This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0158042, filed on Nov. 16, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
Some example embodiments relate to a semiconductor device and/or a semiconductor apparatus including the semiconductor device.
Ferroelectrics are materials with ferroelectricity that maintain spontaneous polarization by aligning internal electric dipole moments even when no external electric field is applied thereto. Research has been made to improve the performance of a semiconductor device by applying such a ferroelectric to the semiconductor device.
Provided is a semiconductor device and/or a semiconductor apparatus including the semiconductor device.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, and/or may be learned by practice of the various example embodiments.
According to some example embodiments, a semiconductor device includes a substrate having a channel layer in or on the substrate and including a dopant, a ferroelectric layer on the channel layer, and a gate on the ferroelectric layer. The channel layer may have a doping concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1021 cm−3.
The channel layer may be in an upper portion of the substrate integrally with the substrate, and a source and a drain may be at opposite sides of the channel layer.
The channel layer may be at least partially on the substrate separate from the substrate, and a source and a drain may be at opposite sides of the channel layer.
The channel layer may include at least one of Si, Ge, SiGe, a group III-V semiconductor, an oxide semiconductor, a nitride semiconductor, an oxynitride semiconductor, a two-dimensional (2D) semiconductor material, quantum dots, or an organic semiconductor.
A dopant included in the channel layer may include at least one of a group III element or a group V element.
The channel layer may have a doping concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1018 cm−3.
The ferroelectric layer may include one or more of a fluorite-based material or a perovskite-based material. The ferroelectric layer may include at least one of a hafnium oxide, a zirconium oxide, or a hafnium-zirconium oxide. The ferroelectric layer may further include a dopant of at least one of Si, Al, La, Y, Sr, or Gd.
The semiconductor device may further include a paraelectric layer between the channel layer and the ferroelectric layer. The paraelectric layer may include at least one of a silicon oxide, a silicon nitride, an aluminum oxide, a silicon oxynitride, a lanthanum oxide, or an yttrium oxide.
The channel layer may have one or more of a sheet channel structure, a fin channel structure, or a gate-all-around channel structure.
The gate may include a metal, a metal nitride, polysilicon, or a 2D conductive material.
According to some example embodiments, a semiconductor apparatus includes a field effect transistor, and a capacitor electrically connected to the field effect transistor. The field effect transistor includes a substrate having a channel layer in or on the substrate and including a dopant, a ferroelectric layer on the channel layer, and a gate on the ferroelectric layer. The channel layer may have a doping concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1021 cm−3.
The channel layer may be in an upper portion of the substrate integrally with the substrate, and a source and a drain may be provided at opposite sides of the channel layer.
The channel layer may be at least partially on the substrate separate from the substrate, and a source and a drain may be at opposite sides of the channel layer.
The channel layer may include at least one of Si, Ge, SiGe, a group III-V semiconductor, an oxide semiconductor, a nitride semiconductor, an oxynitride semiconductor, a 2D semiconductor material, quantum dots, or an organic semiconductor.
The channel layer may have a doping concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1018 cm−3.
The ferroelectric layer may include one or more of a fluorite-based material or perovskite. The ferroelectric layer may include at least one of a hafnium oxide, a zirconium oxide, or a hafnium-zirconium oxide. The ferroelectric layer may further include a dopant of at least one of Si, Al, La, Y, Sr, or Gd.
The field effect transistor may further include a paraelectric layer between the channel layer and the ferroelectric layer. The paraelectric layer may include at least one of a silicon oxide, a silicon nitride, an aluminum oxide, a silicon oxynitride, a lanthanum oxide, or an yttrium oxide.
The gate may include a metal, a metal nitride, polysilicon, or a 2D conductive material.
According to some example embodiments, an electronic apparatus includes the above-described semiconductor apparatus.
According to various example embodiments, a semiconductor device may include a channel layer comprising dopants at a concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1021 cm−3, and a ferroelectric layer on the channel layer.
The semiconductor device may further include a substrate, the channel layer integral in the substrate, and a source and a drain, the source and the drain integral with the substrate and at opposite ends of the channel layer.
The source and the drain may include first dopants of a first conductivity type opposite to a conductivity type of second dopants in the channel layer.
According to some example embodiments, a method of fabricating the semiconductor device may include provisioning the substrate, forming the channel layer by implanting the substrate with the second dopants at a first dose, forming the ferroelectric layer on the channel layer, and forming the source and the drain by implanting the substrate with the first dopants at a second dose.
The forming the source and drain regions may be performed after the forming the ferroelectric layer.
The above and other aspects, features, and/or advantages of certain example embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to various example embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, example embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
Hereinafter, various example embodiments will be described in detail with reference to the accompanying drawings. In the drawings below, like reference numbers denote like constituent elements, and the sizes of components in the drawings may be exaggerated for convenience of explanation. Various embodiments described below are merely examples, and various modifications and changes are available from the embodiments.
When a constituent element is disposed “above” or “on” to another constituent element, the constituent element may include not only an element directly contacting on the upper/lower/left/right sides of the other constituent element, but also an element disposed above/under/left/right the other constituent element in a non-contact manner. An expression used in a singular form in the specification also includes the expression in its plural form unless clearly specified otherwise in context. When a part may “include” a certain constituent element, unless specified otherwise, it may not be construed to exclude another constituent element but may be construed to further include other constituent elements.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure are to be construed to cover both the singular and the plural. Also, the steps of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The disclosure is not limited to the described order of the steps.
Furthermore, terms such as “. . . portion,” “. . . unit,” “. . . module,” and “. . . block” stated in the specification may signify a unit to process at least one function or operation and the unit may be embodied by hardware, software, or a combination of hardware and software.
Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent functional relationships and/or physical and/or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections and/or logical connections may be present in a practical device.
The use of any and all examples, or language, e.g., “such as,” provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed.
Referring to
A channel layer 115 is integrally formed or integrally be part of or positioned at or near an upper portion of the substrate 110. The channel layer 115 is provided in the upper portion of the substrate 110 corresponding to the gate 150, and a source 121 and a drain 122 may be provided at opposite sides of the channel layer 115.
The source 121 may be electrically connected to one side of the channel layer 115, and the drain 122 may be electrically connected to the other side of the channel layer 115. The source and drain 121 and 122 may be formed by doping or implant, e.g. injecting, impurities into different regions of the substrate 110, and a region of the substrate 110 between the source 121 and the drain 122 may be defined as the channel layer 115. Accordingly, the channel layer 115 may be provided integrally with or within the substrate 110. However, as described below, a channel layer may be provided as a material layer separate from or at least partially separate from the substrate 110, not as a part of or included in the substrate 110.
The substrate 110 including the channel layer 115 may include a semiconductor material. For example, the substrate 110 may include, for example, one or more of Si, Ge, SiGe, a group III-V semiconductor, and the like. The substrate 110 may be formed from a Czochralski substrate and may be doped, e.g. may be lightly doped with one or more of boron, phosphorus, or arsenic during the Czochralski process; however, example embodiments are not limited thereto, and the substrate 110 may be initially undoped. Furthermore, the substrate 110 may include at least one of, for example, an oxide semiconductor, a nitride semiconductor, an oxynitride semiconductor, a two-dimensional (2D) semiconductor material, quantum dots, or an organic semiconductor. The oxide semiconductor may include, for example, InGaZnO and the like, the 2D semiconductor material may include, for example, transition metal dichalcogenide (TMD) or graphene, and the quantum dots may include colloidal quantum dots, a nanocrystal structure, and the like. However, this is merely an example, and example embodiments are not limited thereto.
The substrate 110 including the channel layer 115 may include a dopant of a certain concentration. The dopant may include a p-type dopant or an n-type dopant. The p-type dopant may include, for example, a group III element such as B, Al, Ga, In, and the like, and the n-type dopant may include, for example, a group V element such as P, As, Sb, and the like.
A semiconductor substrate including the p-type dopant at a particular dopant concentration in the channel layer 115 may be used as or for the substrate 110, and when the source and drain 121 and 122 include n-type impurities, the semiconductor device 100 having an NMOS structure may be implemented. A semiconductor substrate including the n-type dopant at a particular dopant concentration in the channel layer 115 may be used as the substrate 110, and when the source and drain 121 and 122 include p-type impurities, the semiconductor device 100 having a PMOS structure may be implemented.
In the semiconductor device 100 according to various example embodiments, the substrate 110 including the channel layer 115 may have a doping concentration of, for example, 1×1015 cm−3 to 1×1021 cm−3 within the channel layer 115. As a detailed example, the substrate 110 including the channel layer 115 may have a doping concentration within the channel layer of 1×1015 cm−3 to 1×1021 cm−3. More specifically, the channel layer may have a doping concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1018 cm−3.
The ferroelectric layer 140 is provided on the channel layer 115 of the substrate 110. A ferroelectric has a spontaneous dipole (electric dipole), for example, spontaneous polarization, because an electric charge distribution in a unit cell is non-centrosymmetric in a crystallized material structure. Furthermore, the ferroelectric has remnant polarization by a dipole when there is no external electric field. In the ferroelectric, the direction of polarization may be switched to a domain unit by an external electric field.
The ferroelectric layer 140 may include, for example, a fluorite-based material and/or a perovskite based material, and the like. The perovskite material may include, for example, PZT, BaTiO3, PbTiO3, and the like. The fluorite-based material may include, for example, at least one oxide selected from among Hf, Si, Al, Zr, Y, La, Gd, and Sr.
As a detailed example, the ferroelectric layer 140 may include at least one of a hafnium oxide (HfO), a zirconium oxide (ZrO), or a hafnium-zirconium oxide (HfZrO). The hafnium oxide (HfO), the zirconium oxide (ZrO), and the hafnium-zirconium oxide (HfZrO) constituting or included in the ferroelectric layer 140 may have a crystal structure of an orthorhombic crystal system. The ferroelectric layer 140 may further include a dopant of, for example, at least one of Si, Al, La, Y, Sr, or Gd. However, the materials stated below are merely an example, and various other materials may be used as the ferroelectric layer 140.
The paraelectric layer 130 may be provided between the channel layer 115 of the substrate 110 and the ferroelectric layer 140. The paraelectric layer 130 may include, for example, at least one of a silicon oxide, a silicon nitride, an aluminum oxide, a silicon oxynitride, a lanthanum oxide, or an yttrium oxide. However, example embodiments are not limited thereto.
The gate 150 is provided on the ferroelectric layer 140. The gate 150 may be arranged facing the channel layer 115 of the substrate 110. The gate 150 may include, for example, a conductive material such as one or more of a metal, a metal nitride, polysilicon such as doped polysilicon, a 2D conductive material, and the like.
In the semiconductor device 100 according to various example embodiments, as the ferroelectric layer 140 is formed between the channel layer 115 and the gate 150, subthreshold swing (SS) of the semiconductor device 100 may be reduced by voltage amplification according to a negative capacitance effect.
Referring to
In a ferroelectric semiconductor device, when the doping concentration of a channel layer increases, remnant polarization Pr and coercive voltage Vc increase, and in this case, the degradation of a ferroelectric may be accelerated occurring, for example, from repeated cycles of programming and erasing. In the semiconductor device 100 according to various example embodiments, by having a lower doping concentration of a channel layer from 1×1015 cm−3 to 1×1021 cm−3 compared with the doping concentration of the existing ferroelectric semiconductor device, the remnant polarization and the coercive voltage may be maintained low, and accordingly, a low-voltage operation may be effectively implemented, and the reliability of a device according to the repeated programming and erasing may be improved.
Referring to
In the semiconductor device 100 having a metal-ferroelectric-insulator-semiconductor (MFIS) structure according to various example embodiments, by reducing the doping concentration of the channel layer 115 of the substrate 110, the strength of an electric field applied to the ferroelectric layer 140 may be reduced, and accordingly, the remnant polarization and the coercive voltage may be reduced.
In the semiconductor device 100 according to various example embodiments, by making the doping concentration of the channel layer 115 be within a range of 1×1015 cm−3 to 1×1021cm−3, the remnant polarization 2Pr may be about 20 [μC/cm2] or less, and the coercive voltage +Vc may be about 3[V] or less.
As described above, in the semiconductor device 100 according to various example embodiments, by making the doping concentration of the channel layer 115 be relatively lower than that of existing ferroelectric semiconductor device, the remnant polarization and/or the coercive voltage may be maintained low, and accordingly, the low-voltage operation may be more effectively implemented, and/or the reliability of a device according to the repeated programming and erasing may be improved.
The doping concentration of the channel layer 115 may be determined by various methods, such as but not limited to transmission electron microscopy (TEM) and/or secondary ion mass spectrometry (SIMS) such as time-of-flight SIMS (TOF-SIMS); however, example embodiments are not limited thereto.
Referring to
The substrate 210 may include various materials. The channel layer 215 is provided on (e.g. directly on) an upper surface of the substrate 210. The channel layer 215 may be provided as a material layer separate from the substrate 210. The channel layer 215 may include at least one of, for example, an oxide semiconductor, a nitride semiconductor, an oxynitride semiconductor, a 2D material, quantum dots, or an organic semiconductor.
The channel layer 215 may include a dopant of a certain concentration. The dopant may include, for example, a p-type dopant including a group III element such as B, Al, Ga, In, and the like or an n-type dopant including a group V element such as P, As, Sb, and the like. The channel layer 215 may have, for example, a doping concentration of 1×1015 cm−3 to 1×1021 cm−3. As a detailed example, the channel layer 215 may have a doping concentration of 1×1015 cm−3to 1×1021 cm−3.
The source 221 and the drain 222 may be provided at opposite sides of the channel layer 215. The source 221 may be provided to be connected to one side of the channel layer 215, and the drain 222 may be provided to be connected to the other side of the channel layer 215. The source and drain 221 and 222 may include a conductive material and may include the same, or different materials. The paraelectric layer 230, the ferroelectric layer 240, and the gate 250 are sequentially stacked on and above the channel layer 215, which is described above, and thus detailed descriptions thereof are omitted.
In various example embodiments as described above, the semiconductor devices 100 and 200, in which the channel layers 115 and 215 have a sheet or planar channel structure, are described as examples. However, the disclosure is not limited thereto, and a semiconductor device, in detail, a fin-FET, in which the channel layer has a fin channel structure, or a semiconductor device, in detail, a gate-all-around-FET, in which the channel layer has a gate-all-around channel structure, may be provided.
Referring to
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According to another aspect, a semiconductor apparatus including the semiconductor devices 100, 200, 300, and 400 described above may be provided. The semiconductor apparatus may include a plurality of semiconductor devices, and may be in the form in which a field effect transistor and a capacitor are electrically connected to each other. The semiconductor apparatus may have memory properties, for example, a dynamic random access memory (DRAM) device and the like.
Referring to
The capacitor 500 may include first and second electrodes 510 and 520 and a dielectric layer 530 provided between the first and second electrodes 510 and 520. One of the first and second electrodes 510 and 520 of the capacitor 500 may be electrically connected to one of the source and drain 121 and 122 of the field effect transistor or semiconductor device 100 via the contact 62. The contact 62 may include an appropriate conductive material, for example, one or more of tungsten, copper, aluminum, polysilicon, and the like. The capacitor 500 may be a linear capacitor, or may alternatively be a memristor memory element; however, example embodiments are not limited thereto.
The arrangement of the field effect transistor/semiconductor device 100 and the capacitor 500 may be variously changed. For example, the capacitor 500 may be arranged above the substrate 110 or may have a structure that is embedded in the substrate 110.
The semiconductor apparatus D10 described above may be applied to various electronic apparatuses. For example, the semiconductor apparatus D10 described above may be used for one or more of an arithmetic operation, program execution, temporary data retention, and the like in an electronic apparatus such as a mobile device, a computer, a notebook computer, a sensor, a network device, a neuromorphic device, and the like.
Referring to
Each of or at least one of the memory unit 1010, the ALU 1020 and the control unit 1030 may independently include the semiconductor devices described above such as a field effect transistor, a capacitor and/or other passive device such as a memristor, and the like. For example, each of the ALU 1020 and the control unit 1030 may independently include the field effect transistor described above, and the memory unit 1010 may include the capacitor, field effect transistor, or a combination thereof, as described above. The memory unit 1010 may include both a main memory and a cache memory. The electronic device architecture 1000 may be an on-chip memory processing unit.
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The semiconductor device 100 may also include a spacer 160 on a sidewall of each of or at least one of the ferroelectric layer 140, the gate 150, and the paraelectric layer 130. The spacer may be or may include a nitride, such as silicon nitride; however, example embodiments are not limited thereto.
The semiconductor device 100 may further include a first lightly doped drain (LDD) 123 within the substrate 110, under the spacer 160, and between the channel 115 and the source 121. The first LDD 123 may include dopants at an impurity concentration less than that of the source 121. The dopants included in the first LDD 123 may be of the same conductivity type as dopants included in the source 121; however, example embodiments are not limited thereto.
The semiconductor device 100 may further include a second lightly doped drain (LDD) 124 within the substrate 110, under the spacer 160, and between the channel 115 and the drain 122. The second LDD 124 may include dopants at an impurity concentration less than that of the drain 122. The dopants included in the second LDD 124 may be of the same conductivity type as dopants included in the drain 122; however, example embodiments are not limited thereto.
The semiconductor device 100 may further include first and second halo or pocket regions 125 and 126. The first and second halo or pocket regions 125 and 126 may be doped with impurities of the conductivity type opposite to that of the source 121 and the drain 122; however, example embodiments are not limited thereto.
Referring to
The dose of the first dopants may be such that the channel layer 115 is formed within the substrate 110 at a concentration of greater than or equal to 1×1015 cm−3 and less than or equal to 1×1021 cm−3. The implantation may be performed with a beamline implantation tool, and/or a plasma assisted doping tool, and may be performed one time or several times at the same dose or different doses and at the same energy or different energies.
A ferromagnetic layer 140 may be deposited on the channel layer 115 (S162). For example the ferromagnetic layer may be deposited with a chemical vapor deposition (CVD) process; however, example embodiments are not limited thereto.
The source and drain 121 and 122 may be formed (S163). The source and the drain 121 and 122 may be formed after the ferromagnetic layer 140 is formed. For example, the source and the drain 121 and 122 may be formed with an implantation process. Dopants in the implantation process may be of opposite conductivity type to that used in S161; however, example embodiments are not limited thereto.
In the ferroelectric semiconductor device according to the embodiments described above, by making the doping concentration of a channel layer relatively lower than the doping concentration of the existing ferroelectric semiconductor device, the remnant polarization value and the coercive voltage may be maintained low, and accordingly, a low-voltage operation may be more effectively implemented, and/or the reliability of a device according to repeated cycles of programming and erasing may be improved.
Any of the elements and/or functional blocks disclosed above may include or be implemented in processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. The processing circuitry may include electrical components such as at least one of transistors, resistors, capacitors, etc. The processing circuitry may include electrical components such as logic gates including at least one of AND gates, OR gates, NAND gates, NOT gates, etc.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each variously described example embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.
Number | Date | Country | Kind |
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10-2021-0158042 | Nov 2021 | KR | national |