Carbon-based standard cell circuits and integrated circuits

Abstract

A carbon-based standard unit circuit and integrated circuit includes at least one carbon nanotube transistor unit. The carbon nanotube transistor unit comprises two or more carbon nanotube transistors connected in series. Each carbon nanotube in the unit contains different carbon nanotubes, and all carbon nanotubes in the unit have the same carrier conductivity type. The gates of all carbon nanotube transistors are connected. By setting two or more carbon nanotube transistors connected in series within the same unit, the number of carbon nanotubes within the unit is increased. Since each carbon nanotube contains different carbon nanotubes but has the same carrier conductivity type, the carbon nanotubes in each unit exhibit different intrinsic material properties. This reduces the probability that all carbon nanotubes in the unit contain metallic carbon nanotubes, thereby reducing the probability of the carbon nanotube transistor unit malfunctioning.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and more particularly to a carbon-based standard cell circuit and integrated circuit. Background Technology

[0002] Carbon-based standard cell circuits refer to reusable basic digital circuit units designed according to CMOS complementary logic, with carbon nanotube transistors (CNFETs) as the core device.

[0003] Carbon nanotubes (CNTs) are the core channel material in carbon nanotube field-effect transistors (CNTFETs). The large-scale integration of CNTFETs has been limited by the inherent defects of carbon nanotubes. Depending on their chirality, carbon nanotubes can exhibit either metallic or semiconducting intrinsic material properties. Metallic carbon nanotubes, with a band gap of zero or near zero, cannot have their conduction controlled by the gate. Their presence inside a carbon nanotube transistor can cause a significant decrease in the switching current ratio or even a source-drain short circuit, affecting circuit performance. Semiconducting carbon nanotubes, on the other hand, have a band gap. When a gate voltage is applied, a large number of charge carriers conduct (on state), and when no gate voltage is applied, they do not conduct (off state), thus enabling switching functionality. Therefore, carbon nanotube transistors using semiconducting carbon nanotubes as the conductive channel can achieve switching functionality by controlling the channel conduction through the gate voltage.

[0004] Currently, before applying voltage to a carbon nanotube transistor to make it conduct, it is necessary to detect the intrinsic material properties of the carbon nanotubes in the carbon nanotube transistor to remove the metallic carbon nanotubes inside the carbon nanotube transistor. However, this approach cannot completely remove the metallic carbon nanotubes, leaving residues of metallic carbon nanotubes inside the carbon nanotube transistor. Furthermore, it can damage the semiconductor carbon nanotubes, affecting the working performance of the carbon nanotube transistor and the carbon-based standard cell circuit. Summary of the Invention

[0005] The technical problem solved by this invention is how to improve the working performance of carbon nanotube transistors and carbon-based standard unit circuits.

[0006] To address the aforementioned technical problems, this invention provides a carbon-based standard unit circuit, comprising at least one carbon nanotube transistor unit; the carbon nanotube transistor unit comprises two or more carbon nanotube transistors connected in series; each carbon nanotube in the carbon nanotube transistor unit contains different carbon nanotubes, each carbon nanotube in the carbon nanotube transistor unit has the same carrier conductivity type, and the gates of each carbon nanotube transistor are connected.

[0007] Optionally, at least one carbon nanotube in the carbon nanotube transistor unit is a semiconducting carbon nanotube.

[0008] Optionally, the carbon nanotube transistor unit includes a first carbon nanotube transistor and a second carbon nanotube transistor connected in series.

[0009] Optionally, the carbon nanotubes in the same carbon nanotube transistor unit are arranged along a first direction, which is perpendicular to the extension direction of the carbon nanotubes in the carbon nanotube transistor.

[0010] Optionally, the carbon-based standard unit circuit includes: two or more carbon nanotube transistor units; the carbon nanotube transistors in the two or more carbon nanotube transistor units are arranged along a first direction.

[0011] Optionally, the carbon-based standard unit circuit includes: a first carbon nanotube transistor unit and a second carbon nanotube transistor unit, wherein the carbon nanotube transistors in the first carbon nanotube transistor unit and the second carbon nanotube transistor unit are arranged along a first direction.

[0012] Optionally, the control terminal of the first carbon nanotube transistor unit is connected to the control terminal of the second carbon nanotube transistor unit to form a first inverter circuit.

[0013] Optionally, the carbon-based standard unit circuit further includes: a third carbon nanotube transistor unit and a fourth carbon nanotube transistor unit, wherein the control terminal of the third carbon nanotube transistor unit is connected to the control terminal of the fourth carbon nanotube transistor unit to form a second inverter circuit; the control terminal of the second inverter circuit is connected to the output terminal of the first inverter circuit.

[0014] Optionally, the two or more carbon nanotube transistor units are connected to form a NAND gate circuit.

[0015] Optionally, the number of carbon nanotube transistors in each of the carbon nanotube transistor units is the same.

[0016] Optionally, the charge carrier conductivity type of each carbon nanotube in the carbon nanotube transistor unit is either P-type or N-type.

[0017] Accordingly, the present invention also provides an integrated circuit comprising the carbon-based standard cell circuit described above.

