Integrated circuit with metal gate having dielectric portion over isolation area
10756085 ยท 2020-08-25
Assignee
Inventors
Cpc classification
H01L21/823437
ELECTRICITY
H01L27/088
ELECTRICITY
H01L21/823431
ELECTRICITY
H01L21/823878
ELECTRICITY
G06F30/398
PHYSICS
H01L21/823821
ELECTRICITY
H01L21/823481
ELECTRICITY
H01L27/0886
ELECTRICITY
H01L21/823828
ELECTRICITY
H01L27/0924
ELECTRICITY
International classification
H01L27/088
ELECTRICITY
H01L21/768
ELECTRICITY
H01L21/762
ELECTRICITY
G06F30/398
PHYSICS
H01L21/8234
ELECTRICITY
H01L27/06
ELECTRICITY
Abstract
An integrated circuit may include a substrate, a first three-dimensional (3D) transistor formed on a first diffusion region of the substrate, and a second 3D transistor formed on a second diffusion region of the substrate. The first 3D transistor may include a gate that extends from between a source and a drain of the first 3D transistor, across an isolation region of the substrate, to and between a source and a drain of the second 3D transistor. The gate may include a gate metal that has an isolation portion extending over the isolation region of the substrate and a diffusion portion extending over the first and second diffusion regions of the substrate. The isolation portion of the gate metal has a thickness less than a maximum thickness of the diffusion portion of the gate metal.
Claims
1. An integrated circuit, comprising: a substrate; a first three-dimensional (3D) transistor formed on a first diffusion region of the substrate, the first 3D transistor including a first source, a first drain, a plurality of first fins, and a gate, the gate wrapped around the plurality of first fins and extending across the first diffusion region between the first source and the first drain; a second 3D transistor formed on a second diffusion region of the substrate, the second 3D transistor including a second source, a second drain, a plurality of second fins, and the gate wrapped around the plurality of second fins and extending across the second diffusion region between the second source and the second drain; wherein the gate extends from the first 3D transistor across an isolation region of the substrate to the second 3D transistor, the gate including a gate metal, wherein the gate metal has an isolation portion extending over the isolation region of the substrate and a diffusion portion extending over the first diffusion region and the second diffusion region; and a gate dielectric material having a top, a bottom, and sidewalls, the bottom of the gate dielectric material positioned in contact with a top surface of the substrate such that the bottom of the gate dielectric material does not extend into the substrate, the top of the gate dielectric material substantially co-planar with tops of the plurality of first fins and the plurality of second fins, the gate dielectric material positioned between the isolation portion of the gate metal and the substrate, the gate dielectric material positioned such that the isolation portion of the gate metal extends over the top and the sidewalls of the gate dielectric material, the isolation portion of the gate metal having a thickness less than a maximum thickness of the diffusion portion of the gate metal.
2. The integrated circuit of claim 1, wherein the gate dielectric material having a thickness in the range of 40 nm to 60 nm.
3. The integrated circuit of claim 1, wherein the thickness of the isolation portion of the gate metal is in the range of 10 nm to 35 nm.
4. The integrated circuit of claim 1, wherein the gate metal is composed of a material selected from the group consisting of cobalt and tungsten.
5. The integrated circuit of claim 1, wherein the gate further includes a conducting layer disposed on the gate metal.
6. The integrated circuit of claim 5, wherein the conducting layer has a thickness in the range of 10 nm to 30 nm.
7. The integrated circuit of claim 5, wherein the conducting layer is composed of a material selected from the group consisting of graphene, copper, aluminum, and gold.
8. The integrated circuit of claim 1, integrated into a mobile phone, a set top box, a music player, a video player, an entertainment unit, a navigation device, a computer, a hand-held personal communication systems (PCS) unit, a portable data unit, and/or a fixed location data unit.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) For a more complete understanding of the present disclosure, reference is now made to the following description taken in conjunction with the accompanying drawings.
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DETAILED DESCRIPTION
(15) The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. It will be apparent to those skilled in the art, however, that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.
(16) As described herein, the use of the term and/or is intended to represent an inclusive OR, and the use of the term or is intended to represent an exclusive OR. As described herein, the term exemplary used throughout this description means serving as an example, instance, or illustration, and should not necessarily be construed as preferred or advantageous over other exemplary configurations. As described herein, the term coupled used throughout this description means connected, whether directly or indirectly through intervening connections (e.g., a switch), electrical, mechanical, or otherwise, and is not necessarily limited to physical connections. Additionally, the connections can be such that the objects are permanently connected or releasably connected. The connections can be through switches. As described herein, the term proximate used throughout this description means adjacent, very near, next to, or close to. As described herein, the term on used throughout this description means directly on in some configurations, and indirectly on in other configurations.
