sharp switching is used to reduce the power dissipated in a micro-processor, which typically is not a problem for the RF applications. However, transconductance is an important factor for the RF applications as the gain and frequency response of the RF HEMT depends on the value of this parameter. The higher value of that transconductance causes the higher value of the gain. -
FIG. 12 shows a plot of 2-DEG concentration as a function of the thickness of a cap layer wherein the cap layer is formed by AlGaN in the NC-HEMT of some embodiments. It is evident from the plot ofFIG. 12 that a thicker cap layer gives higher 2-DEG concentration. 2-DEG concentration is an important parameter for achieving higher power at the output. Therefore, it is desirable to have thicker cap layer so that higher output power is achieved. The thicker cap layer reduces the cutoff frequencies because of reduced gate capacitance. However, NC-HEMT allows to increase the cap layer thickness without reducing the gate capacitance by introducing negative capacitance at the gate stack. As mentioned earlier negative capacitance increases the overall capacitance thus compensates for the capacitance that was lost due to thicker cap layer thickness. -
FIG. 13 shows the block diagram of a method for fabricating HEMT according to some embodiments. The method includes providingsubstrate 1310, making 1320 a semiconductor structure comprising at least a III-N channel layer forming a carrier channel in the semiconductor structure. The material of cap-layer has a higher bandgap than the bandgap of material in the III-N channel layer. According to some embodiments, various methods can be adopted for the growth and formation of the cap-layer or channel layer, including but not limited to a Chemical Vapor Deposition (CVD), a Metal-Organic-Chemical-Vapor-Deposition (MOCVD), a Molecular Beam Epitaxy (MBE), a Metal-Organic Vapor Phase Epitaxy (MOVPE) and a Plasma Enhanced Chemical Vapor Deposition (PECVD) and a microwave plasma deposition system. - Defining the active region of the transistor by wet etching or
dry etching 1330. Further the method also includes 1340, formation of source and the drain electrode to electrically connect to the carrier channel using one or combination of an ebeam deposition, a joule evaporation, a chemical vapor deposition and a sputtering process. Then the sample is annealed >800° C. in vacuum or N2 environment to form the ohmic contact. - Further method also includes 1350, the formation of the metal layer for the gate electrode. The formation of this metal layer can be done using Lithography→Metal Deposition→Lift-off and/or Metal deposition→Lithography→Etching approach. Here the lithography could be performed using, including but not limited to photo-lithography, electron-beam lithography. Metal deposition can be done using one or combination of an ebeam deposition, a joule evaporation, a chemical vapor deposition and a sputtering process.
- After the formation of the metal layer deposit ferroelectric, 1360 oxide using one or combination of an atomic layer deposition (ALD), a chemical vapor deposition (CVD), Metal-Organic Chemical Vapor Deposition (MOCVD), a Molecular Beam Epitaxy (MBE), a Metal Organic Vapor Phase Epitaxy (MOVPE), a Plasma Enhanced Chemical Vapor Deposition (PECVD), and a microwave plasma deposition. Formation of the
top metal layer 1370 can be performed in a manner similar to formation of thebottom metal layer 1340. - Although the invention has been described by way of examples of preferred embodiments, it is to be understood that various other adaptations and modifications can be made within the spirit and scope of the invention. Therefore, it is the objective of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the invention.
Claims (20)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/785,610 US10276704B1 (en) | 2017-10-17 | 2017-10-17 | High electron mobility transistor with negative capacitor gate |
PCT/JP2018/014830 WO2019077782A1 (en) | 2017-10-17 | 2018-03-30 | High electron mobility transistor with negative capacitor gate |
JP2019572240A JP6789422B2 (en) | 2017-10-17 | 2018-03-30 | High electron mobility transistor with negative capacitor gate |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/785,610 US10276704B1 (en) | 2017-10-17 | 2017-10-17 | High electron mobility transistor with negative capacitor gate |
Publications (2)
Publication Number | Publication Date |
---|---|
US20190115445A1 true US20190115445A1 (en) | 2019-04-18 |
US10276704B1 US10276704B1 (en) | 2019-04-30 |
Family
ID=62116520
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/785,610 Active US10276704B1 (en) | 2017-10-17 | 2017-10-17 | High electron mobility transistor with negative capacitor gate |
Country Status (3)