[0018] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects: In this invention, by setting two or more carbon nanotubes connected in series within a carbon nanotube transistor unit, since the carbon nanotubes contained in each carbon nanotube in the same unit are different but have the same charge carrier conductivity type, the carbon nanotubes in each carbon nanotube can have different intrinsic material properties. Thus, by increasing the number of carbon nanotubes with the same charge carrier conductivity type within the same unit, the probability that all carbon nanotubes in the unit contain metallic carbon nanotubes can be reduced, and the number of carbon nanotubes containing semiconducting carbon nanotubes can be increased. This reduces the probability of carbon nanotube unit failure. In this case, as long as one carbon nanotube in the unit contains a semiconducting carbon nanotube, the unit can operate normally without the need to remove metallic carbon nanotubes in advance or use additional chemical solvents to remove them. This avoids damage to the carbon nanotubes caused by removing metallic carbon nanotubes, reduces process costs, and improves the performance of carbon-based standard unit circuits.

[0019] Furthermore, in the circuit layout, by arranging the carbon nanotubes in the same carbon nanotube transistor unit along a first direction, which is perpendicular to the extension direction of the carbon nanotubes in the carbon nanotube transistor, the asymmetry of the carbon nanotubes in the carbon nanotube transistor in the first direction is utilized. That is, the intrinsic material properties of the carbon nanotubes of different carbon nanotube transistors in the first direction are not related. This ensures that when any carbon nanotube in the first direction fails due to the presence of metallic carbon nanotubes, the remaining carbon nanotubes in the first direction are not affected by the failed carbon nanotube and can still realize the circuit function of the corresponding carbon nanotube transistor unit, thereby further improving the performance of the carbon-based standard unit circuit. Attached Figure Description

[0020] Figures 1 to 2 This is a schematic diagram of the structure of carbon nanotubes in a carbon nanotube transistor. Figure 3 This is a schematic diagram of the structure of a carbon-based standard unit circuit in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a P-type carbon nanotube transistor in a carbon-based standard unit circuit according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of an N-type carbon nanotube transistor in a carbon-based standard unit circuit according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a carbon nanotube transistor in one embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention; Figure 8This is a schematic diagram of the carbon-based standard cell circuit layout in another embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention; Figure 12 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention. Detailed Implementation

[0021] It should be noted that the terms "surface" and "on" in this specification are used to describe the relative spatial position and are not limited to whether there is direct contact.

[0022] Currently, methods such as electrical breakdown of all carbon nanotubes to break down metallic carbon nanotubes and remove them, or chemical solvent removal, are used. However, neither of these methods can completely remove metallic carbon nanotubes; metallic carbon nanotubes remain inside carbon nanotube field-effect transistors (FETs). Furthermore, these methods can damage semiconducting carbon nanotubes, affecting the performance of FETs and carbon-based standard cell circuits. The reasons for these shortcomings are analyzed below: Figure 1 This is a schematic diagram of the carbon nanotube structure within a carbon nanotube transistor. (Refer to...) Figure 1 The carbon nanotube transistor has a plurality of carbon nanotubes 100, and the carbon nanotubes have interdigitated electrodes 101.

[0023] The carbon nanotubes and the interdigitated electrodes located on the carbon nanotubes constitute a VMR (VLSI-Compatible Metallic-CNT Removal) structure.

[0024] It should be noted that, Figure 1 The carbon nanotubes 100 mentioned herein may include metallic carbon nanotubes and semiconductor carbon nanotubes, and the type of carbon nanotubes 100 needs to be determined after testing.

[0025] refer to Figure 2 By applying a high voltage to all carbon nanotubes 100 at once using a VMR structure, metallic carbon nanotubes 1002 are broken down during the process. It can be determined that the broken down carbon nanotubes 100 are metallic carbon nanotubes 1002, and the unbroken carbon nanotubes 100 are semiconductor carbon nanotubes 1001.

[0026] In practical applications, when high voltage is applied to all carbon nanotubes, not all metallic carbon nanotubes are broken down, leaving residual metallic carbon nanotubes within the carbon nanotubes, which affects the operating performance of the carbon nanotube field-effect transistor. Furthermore, applying high voltage to all carbon nanotubes may also cause semiconducting carbon nanotubes to break down, further impacting the operating performance of the carbon nanotube field-effect transistor.

[0027] In addition, there are also methods that use chemical solvents to remove metallic carbon nanotubes, with the specific steps as follows: The first step involved adding 500 mg of carbon nanotube raw material and 500 mg of di-tert-butylcarbazole (DBPCz) to 500 ml of toluene solvent. The mixture was then ultrasonically dispersed at 500 W for 20 minutes using a probe-type ultrasonic disperser, followed by centrifugation at 50,000 g for 3 hours, and 90% of the supernatant was collected.

[0028] The second step is to centrifuge the supernatant again for 30 minutes and collect 90% of the supernatant again. This will give you a carbon nanotube dispersion with a semiconductor purity greater than 99.9%.