(17) According to aspects of the present disclosure, a dielectric material may be provided to at least partially replace a gate metal over an isolation region of a substrate. The advantages of replacing a portion of the gate metal over the isolation region with a dielectric material include reducing gate to contact parasitic capacitance by approximately 70% and improving chip performance by as much as 5-10%.
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(19) To reduce 3D parasitic capacitances, according to aspects of the present disclosure, an IC may be provided, in which a portion of a gate that extends over an isolation region of a substrate is replaced with a dielectric material, thereby reducing coupling between the gate and any source and/or drain contacts of proximate FinFETs.
(20) The IC 400 is similar to the IC 300 shown in
(21) The gate dielectric material 418 may be a silicon nitride or any other suitable dielectric material, including a combination of dielectric materials. The gate dielectric material 418, which is disposed between the isolation region 408 of the substrate and the gate metal 416, may have a thickness in the range of 40 nm to 60 nm. As mentioned above, the gate dielectric material 418 replaces a portion of the gate metal 416 over the isolation region 408 of the substrate, thereby reducing the 3D parasitic coupling capacitance of the gate metal 416 over the isolation region 408 to the contacts of the source 410 and the drain 412 of neighboring FinFETs, such as FinFET 402. This reduction in 3D parasitic capacitance will improve the performance of advanced CMOS devices.
(22) According to aspects of the present disclosure, an optional conducting layer may further be provided on the gate metal 416.
(23) The conducting layer 420 may be composed of a material having a higher conductivity than the gate metal 416 to improve gate conductance. For example, if the gate metal 416 is made of tungsten or cobalt, the conducting layer may be composed a carbon material, such as graphene. Other suitable materials for the conducting layer 420 that have a higher conductivity than tungsten or cobalt include silver, copper, gold, aluminum and calcium. The conducting layer 420 may have a thickness T.sub.C in the range of 10 nm to 30 nm.
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(28) The thickness of the additional layer 626 of gate metal may vary, depending on whether the gate will include an optional conducting layer on top of the gate metal. If no conducting layer will be added to the gate, the additional layer 626 of gate metal may, for example, have a thickness in the range of 10 nm to 35 nm. If a conducting layer will be added to the gate, then the additional layer 626 of gate material may, for example, be a thin layer having a thickness in the range of 1 nm to 5 nm.
(29) At block 512 of
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(38) Data recorded on the storage medium 1004 may specify logic circuit configurations, pattern data for photolithography masks, or mask pattern data for serial write tools such as electron beam lithography. The data may further include logic verification data such as timing diagrams or net circuits associated with logic simulations. Providing data on the storage medium 1004 facilitates the design of the circuit 1010 or the IC device 1012 by decreasing the number of processes for designing semiconductor wafers.
(39) For a firmware and/or software implementation, the methodologies may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. A machine-readable medium tangibly embodying instructions may be used in implementing the methodologies described herein. For example, software codes may be stored in a memory and executed by a processor unit. Memory may be implemented within the processor unit or external to the processor unit. As used herein, the term memory refers to types of long term, short term, volatile, nonvolatile, or other memory and is not to be limited to a particular type of memory or number of memories, or type of media upon which memory is stored.
(40) If implemented in firmware and/or software, the functions may be stored as one or more instructions or code on a computer-readable medium. Examples include computer-readable media encoded with a data structure and computer-readable media encoded with a computer program. Computer-readable media includes physical computer storage media. A storage medium may be an available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer; disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
(41) In addition to storage on computer readable medium, instructions and/or data may be provided as signals on transmission media included in a communication apparatus. For example, a communication apparatus may include a transceiver having signals indicative of instructions and data. The instructions and data are configured to cause one or more processors to implement the functions outlined in the claims.
(42) Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the technology of the disclosure as defined by the appended claims. For example, relational terms, such as above and below are used with respect to a substrate or electronic device. Of course, if the substrate or electronic device is inverted, above becomes below, and vice versa. Additionally, if oriented sideways, above and below may refer to sides of a substrate or electronic device. Moreover, the scope of the present application is not intended to be limited to the particular configurations of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding configurations described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
(43) Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
(44) The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).
(45) The steps of a method or algorithm described in connection with the disclosure may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
(46) In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store specified program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
(47) The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.