Country | Link |
---|---|
US (1) | US10276704B1 (en) |
JP (1) | JP6789422B2 (en) |
WO (1) | WO2019077782A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190288116A1 (en) * | 2018-03-15 | 2019-09-19 | SK Hynix Inc. | Ferroelectric memory device |
US20210391471A1 (en) * | 2020-06-15 | 2021-12-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Semiconductor device and method of fabricating the same |
DE102021201791A1 (en) | 2021-02-25 | 2022-08-25 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung eingetragener Verein | High Electron Mobility Transistor (HEMT), Transistor Assembly, Method of Controlling a HEMT, and Method of Making a HEMT |
KR20220128601A (en) * | 2019-06-25 | 2022-09-21 | 한양대학교 에리카산학협력단 | Negative capacitance transistor and fabricating method |
CN115259294A (en) * | 2022-08-08 | 2022-11-01 | 华北电力科学研究院有限责任公司 | Water body pH adjusting device and method |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11315951B2 (en) * | 2019-11-11 | 2022-04-26 | Electronics And Telecommunications Research Institute | Semiconductor device and method of fabricating the same |
CN111884593B (en) * | 2020-08-04 | 2021-04-20 | 重庆邮电大学 | Ring-shaped opening terahertz amplitude modulator based on HEMT and manufacturing method |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150144953A1 (en) * | 2013-11-26 | 2015-05-28 | Darrell G. Hill | Transistors with field plates resistant to field plate material migration and methods of their fabrication |
US20150214352A1 (en) * | 2014-01-28 | 2015-07-30 | Infineon Technologies Austria Ag | Enhancement Mode Device |
US20150357457A1 (en) * | 2014-06-06 | 2015-12-10 | Rf Micro Devices, Inc. | Schottky gated transistor with interfacial layer |
US9396946B2 (en) * | 2011-06-27 | 2016-07-19 | Cree, Inc. | Wet chemistry processes for fabricating a semiconductor device with increased channel mobility |
US20160308021A1 (en) * | 2014-04-04 | 2016-10-20 | Taiwan Semiconductor Manufacturing Company, Ltd. | Tunnel MOSFET with Ferroelectric Gate Stack |
US20160365435A1 (en) * | 2014-03-25 | 2016-12-15 | Han Wui Then | Iii-n transistors with epitaxial layers providing steep subthreshold swing |
US20160373106A1 (en) * | 2015-06-16 | 2016-12-22 | Tagore Technology, Inc. | High performance radio frequency switch |
US20170084730A1 (en) * | 2009-10-30 | 2017-03-23 | Alpha and Omaga Semiconductor Incorporated | Normally off gallium nitride field effect transistors (fet) |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7230284B2 (en) | 2001-07-24 | 2007-06-12 | Cree, Inc. | Insulating gate AlGaN/GaN HEMT |
US7853235B2 (en) | 2004-02-11 | 2010-12-14 | Qualcomm, Incorporated | Field effect transistor amplifier with linearization |
US7161194B2 (en) | 2004-12-06 | 2007-01-09 | Cree, Inc. | High power density and/or linearity transistors |
US7692263B2 (en) | 2006-11-21 | 2010-04-06 | Cree, Inc. | High voltage GaN transistors |
JP5397825B2 (en) | 2007-05-18 | 2014-01-22 | サンケン電気株式会社 | Field effect semiconductor device |
US8362604B2 (en) | 2008-12-04 | 2013-01-29 | Ecole Polytechnique Federale De Lausanne (Epfl) | Ferroelectric tunnel FET switch and memory |
JP2012049170A (en) | 2010-08-24 | 2012-03-08 | New Japan Radio Co Ltd | Nitride semiconductor device |
US9755059B2 (en) | 2013-06-09 | 2017-09-05 | Cree, Inc. | Cascode structures with GaN cap layers |
US9711616B2 (en) | 2014-12-23 | 2017-07-18 | Northrop Grumman Systems Corporation | Dual-channel field effect transistor device having increased amplifier linearity |
US9673311B1 (en) | 2016-06-14 | 2017-06-06 | Semiconductor Components Industries, Llc | Electronic device including a multiple channel HEMT |
-
2017
- 2017-10-17 US US15/785,610 patent/US10276704B1/en active Active
-
2018
- 2018-03-30 JP JP2019572240A patent/JP6789422B2/en active Active
- 2018-03-30 WO PCT/JP2018/014830 patent/WO2019077782A1/en active Application Filing
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170084730A1 (en) * | 2009-10-30 | 2017-03-23 | Alpha and Omaga Semiconductor Incorporated | Normally off gallium nitride field effect transistors (fet) |
US9396946B2 (en) * | 2011-06-27 | 2016-07-19 | Cree, Inc. | Wet chemistry processes for fabricating a semiconductor device with increased channel mobility |
US20150144953A1 (en) * | 2013-11-26 | 2015-05-28 | Darrell G. Hill | Transistors with field plates resistant to field plate material migration and methods of their fabrication |
US20150214352A1 (en) * | 2014-01-28 | 2015-07-30 | Infineon Technologies Austria Ag | Enhancement Mode Device |
US20160365435A1 (en) * | 2014-03-25 | 2016-12-15 | Han Wui Then | Iii-n transistors with epitaxial layers providing steep subthreshold swing |
US20160308021A1 (en) * | 2014-04-04 | 2016-10-20 | Taiwan Semiconductor Manufacturing Company, Ltd. | Tunnel MOSFET with Ferroelectric Gate Stack |