[0029] The third step involves filtering the carbon nanotube dispersion in the toluene system obtained in the second step. A polytetrafluoroethylene (PTFE) filter membrane with a pore size of 0.1 micrometers is selected as the filter membrane. This causes the semiconducting carbon nanotubes to change from a dispersed state in toluene to a solid state.

[0030] Fourth step: Take 200ml of tetrahydrofuran and disperse it by ultrasonication, so that it changes from solid to suspension in solution again. Centrifuge at 20000g for 30 minutes to remove carbon nanotubes that have not been monodispersed. Collect the supernatant and filter it again using a PTFE filter membrane with a pore size of 0.1 micrometers to obtain a filter membrane containing carbon nanotubes and polymer. Repeat twice. The fifth step involves using 200 ml of trichloroethane for final dispersion, which yields a carbon nanotube dispersion with a semiconductor purity greater than 99.9999% in the trichloroethane system.

[0031] The above-mentioned methods for removing metallic carbon nanotubes using chemical solvents require specific chemical solvents, increasing production costs. Furthermore, these methods are highly dependent on specific process equipment and operator experience, resulting in poor portability and making them difficult to widely reuse in other manufacturers. Additionally, the removal of metallic carbon nanotubes using these methods can easily damage carbon nanotube transistors, affecting their reliability.

[0032] To address the aforementioned technical problems, this invention provides a carbon-based standard unit circuit and integrated circuit. By setting two or more carbon nanotubes connected in series within the same carbon nanotube transistor unit, the number of carbon nanotubes within the unit is increased. Furthermore, while each carbon nanotube contains different types of carbon nanotubes, they exhibit the same carrier conductivity. This results in different intrinsic material properties of the carbon nanotubes in each unit, reducing the probability that all carbon nanotubes in the unit contain metallic carbon nanotubes and increasing the number of carbon nanotubes containing semiconducting carbon nanotubes. Consequently, the probability of failure in the carbon nanotube transistor unit can be reduced.

[0033] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] refer to Figure 3 The carbon-based standard unit circuit includes at least one carbon nanotube transistor unit 200; the carbon nanotube transistor unit 200 includes two or more carbon nanotube transistors connected in series; the carbon nanotubes contained in each carbon nanotube transistor in the carbon nanotube transistor unit 200 are different, the carrier conductivity type of each carbon nanotube transistor in the carbon nanotube transistor unit 200 is the same, and the gates of each carbon nanotube transistor are connected.

[0035] In specific implementation, the carbon nanotubes contained in each carbon nanotube transistor are different, which means that the carbon nanotubes contained in any two carbon nanotube transistors in the carbon nanotube transistor unit 200 are completely different, that is, the carbon nanotubes contained in any two carbon nanotube transistors do not overlap.

[0036] Because the carbon nanotubes in each carbon nanotube of the carbon nanotube transistor unit 200 are different, the probability that the carbon nanotubes in the carbon nanotube transistors of the carbon nanotube transistor unit 200 are semiconducting carbon nanotubes can be increased, thereby reducing the probability of failure of the carbon nanotube transistor unit 200. At this time, when at least one carbon nanotube in the carbon nanotube transistor contains a semiconducting carbon nanotube, the carbon nanotube transistor unit 200 can work normally.

[0037] In a specific implementation, if a carbon nanotube is included in the carbon nanotube transistor unit, assuming that the probability that a single carbon nanotube of the carbon nanotube transistor possesses semiconductor properties is P... semi Furthermore, the channel region of a carbon nanotube transistor contains N cnt Carbon nanotubes. Under these conditions, the probability that the carbon nanotubes in a carbon nanotube transistor exhibit semiconductor properties can be expressed as: (1) When a carbon nanotube transistor unit includes two or more carbon nanotube transistors connected in series, the probability that the carbon nanotubes within the two or more series-connected carbon nanotube transistors exhibit semiconductor properties can be expressed as: (2) Semiconducting carbon nanotubes can achieve a purity of 99.9999375%, i.e., P semi =0.999999375; the channel region of a carbon nanotube transistor contains an average of 180 carbon nanotubes, i.e., N cnt =180. According to formula (1) and calculation, the probability that the carbon nanotube in a carbon nanotube transistor exhibits semiconductor properties is 99.98875%; according to formula (2) and calculation, the probability that the carbon nanotube in two or more carbon nanotube transistors connected in series exhibits semiconductor properties is 99.9999987%.

[0038] Therefore, it can be seen that using a carbon nanotube transistor unit that includes two or more carbon nanotube transistors connected in series can increase the probability that the carbon nanotubes in the carbon nanotube transistors in the carbon nanotube transistor unit 200 are semiconducting carbon nanotubes.

[0039] In practical implementation, based on the carrier conductivity type, carbon nanotube transistors can be divided into P-type transistors and N-type transistors. In the embodiments of this invention, within the same carbon nanotube transistor unit 200, the carrier conductivity type of the carbon nanotube transistor, for example, refers to... Figure 3 The charge carrier conductivity type of each carbon nanotube transistor in the carbon nanotube transistor unit 200 is N-type.

[0040] In a specific implementation, within the same carbon nanotube transistor unit 200, each carbon nanotube transistor is connected in series, and the gates of each carbon nanotube transistor are connected to each other. This can effectively replace the carbon nanotube transistor unit originally implemented by a single carbon nanotube transistor with multiple carbon nanotube transistors that are connected in series with the same carrier conductivity type, thereby reducing the probability of failure of the carbon nanotube transistor unit 200.

[0041] Specifically, refer to Figure 3Taking the example that the carrier conductivity type of each carbon nanotube in the carbon nanotube transistor unit 200 is N-type, the carbon nanotube transistor unit 200 includes: a first carbon nanotube transistor 2011, a second carbon nanotube transistor 2012, ..., an Nth carbon nanotube transistor 201N. The gate of the first carbon nanotube transistor 2011 is connected to the gate of the Nth carbon nanotube transistor 201N as the input terminal of the carbon nanotube transistor unit 200. The drain of the first carbon nanotube transistor 2011 is connected to the power supply voltage terminal VDD. The source of the first carbon nanotube transistor 2011 is connected to the drain of the second carbon nanotube transistor 2012, ..., the source of the (N-1)th carbon nanotube transistor 201(N-1) is connected to the drain of the Nth carbon nanotube transistor 201N. The source of the Nth carbon nanotube transistor 201N is grounded to GND.

[0042] In practical implementation, the number of carbon nanotube transistors within the same carbon nanotube transistor unit 200 is at least two. For example, refer to... Figure 4 The same carbon nanotube transistor unit 200 can be composed of two P-type carbon nanotube transistors, or refer to Figure 5 It consists of two N-type carbon nanotube transistors.

[0043] In other embodiments, the value of N can also be 3, 5, 7, etc.

[0044] The carbon nanotube transistors in the carbon nanotube transistor unit have the same conduction type, which enables the carbon nanotube transistors in the same carbon nanotube transistor unit to achieve the same circuit function. In this way, the circuit function of multiple carbon nanotube transistors is equivalent to the circuit function of one carbon nanotube transistor, ensuring the normal circuit function of the carbon nanotube transistor unit.

[0045] In some implementations, at least one carbon nanotube in the carbon nanotube transistor unit is entirely composed of semiconducting carbon nanotubes. Specifically, the carbon nanotube transistor unit includes a first carbon nanotube transistor and a second carbon nanotube transistor connected in series, wherein all carbon nanotubes in the first carbon nanotube transistor are semiconducting carbon nanotubes, and at least one metallic carbon nanotube is present in the carbon nanotubes in the second carbon nanotube transistor.

[0046] In some implementations, each carbon nanotube in the same carbon nanotube transistor unit 200 is arranged along a first direction Y, which is perpendicular to the extension direction of the carbon nanotubes in the carbon nanotube transistor.

[0047] This invention utilizes the asymmetry of the intrinsic material properties of different carbon nanotube transistors in the first direction Y, that is, the intrinsic material properties of different carbon nanotube transistors in the first direction Y are not correlated. This allows the remaining carbon nanotube transistors in the first direction Y to remain unaffected by the faulty carbon nanotube transistor and still perform the circuit function of the corresponding carbon nanotube transistor unit, thereby improving the performance of carbon-based standard unit circuits.

[0048] The following is combined with Figure 6 The intrinsic material properties of carbon nanotube transistors are explained, including the asymmetry in the first direction Y and the symmetry in the second direction X.

[0049] refer to Figure 6 A number of carbon nanotubes are formed on the substrate along the first direction Y, and each carbon nanotube extends along the second direction X, where the second direction X is the extension direction of the carbon nanotube.

[0050] Along the first direction Y, the carbon nanotubes can be divided into a first group of carbon nanotubes 202 and a second group of carbon nanotubes 203. The first group of carbon nanotubes 202 is used to form a first carbon nanotube transistor M1 and a second carbon nanotube transistor M2, and the second group of carbon nanotubes 203 is used to form a third carbon nanotube transistor M3 and a fourth carbon nanotube transistor M4.

[0051] In this diagram, the carbon nanotubes shown by the black solid line represent semiconducting carbon nanotubes, while those shown by the red solid line represent metallic carbon nanotubes. Semiconducting carbon nanotubes have a band gap, allowing them to conduct with a large number of charge carriers when a gate voltage is applied (on state) and to remain nonconducting when no gate voltage is applied (off state), thus enabling them to function as switching devices, i.e., carbon nanotube transistors. Metallic carbon nanotubes, on the other hand, have no band gap, meaning they remain always on regardless of the applied voltage or the gate voltage, and therefore cannot be used as logic gates.

[0052] Since the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 have the same carbon nanotubes, they are carbon nanotube transistors with the same carbon nanotubes. Similarly, the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 are carbon nanotube transistors with the same carbon nanotubes.

[0053] Since the first carbon nanotube transistor M1 and the third carbon nanotube transistor M3 have different carbon nanotubes, they are carbon nanotube transistors with different carbon nanotubes. Similarly, the first carbon nanotube transistor M1 and the fourth carbon nanotube transistor M4, the second carbon nanotube transistor M2 and the third carbon nanotube transistor M3, and the second carbon nanotube transistor M2 and the fourth carbon nanotube transistor M4 are also carbon nanotube transistors with different carbon nanotubes.

[0054] By using carbon nanotubes to form carbon nanotube transistors, standard carbon nanotube transistor units can be formed. For example, a standard carbon nanotube transistor unit can be formed by using a first carbon nanotube transistor M1 and a fourth carbon nanotube transistor M4, or by using a second carbon nanotube transistor M2 and a fourth carbon nanotube transistor M4. This can avoid the probability that all carbon nanotube transistors contain the metallic nanotube, thereby increasing the probability that a carbon nanotube transistor containing a semiconductor nanotube appears in the standard carbon nanotube transistor unit.

[0055] Regarding the symmetry of the intrinsic material properties of carbon nanotube transistors in the second direction X, the carbon nanotubes in the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 are both carbon nanotubes from the first group of carbon nanotubes 202. Therefore, the intrinsic material properties of the carbon nanotubes in the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 are the same. For example, both the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 include four semiconducting carbon nanotubes and one metallic carbon nanotube, meaning that both the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 will be short-circuited after a voltage is subsequently applied.

[0056] The carbon nanotubes in both the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 are carbon nanotubes of the second group of carbon nanotubes 203. Therefore, the intrinsic material properties of the carbon nanotubes in the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 are the same. For example, the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 are all semiconducting carbon nanotubes, meaning that the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 can function as normal switches after a voltage is subsequently applied.

[0057] Therefore, the identical intrinsic material properties of carbon nanotubes in the first carbon nanotube transistor M1 and the second carbon nanotube transistor M2 in the second direction X, as well as the identical intrinsic material properties of carbon nanotubes in the third carbon nanotube transistor M3 and the fourth carbon nanotube transistor M4 in the second direction X, are referred to as symmetry.

[0058] Regarding the asymmetry of the intrinsic material properties of carbon nanotube transistors in the first direction Y, the carbon nanotubes in the first carbon nanotube transistor M1 are those in the first group of carbon nanotubes 202, and the carbon nanotubes in the third carbon nanotube transistor M3 are those in the second group of carbon nanotubes 203. Therefore, the intrinsic material properties of the carbon nanotubes in the first carbon nanotube transistor M1 and the third carbon nanotube transistor M3 are different. For example, the first carbon nanotube transistor M1 includes four semiconducting carbon nanotubes and one metallic carbon nanotube, while the third carbon nanotube transistor M3 consists entirely of semiconducting carbon nanotubes. The first carbon nanotube transistor M1 will be short-circuited after a voltage is subsequently applied, while the third carbon nanotube transistor M3 can function as a normal switching carbon nanotube transistor after a voltage is subsequently applied.

[0059] The carbon nanotubes in the second carbon nanotube transistor M2 are the same as those in the first group of carbon nanotubes 202, and the carbon nanotubes in the fourth carbon nanotube transistor M4 are the same as those in the second group of carbon nanotubes 203. Therefore, the intrinsic material properties of the carbon nanotubes in the second carbon nanotube transistor M2 and the fourth carbon nanotube transistor M4 are different. For example, the second carbon nanotube transistor M2 includes four semiconducting carbon nanotubes and one metallic carbon nanotube, while the fourth carbon nanotube transistor M4 consists entirely of semiconducting carbon nanotubes. The second carbon nanotube transistor M2 will be short-circuited after a voltage is subsequently applied, while the fourth carbon nanotube transistor M4 can function as a normal switching carbon nanotube transistor after a voltage is subsequently applied.

[0060] Therefore, the different intrinsic material properties of carbon nanotubes in the first carbon nanotube transistor M1 and the third carbon nanotube transistor M3 in the first direction Y, and the different intrinsic material properties of carbon nanotubes in the second carbon nanotube transistor M2 and the fourth carbon nanotube transistor M4 in the first direction Y, are called asymmetry.

[0061] In practical implementation, the carbon-based standard unit circuit can be used to achieve various circuit functions. The following is a detailed explanation in conjunction with the appendix. Figures 7 to 11 Provide a detailed description.

[0062] refer to Figure 7 The carbon-based standard unit circuit includes: a first carbon nanotube transistor unit 301 and a second carbon nanotube transistor unit 302, wherein the carbon nanotube transistors in the first carbon nanotube transistor unit 301 and the second carbon nanotube transistor unit 302 are arranged along the first direction Y.

[0063] In a specific implementation, the control terminal of the first carbon nanotube transistor unit 301 is connected to the control terminal of the second carbon nanotube transistor unit 302 to form a first inverter circuit.

[0064] In some implementations, the first carbon nanotube transistor unit 301 includes two first P-type carbon nanotube transistors 3011 and 3012 connected in series, and the second carbon nanotube transistor unit 302 includes two first N-type carbon nanotube transistors 3021 and 3022 connected in series. The control terminals of the first P-type carbon nanotube transistors 3011, 3012, 3021, and 3022 are connected to form a first inverter circuit. The input terminal IN; the source of the first P-type carbon nanotube transistor 3011 is connected to the power supply voltage terminal VDD, the drain of the first P-type carbon nanotube transistor 3011 is connected to the source of the second P-type carbon nanotube transistor 3012, the drain of the second P-type carbon nanotube transistor 3012 is connected to the drain of the first N-type carbon nanotube transistor 3021, and serves as the output terminal OUT of the first inverter circuit, the source of the first N-type carbon nanotube transistor 3021 is connected to the drain of the second N-type carbon nanotube transistor 3022, and the source of the second N-type carbon nanotube transistor 3022 is grounded.

[0065] The following is combined with Figure 8 right Figure 7 The circuit layout of the first inverter in the circuit is explained.

[0066] exist Figure 7 Based on reference Figure 8 The carbon nanotube transistors in the first carbon nanotube transistor unit 301 and the second carbon nanotube transistor unit 302 are arranged along the first direction Y, which is perpendicular to the second direction X.

[0067] The first carbon nanotube transistor unit 301 contains a P-type carbon nanotube transistor with a gate Mpoly, a PMOS source / drain doped region, and an active region AA. The second carbon nanotube transistor unit 302 contains an N-type carbon nanotube transistor with a gate Mpoly, an NMOS source / drain doped region, and an active region AA. The PMOS source / drain doped region and gate Mpoly of the first P-type carbon nanotube transistor 3011 and the PMOS source / drain doped region and gate Mpoly of the second P-type carbon nanotube transistor 3012 are connected by a first metal layer and a contact hole CT. The NMOS source / drain doped region and gate Mpoly of the first N-type carbon nanotube transistor and the NMOS source / drain doped region and gate Mpoly of the second N-type carbon nanotube transistor are connected by a first metal layer M1 and a contact hole CT. The PMOS source / drain doped region of the second P-type carbon nanotube transistor and the NMOS source / drain doped region of the first N-type carbon nanotube transistor are connected by a second metal layer M2 and a contact hole CT.

[0068] In some embodiments, the vertical arrangement of the metal layers from top to bottom is as follows: second metal layer M2, first metal layer M1, PMOS source / drain doped region or NMOS source / drain doped region, gate Mpoly, and active region AA.

[0069] In other embodiments, the metal layer also includes a cutting metal layer Mcut, which is used to cut the carbon nanotubes between the first P-type carbon nanotube transistor and the first N-type carbon nanotube transistor, as well as between the second P-type carbon nanotube transistor and the second N-type carbon nanotube transistor, to form two independent carbon nanotube transistors.

[0070] In some implementations, the number of carbon nanotubes in each of the carbon nanotube transistor units is the same, such that each P-type carbon nanotube in the carbon nanotube transistor unit corresponds to an N-type carbon nanotube transistor in the second direction X, so that several inverter pairs are formed in the carbon nanotube extension direction X.

[0071] Based on the symmetry of carbon nanotube transistors along the extension direction X, when either the P-type or N-type carbon nanotube transistor is metallic along the second direction X, both the P-type and N-type carbon nanotube transistors are short-circuited.

[0072] In the above scheme, the carbon nanotubes in the same carbon nanotube transistor unit are arranged along a first direction, which is perpendicular to the extension direction of the carbon nanotubes in the carbon nanotube transistor. By utilizing the asymmetry of the carbon nanotubes in the carbon nanotube transistor in the first direction, that is, the intrinsic material properties of the carbon nanotubes of different carbon nanotube transistors in the first direction are not related, when any carbon nanotube in the first direction fails due to the presence of metallic carbon nanotubes, the remaining carbon nanotubes in the first direction are not affected by the failed carbon nanotube and can still realize the circuit function of the corresponding carbon nanotube transistor unit, thereby further improving the performance of the carbon-based standard unit circuit.

[0073] Figure 9 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention.

[0074] exist Figure 7 Based on reference Figure 9 The carbon-based standard unit circuit further includes: a third carbon nanotube transistor unit 303 and a fourth carbon nanotube transistor unit 304. The control terminal of the third carbon nanotube transistor unit 303 is connected to the control terminal of the fourth carbon nanotube transistor unit 304 to form a second inverter circuit. The control terminal of the second inverter circuit is connected to the output terminal of the first inverter circuit.

[0075] In some implementations, the third carbon nanotube transistor unit 303 includes two first P-type carbon nanotube transistors 3031 and second P-type carbon nanotube transistors 3032 connected in series, and the fourth carbon nanotube transistor unit 304 includes two first N-type carbon nanotube transistors 3041 and second N-type carbon nanotube transistors 3042 connected in series. The control terminals of the first P-type carbon nanotube transistor 3031, the second P-type carbon nanotube transistor 3032, and the first N-type carbon nanotube transistor 3041 and second N-type carbon nanotube transistor 3042 are connected, and serve as the first... The input terminal IN of the dual inverter circuit is connected to the power supply voltage terminal VDD. The drain of the first P-type carbon nanotube transistor 3031 is connected to the source of the second P-type carbon nanotube transistor 3032. The drain of the second P-type carbon nanotube transistor 3032 is connected to the drain of the first N-type carbon nanotube transistor 3041 and serves as the output terminal OUT of the second inverter circuit. The source of the first N-type carbon nanotube transistor 3041 is connected to the drain of the second N-type carbon nanotube transistor 3042, and the source of the second N-type carbon nanotube transistor 3042 is grounded.

[0076] In practice, the first inverter circuit and the second inverter circuit constitute a buffer.

[0077] Figure 10 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention.

[0078] refer to Figure 10 The two or more carbon nanotube transistor units are connected to form a 2-input NAND gate circuit.

[0079] In a specific implementation, the two or more carbon nanotube transistor units include: a first carbon nanotube transistor unit 401, a second carbon nanotube transistor unit 402, a third carbon nanotube transistor unit 403, a fourth carbon nanotube transistor unit 404, a fifth carbon nanotube transistor unit 405, and a sixth carbon nanotube transistor unit 406.

[0080] The first carbon nanotube transistor unit 401 to the third carbon nanotube transistor unit 403 are all P-type carbon nanotube transistors, and the fourth carbon nanotube transistor unit 404 to the sixth carbon nanotube transistor unit 406 are all N-type carbon nanotube transistors.

[0081] The control terminals of the first carbon nanotube transistor unit 401 and the fourth carbon nanotube transistor unit 404 are connected to form the first input terminal IN1 of the 2-input NAND gate circuit. The control terminals of the second carbon nanotube transistor unit 402 and the fifth carbon nanotube transistor unit 405 are connected to form the second input terminal IN2 of the 2-input NAND gate circuit. The drain of the third carbon nanotube transistor unit 403 and the drain of the sixth carbon nanotube transistor unit 406 are connected to form the output terminal of the 2-input NAND gate circuit.

[0082] Figure 11 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention.

[0083] refer to Figure 11 The two or more carbon nanotube transistor units are connected to form a three-state gate circuit.

[0084] In a specific implementation, the two or more carbon nanotube transistor units include: a first carbon nanotube transistor unit 501, a second carbon nanotube transistor unit 502, a third carbon nanotube transistor unit 503, a fourth carbon nanotube transistor unit 504, a fifth carbon nanotube transistor unit 505, a sixth carbon nanotube transistor unit 506, a seventh carbon nanotube transistor unit 507, and an eighth carbon nanotube transistor unit 508.

[0085] The first carbon nanotube transistor unit 501, the second carbon nanotube transistor unit 502, the third carbon nanotube transistor unit 503 and the fifth carbon nanotube transistor unit 505 are P-type carbon nanotube transistors, while the fourth carbon nanotube transistor unit 504, the sixth carbon nanotube transistor unit 506, the seventh carbon nanotube transistor unit 507 and the eighth carbon nanotube transistor unit 508 are all N-type carbon nanotube transistors.

[0086] The control terminal of the first carbon nanotube transistor unit 501 and the control terminal of the sixth carbon nanotube transistor unit 506 are connected as the input terminal IN of the tri-state gate circuit. The control terminals of the second carbon nanotube transistor unit 502 and the fourth carbon nanotube transistor unit 504 are connected to the enable signal terminal OE. The control terminals of the fifth carbon nanotube transistor unit 505 and the seventh carbon nanotube transistor unit 507 are connected to the disable signal terminal OEN. The drain of the third carbon nanotube transistor unit 503 and the drain of the eighth carbon nanotube transistor unit 508 are connected as the output terminal OUT of the tri-state gate circuit.

[0087] Figure 12 This is a schematic diagram of the structure of a carbon-based standard unit circuit in another embodiment of the present invention.

[0088] refer to Figure 12 The two or more carbon nanotube transistor units are connected to form a 2-2 input AND-OR-NOT gate circuit.

[0089] In a specific implementation, the two or more carbon nanotube transistor units include: a first carbon nanotube transistor unit 601, a second carbon nanotube transistor unit 602, a third carbon nanotube transistor unit 603, a fourth carbon nanotube transistor unit 604, a fifth carbon nanotube transistor unit 605, a sixth carbon nanotube transistor unit 606, a seventh carbon nanotube transistor unit 607, an eighth carbon nanotube transistor unit 608, a ninth carbon nanotube transistor unit 609, and a tenth carbon nanotube transistor unit 610.

[0090] The first carbon nanotube transistor unit 601, the second carbon nanotube transistor unit 602, the fifth carbon nanotube transistor unit 605, the sixth carbon nanotube transistor unit 606, and the ninth carbon nanotube transistor unit 609 are P-type carbon nanotube transistors, while the third carbon nanotube transistor unit 603, the fourth carbon nanotube transistor unit 604, the seventh carbon nanotube transistor unit 607, the eighth carbon nanotube transistor unit 608, and the tenth carbon nanotube transistor unit 610 are all N-type carbon nanotube transistors.

[0091] The control terminal of the first carbon nanotube transistor unit 601 is connected to the control terminal of the third carbon nanotube transistor unit 603, serving as the first input terminal IN1 of a 2-2 input AND-OR-NOT gate circuit. The control terminal of the second carbon nanotube transistor unit 602 is connected to the control terminal of the fourth carbon nanotube transistor unit 604, serving as the second input terminal IN2 of a 2-2 input AND-OR-NOT gate circuit. The control terminal of the fifth carbon nanotube transistor unit 605 is connected to the control terminal of the seventh carbon nanotube transistor unit 607, serving as the third input terminal IN3 of a 2-2 input AND-OR-NOT gate circuit. The control terminal of the sixth carbon nanotube transistor unit 606 is connected to the control terminal of the eighth carbon nanotube transistor unit 608, serving as the fourth input terminal IN4 of a 2-2 input AND-OR-NOT gate circuit. The drain of the ninth carbon nanotube transistor unit 609 is connected to the drain of the tenth carbon nanotube transistor unit 610, serving as the output terminal OUT of a 2-2 input AND-OR-NOT gate circuit.

[0092] Therefore, it can be seen that as long as one of the two or more carbon nanotubes connected in series in a carbon nanotube transistor unit can work properly, the circuit function of the carbon nanotube transistor unit can be realized. There is no need to remove the metallic carbon nanotubes in advance or use additional chemical solvents to remove the metallic carbon nanotubes, thus avoiding damage to the semiconducting carbon nanotubes, reducing process costs, and increasing the probability of the carbon nanotubes exhibiting semiconducting properties, thereby improving the performance of the carbon-based standard unit circuit.

[0093] Furthermore, the carbon nanotube transistor unit in this invention includes two or more carbon nanotube transistors connected in series, which is equivalent to a single carbon nanotube transistor in a prior art carbon nanotube transistor unit, ensuring the normal circuit function of the carbon nanotube transistor unit. Moreover, compared to a single carbon nanotube transistor in the prior art, the carbon nanotube transistor unit in this invention increases the number of carbon nanotube transistors, thereby reducing the probability of the carbon nanotube transistor unit malfunctioning.

[0094] Accordingly, the present invention also provides an integrated circuit comprising the carbon-based standard cell circuit described above. For example, the integrated circuit may include at least one of a first inverter circuit, a buffer, a tri-state gate circuit, and an AND-OR-NOT gate circuit.

[0095] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A carbon-based standard unit circuit, characterized in that, It includes at least one carbon nanotube transistor unit; the carbon nanotube transistor unit includes: Two or more carbon nanotube transistors connected in series; The carbon nanotubes contained in each carbon nanotube in the carbon nanotube transistor unit are different, the carrier conductivity type of each carbon nanotube in the carbon nanotube transistor unit is the same, and the gates of each carbon nanotube transistor are connected.

2. The carbon-based standard unit circuit as described in claim 1, characterized in that, At least one carbon nanotube in the carbon nanotube transistor unit is a semiconducting carbon nanotube.

3. The carbon-based standard unit circuit as described in claim 1 or 2, characterized in that, The carbon nanotube transistor unit includes a first carbon nanotube transistor and a second carbon nanotube transistor connected in series.

4. The carbon-based standard unit circuit as described in claim 1 or 2, characterized in that, In the same carbon nanotube transistor unit, each carbon nanotube is arranged along a first direction, which is perpendicular to the extension direction of the carbon nanotubes in the carbon nanotube transistor.

5. The carbon-based standard unit circuit as described in claim 1 or 2, characterized in that, The carbon-based standard unit circuit includes: two or more carbon nanotube transistor units; the carbon nanotube transistors in the two or more carbon nanotube transistor units are arranged along a first direction.

6. The carbon-based standard unit circuit as described in claim 5, characterized in that, The carbon-based standard unit circuit includes: a first carbon nanotube transistor unit and a second carbon nanotube transistor unit, wherein the carbon nanotube transistors in the first carbon nanotube transistor unit and the second carbon nanotube transistor unit are arranged along a first direction.

7. The carbon-based standard unit circuit as described in claim 6, characterized in that, The control terminal of the first carbon nanotube transistor unit is connected to the control terminal of the second carbon nanotube transistor unit to form a first inverter circuit.

8. The carbon-based standard unit circuit as described in claim 7, characterized in that, The carbon-based standard unit circuit further includes: a third carbon nanotube transistor unit and a fourth carbon nanotube transistor unit, wherein the control terminal of the third carbon nanotube transistor unit is connected to the control terminal of the fourth carbon nanotube transistor unit to form a second inverter circuit; the control terminal of the second inverter circuit is connected to the output terminal of the first inverter circuit.

9. The carbon-based standard unit circuit as described in claim 5, characterized in that, The two or more carbon nanotube transistor units are connected to form a NAND gate circuit.

10. The carbon-based standard unit circuit as described in claim 5, characterized in that, The number of carbon nanotube transistors is the same in each of the aforementioned carbon nanotube transistor units.

11. The carbon-based standard unit circuit as described in claim 1, characterized in that, In the carbon nanotube transistor unit, the charge carrier conduction type of each carbon nanotube transistor is either P-type or N-type.

12. An integrated circuit, characterized in that, Includes the carbon-based standard unit circuit according to any one of claims 1 to 11.

Images