US20150357457A1 (en) * | 2014-06-06 | 2015-12-10 | Rf Micro Devices, Inc. | Schottky gated transistor with interfacial layer |
US20160373106A1 (en) * | 2015-06-16 | 2016-12-22 | Tagore Technology, Inc. | High performance radio frequency switch |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190288116A1 (en) * | 2018-03-15 | 2019-09-19 | SK Hynix Inc. | Ferroelectric memory device |
US11508846B2 (en) | 2018-03-15 | 2022-11-22 | SK Hynix Inc. | Ferroelectric memory device |
KR20220128601A (en) * | 2019-06-25 | 2022-09-21 | 한양대학교 에리카산학협력단 | Negative capacitance transistor and fabricating method |
KR102620854B1 (en) * | 2019-06-25 | 2024-01-03 | 한양대학교 에리카산학협력단 | Negative capacitance transistor and fabricating method |
US20210391471A1 (en) * | 2020-06-15 | 2021-12-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Semiconductor device and method of fabricating the same |
US11569382B2 (en) * | 2020-06-15 | 2023-01-31 | Taiwan Semiconductor Manufacturing Company, Ltd. | Semiconductor device and method of fabricating the same |
US11901451B2 (en) * | 2020-06-15 | 2024-02-13 | Taiwan Semiconductor Manufacturing Company, Ltd. | Method of fabricating semiconductor device |
DE102021201791A1 (en) | 2021-02-25 | 2022-08-25 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung eingetragener Verein | High Electron Mobility Transistor (HEMT), Transistor Assembly, Method of Controlling a HEMT, and Method of Making a HEMT |
WO2022180127A1 (en) | 2021-02-25 | 2022-09-01 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | High electron mobility transistor (hemt), transistor arrangement, method of controlling an hemt and method of producing an hemt |
CN115259294A (en) * | 2022-08-08 | 2022-11-01 | 华北电力科学研究院有限责任公司 | Water body pH adjusting device and method |
Also Published As
Publication number | Publication date |
---|---|
JP2020526033A (en) | 2020-08-27 |
US10276704B1 (en) | 2019-04-30 |
JP6789422B2 (en) | 2020-11-25 |
WO2019077782A1 (en) | 2019-04-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10276704B1 (en) | High electron mobility transistor with negative capacitor gate | |
US7696535B2 (en) | Gallium nitride high electron mobility transistor having inner field-plate for high power applications | |
KR101359767B1 (en) | High efficiency and/or high power density wide bandgap transistors | |
US7525130B2 (en) | Polarization-doped field effect transistors (POLFETS) and materials and methods for making the same | |
US8338871B2 (en) | Field effect transistor with electric field and space-charge control contact | |
US20040155260A1 (en) | High electron mobility devices | |
US10910480B2 (en) | Transistor with multi-metal gate | |
TW200406065A (en) | Ga/A1Gan heterostructure field effect transistor with dielectric recessed gate | |
JP2013089970A (en) | Group iii metal nitride-insulator semiconductor heterostructure field effect transistor | |
KR20140110615A (en) | Nitride based semiconductor device | |
US10283598B2 (en) | III-V heterojunction field effect transistor | |
EP3491672B1 (en) | High electron mobility transistor with tunable threshold voltage | |
Hao et al. | Research on GaN-Based RF devices: high-frequency gate structure design, submicrometer-length gate fabrication, suppressed SCE, low parasitic resistance, minimized current collapse, and lower gate leakage | |
JP2023503882A (en) | Semiconductors with improved thermal budgets and processes for making semiconductors with improved thermal budgets | |
TW201513345A (en) | Linear high-electron mobility transistor | |
US20230197841A1 (en) | Group iii-nitride high-electron mobility transistors with a buried conductive material layer and process for making the same | |
US20220367695A1 (en) | Circuits and group iii-nitride transistors with buried p-layers and controlled gate voltages and methods thereof | |
Peng et al. | Effects of the Fe-doped GaN buffer in AlGaN/GaN HEMTs on SiC substrate | |
Liu et al. | An extrinsic fmax> 100 GHz InAlN/GaN HEMT with AlGaN back barrier | |
Dubey et al. | Analysis of AlGaN/GaN Based HEMT for Millimeter-Wave Applications | |
Panda et al. | Metal oxide semiconductor high electron mobility transistors | |
TWI446532B (en) | A structure of high electron mobility transistor, a device comprising the structure and a metnod of producing the same | |
Liu et al. | Millimeter-Wave AlGaN/GaN MIS-HEMTs with Multiple T-Gate Technology | |
Ye | III-Nitride Based High Electron Mobility Transistors for RF Applications | |
Lu et al. | High-performance Thin-barrier InGaN Channel DH-HEMT for Millimeter Wave Applications |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: SURCHARGE FOR LATE PAYMENT, LARGE ENTITY (ORIGINAL EVENT CODE: M1554); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |