Memory array, circuit, and method for fabricating memory device

Abstract

A memory array includes a continuous active region extending in one direction. The memory array includes a first bit cell, the first bit cell including a pair of first writing means and first reading means defined on the continuous active region. The memory array includes a first write word line coupled to a gate of the first writing means. The memory array includes a first read word line coupled to the gate of the pair of first reading means. The memory array includes a bit line, wherein a first of the pair of first reading means is coupled between a first source / drain node of the first writing means and the bit line.

Description

Attractive Multi-Transistor Antifuse Bit Cell Layout Structure in Power Performance Region Integrated circuits (ICs) sometimes include one-time-programmable (OTP) memories to provide non-volatile memory (NVM), where data is not lost when the IC is powered off. One type of OTP device includes antifuse memory. Antifuse memory includes multiple antifuse memory cells (or bit cells), whose ends are disconnected before programming and short-circuited (e.g., connected) after programming. Antifuse memory can be based on metal-oxide-semiconductor (MOS) technology. For example, an antifuse memory cell can include a programming MOS transistor (or MOS capacitor) and at least one reading MOS transistor coupled in series. The gate dielectric of the programming MOS transistor can be broken down to interconnect the gate and the source or drain of the programming MOS transistor. Depending on whether the gate dielectric of the programming MOS transistor is broken down, different data bits can be represented by the antifuse memory cell via reading the combined current flowing through the programming MOS transistor and the reading MOS transistor. Since the programmed state of the antifuse cell cannot be determined via reverse engineering, antifuse memory has the advantageous feature of being reverse-engineering proof. The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and configurations are described below to simplify the present disclosure. Of course, these are only examples and are not intended to be limiting. For example, in the following description, forming a first feature over or on a second feature can include embodiments where the first and second features are formed in direct contact, and can also include embodiments where additional features can be formed between the first and second features such that the first and second features are not in direct contact. Additionally, the present disclosure may repeat reference numerals and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate a relationship between the various embodiments and / or configurations discussed. In addition, for ease of description, spatial relative terms such as "under", "below", "lower", "over", "upper", "top", "bottom", and the like may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures. In addition to the orientation depicted in the figures, spatial relative terms are also intended to encompass different orientations of the device in use or operation. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein can be interpreted accordingly. A bit cell is the smallest unit of data storage in a digital memory device and can be fabricated using a circuit capable of storing a single information bit. A bit cell can be used to represent one of two logic states such as logic low (e.g., logic 0) and logic high (e.g., logic 1). Bit cells are configured in an array to form memory chips, which are used in various electronic devices and circuits for memory storage. An antifuse bit cell is a type of one-time programmable (OTP) bit cell that uses the dielectric breakdown phenomenon to store a single information bit. Dielectric breakdown is a process in which an insulating material such as a dielectric is subjected to a voltage breakdown so that the insulating material becomes conductive. Traditional methods for defining antifuse bit cells have led to several problems. For example, near the edge of the oxide defined (OD) region of a semiconductor material, the transistors of the bit cell are affected by the OD length (LOD) effect. The LOD effect is a phenomenon in which the electrical characteristics of the transistors constituting the bit cell are affected by the distance between the gate of the transistor and the edge of the OD region. The LOD effect can have a significant impact on the performance of the memory cell and is therefore undesirable. In addition, the traditional dual-transistor antifuse bit cell layout structure is not area-efficient, resulting in wasted space on the semiconductor die. Embodiments of the present disclosure utilize continuous active OD regions to define multi-transistor bit cells to eliminate the LOD effect, while improving device performance and reducing the total memory cell area. The techniques described herein utilize continuous active OD regions on which multiple bit cells can be defined. Each bit cell can include a pair of read devices and a write device defined therebetween. A dummy gate metal material layer can be provided near the edge of the continuous active region to eliminate the LOD effect, thereby improving device performance. In some embodiments, a voltage relaxation device can be included in the bit cell to reduce the impact of voltage stress during programming. By having multiple pairs of read transistors, various advantages regarding the read / write performance of the disclosed memory cells can be provided. For example, one of the read transistors in each pair is symmetrically disposed on both sides of the corresponding write transistor. Thus, when any write transistor has been previously programmed, the symmetrically coupled read transistors can significantly reduce the resistance value of the equivalent resistor (e.g., the programmed write transistor) coupled to the programmed resistor. FIG. 1A illustrates a block diagram of an exemplary layout 100A of bit cells 120 of a memory array according to some embodiments. The exemplary layout is a top-down layout, in which a plurality of contiguous active regions 102A and 102B are defined. The contiguous active regions 102A and 102B may sometimes be referred to herein as OD regions 102A and 102B. The OD regions 102A and 102B may comprise any suitable semiconductor material, such as silicon. Alternatively, the OD regions 102A and 102B may comprise other elemental semiconductor materials, such as (for example) germanium. The contiguous active regions 102A and 102B may also comprise compound semiconductors, such as silicon carbide, gallium arsenide, indium arsenide, and indium phosphide. The contiguous active regions 102A and 102B may comprise alloy semiconductors, such as silicon germanium, silicon carbide germanium, gallium arsenide phosphide, and gallium indium phosphide. In one embodiment, the contiguous active regions 102A and 102B comprise epitaxial layers. For example, the substrate may have an epitaxial layer covering the body semiconductor. Additionally, the contiguous active regions 102A and 102B may comprise a semiconductor-on-insulator (SOI) structure. As shown, each of the contiguous active regions 102A and 102B extends along the X direction as a single contiguous region of material, on which a writing device and a reading device (as described in further detail in connection with FIG. 1B) are defined. In the example shown in FIG. 1A, a bit cell 120 is formed by defining a first metal gate structure 104 for a first writing device (such as a write transistor). Two additional metal gate structures 106A and 106B are formed to define reading devices (such as read transistors) on either side of the writing device. Other details of the writing device and the reading device are described in connection with FIG. 1B. The first metal gate structure 104 and the read metal gate structures 106A and 106B are defined along a direction Y perpendicular to the direction X (for example, the contiguous active regions 102A and 102B extend along the direction Y). The gate metal may be separated from the contiguous active regions 102A and 102B by a thin layer of dielectric material, which may be a high-k dielectric material in some embodiments. Thus, the gate structures described herein may comprise multiple layers, such as a gate dielectric layer and a gate metal. Any suitable material may be used to form the gate metal of the gate structures described herein, including, for example, polysilicon (PO) or any other metal material described herein. As shown, the devices formed using the first metal gate structure 104 and the read metal gate structures 106A and 106B share source / drain regions. In this example, the write device includes source / drain regions shared with the corresponding source / drain regions of each of the read devices. These source / drain regions may each be coupled to a corresponding metal-diffusion layer 116, which may be used to route signals from the source / drain regions of the devices described herein to other circuits. Although not shown here, the first metal gate structure 104, the read metal gate structures 106A and 106B, and / or any metal-diffusion layer 116 may be coupled to various interconnects to couple the bit cell 120 to other logic circuits. The signals for activating the bit cell 120 (e.g., writing to and / or reading from the bit cell 120) are described in connection with FIG. 1B. As shown, the continuous active regions 102A and 102B may include one or more conductive vias 118 defined therethrough, which in this example are shown coupled to the external source / drain nodes of the read devices of each bit cell 120. The conductive vias 118 and any other metal materials described herein (including any gate metal, metal-diffusion layer, or interconnect metal) may be formed of aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof, or may otherwise include aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof. As described herein, the conductive vias may couple one or more of the source / drain nodes of a pair of read transistors to an interconnect (e.g., a corresponding bit line). Although two contiguous active regions 102A and 102B are shown herein, it should be understood that any number of contiguous active regions may be provided along the Z direction and any number of contiguous active regions may be formed in accordance with the techniques described herein to create a memory array of any suitable size. As shown, various materials in the layout are shown to be separated by a dielectric material 114 (e.g., an isolation structure). For example, regions of the dielectric material 114 electrically isolate the contiguous active region 102A from the contiguous active region 102B, thereby defining two columns of write and read devices as shown in that orientation. Additionally, the same regions of the dielectric material 114 may separate portions of the first metal gate structure 104 and the read metal gate structures 106A and 106B, thereby isolating the gate structures (and the devices formed therefrom) on the contiguous active region 102A from the gate structures formed on the contiguous active region 102B. In some embodiments, the dielectric material 114 may only isolate the contiguous active regions 102A and 102B from each other and not from the first metal gate structure 304 and the read metal gate structures 106A and 106B, thereby enabling the devices formed on each of the contiguous active regions 102A and 102B to share gate metal. Example dielectric materials for forming regions of the dielectric material may include, but are not limited to, oxide materials or other non-conductive materials (e.g., isolators). In this example configuration, three bit cells 120 are shown on each of the contiguous active regions 102A and 102B, thereby forming a total of six depicted bit cells 120. The first metal gate structure 104 and the read metal gate structures 106A and 106B form the upper left bit cell 120 on the contiguous active region 102A and the lower left bit cell on the contiguous active region 102B. The second metal gate structure 106 and the second read metal gate structures 108A and 108B form the top middle bit cell 120 on the contiguous active region 102A and the bottom middle bit cell on the contiguous active region 102B. The third metal gate structure 110 and the second read metal gate structures 112A and 112B form the upper right bit cell 120 on the contiguous active region 102A and the lower right bit cell on the contiguous active region 102B. Although three bit cells 120 are shown on each of the contiguous active regions 102A and 102B, it should be understood that any number of bit cells may be formed by providing corresponding metal gate layers, metal-diffusion layers, and conductive vias along the X direction. An example circuit diagram showing the electrical connections between each of the write and read devices of the bit cell 120 is shown in FIG. 1B. Referring to FIG. 1B, an example circuit diagram 100B of a portion of a memory array shown by layout 100A of FIG. 1A is illustrated according to some embodiments. In the illustrated example of FIG. 1B, anti-fuse bit cells 120A, 120B, 120C, 120D, 120E, and 120F are shown. Although six anti-fuse memory cells 120A - F are shown, it should be understood that the memory array can have any number of anti-fuse memory cells while still being within the scope of this disclosure. Bit cells 120A - 120F can be configured in an array as shown in FIG. 1A. In FIG. 1B, bit cells 120A, 120B, and 120C can be disposed in the same column (e.g., defined on the same continuous active region such as continuous active region 102A as shown in FIG. 1A), but in respectively different rows. Bit cells 120D, 120E, and 120F can be disposed in the same column (e.g., defined on continuous active region 102B as shown in FIG. 1A), but in respectively different rows. With this configuration, each of the bit cells can be operatively coupled to access lines in the corresponding column and row (e.g., WLP0, WLR0, WLP1, WLR1, WLP2, WLR2, BL0, BL1, etc.). For example, in FIG. 1B, bit cell 120A and bit cell 120D are operatively coupled to a first write word line WLP0, a first read word line WLR0, and bit line BL0. Bit cell 120A is operatively coupled to bit line BL0, while bit cell 120D is operatively coupled to bit line BL1. Bit cells 120B and 120E are operatively coupled to a second write word line WLP1 and a second read word line WLR1. Bit cell 120B is operatively coupled to bit line BL0, while bit cell 120E is operatively coupled to bit line BL1. Bit cells 120C and 120F are operatively coupled to a third write word line WLP2 and a third read word line WLR2. Bit cell 120C is operatively coupled to bit line BL0, while bit cell 120F is operatively coupled to bit line BL1. Each of the access lines (e.g., WLP0, WLR0, WLP1, WLR1, WLP2, WLR2, BL0, BL1, etc.) is operatively coupled to a corresponding I / O circuit that transmits a corresponding signal to select bit cell 120 for write or read operations. These operations can be performed by applying a predetermined pattern of logical selection to each of the access lines. In the following discussion of such operations, bit cell 120A is selected as a representative example. As shown in FIG. 1B, the bit cell 120A includes a write device 122 (sometimes referred to as a write transistor 122) and a pair of read devices 124A and 124B (sometimes referred to as a pair of read transistors 124A and 124B). The write transistor 122 is serially coupled to the read transistors 124A and 124B respectively. One source / drain terminal of the write transistor 122 is serially coupled to the source / drain terminal of one of the corresponding pair of read transistors 124A and 124B; and the other source / drain terminal of the write transistor 122 is serially coupled to the source / drain terminal of the other of the corresponding pair of read transistors 124A and 124B. The other source / drain terminals of the read transistors 124A and 128B are commonly coupled to nodes 126A and 126B, which connect these source / drain terminals to the bit line BL0. Nodes 126A and 126B are also operatively connected to the source / drain terminals of the read devices of an adjacent bit cell 120. In this example, as shown, node 126B is operatively coupled to the read device of bit cell 120B. As shown, the write transistor 122 is gated by a write line WLP0 (e.g., the gate terminal of the write transistor 122 is coupled to WLP0). The read transistors 124A and 124B are gated by a read line WLR0 (e.g., the respective gate terminals of the read transistors 124A and 124B are coupled to the read line WLR0). Each of the other bit cells (e.g., 120B, 120C, 120D, 120E, 120F) can be configured to be substantially similar to the bit cell 120A. Therefore, the bit cells 120B to 120F are briefly described as follows. The bit cell 120D includes a bit cell also gated by the write line WLP0. The bit cells 120B and 120E include write devices gated by the write line WLP1. The bit cells 120C and 120F each include a write device gated by WLP2. In some embodiments, the write / read devices of the bit cells 120A to 120F can include n-type metal oxide semiconductor field effect transistors (n-type MOSFETs) or sometimes referred to as NMOS transistors. However, it should be understood that each of the write / read devices can include p-type metal oxide semiconductor field effect transistors (p-type MOSFETs) while still being within the scope of this disclosure. It should be understood that the write / read devices described herein can include or otherwise be any type of transistor or switching device suitable for a bit cell. To program bit cell 120A, read transistors 124A and 124B are turned on by supplying a voltage high enough (e.g., a positive voltage corresponding to a logic high state) to their respective gate terminals via read line WLR0. Before, simultaneously with, or after read transistors 124A to 124B are turned on, a voltage high enough (e.g., a breakdown voltage (VBD), sometimes referred to as a programming voltage) is applied to programming line WLP0, and a voltage low enough (e.g., a positive voltage corresponding to a logic low state or a ground voltage) is applied to bit line BL0. The low voltage (applied to bit line BL0) can be transferred to the source / drain terminals of programming device 122. Thus, the programming voltage VBD can be present on both the source terminal and the gate terminal of programming transistor 122 and on both the drain terminal and the gate terminal of programming transistor 122. The breakdown voltage on these terminals causes the gate dielectric layer of programming device 122 to break down. After the gate dielectric layer of programming device 122 breaks down, the electrical behavior of the portion of the gate dielectric layer that interconnects the gate terminal and its source / drain terminals is resistive. For example, this portion of the gate dielectric layer of programming transistor 122 can act as a resistor. Before the programming operation (e.g., before the gate dielectric layer of any of programming transistors 122 breaks down), even when read devices 124A and 124B are turned on, there is no conductive path between bit line BL0 and programming line WLP0. After the programming operation has been completed, when read devices 124A and 124B are turned on, there is a conductive path between bit line BL0 and programming line WLP0 (e.g., via the broken-down programming transistor 122, which operates as a resistor). When programming transistor 122 breaks down, a conductive path is established, and a sudden increase in voltage can be present on the source terminal and the drain terminal of programming transistor 122, which can cause a sudden increase in the voltage on bit line BL0. Thus, the voltage levels at the source terminal and the drain terminal of programming transistor 122 can be increased such that the programming process on transistor 122 can automatically stop (as the voltage drop between its gate and source terminals decreases). Thus, bit cell 120A can be programmed to a first logic state or a second logic state. In some embodiments, the read process of bit cell 120A may include simultaneously applying a relatively low-level voltage (sometimes referred to as a read voltage) on the gate of write device 122. If write transistor 122 is broken down, an observable decrease in the read voltage may exist on the broken-down write transistor 122. In contrast, if write transistor 122 is not broken down, the read voltage applied on the non-broken-down write transistor may remain substantially unchanged. In an example where write transistor 122 is broken down, an observable drop in the read voltage applied on WLP0 can be detected. Accordingly, the logic state of cell 120A can be determined. A similar method can be used to program any of bit cells 120B to 120F by, for example, applying corresponding voltage signals to corresponding bit lines BL0 or BL1, corresponding write lines WLP0, WLP1 or WLP2, and corresponding read lines WLR0, WLR1 or WLR2 to break down the desired write device. Referring to FIG. 2A, a cross-sectional layout diagram 200A is illustrated, which shows an example bit cell 240 similar to bit cell 120 described in connection with FIGS. 1A and 1B. In this example, cross-sectional layout diagram 200A shows a front-side metal layer formed to couple to write and read devices of bit cell 240 defined on continuous active region 202. In this example, continuous active region 202 may be similar to one of continuous active regions 102A or 102B, as described in connection with FIGS. 1A and 1B. Although two bit cells 240 are shown in this example, it should be understood that continuous active region 202 may include any number of bit cells defined thereon. Similarly, bit cell 240 defined on continuous active region 202 may include any number of transistors, including bit cells having more than three transistors, as described in connection with FIGS. 3A to 5B. Bit cell 240 is shown to include a write device gate structure 204 that may be similar to gate structure 104 of FIG. 1A. Write device gate structure 204 is positioned between two read device gate structures 208A and 208B, and two read device gate structures 208A and 208B may be similar to the pair of read device gate structures 106A and 106B of FIG. 1A. As shown, metal-diffusion regions 214 are formed on continuous active region 202 such that one of metal-diffusion regions 214 is formed on the source / drain terminal of the read device having read device gate structure 208A, and the other of metal-diffusion regions 214 is formed on the source / drain terminal of the read device having read device gate structure 208B. FIG. 1A also depicts gate structures 206, 210A, 210B, and 228. The metal-diffusion region 214 is shown as being coupled to corresponding conductive vias 216, which are operatively coupled to the metal-diffusion region 214 (and thus to the source / drain terminals of the read device). As indicated by the curves in Figure 2A, any number of interconnect layers (each of which may include a corresponding metal layer) may be coupled to one or more of the metal-diffusion regions 214 to implement the desired logic for read and write operations, as described herein. In this example, three metal layers 218, 220, and 224 are shown, each of which is connected to various structures in the material stack forming the bit cell 240 via corresponding conductive vias. For example, the metal layer 218 is coupled to the metal-diffusion region 214 via the conductive via 216, and the metal layer 220 (which is patterned in this cross-sectional view to have several portions perpendicular to the metal layer 218) is coupled to the metal layer 216 using the conductive via 219. Additionally, the third metal layer 224 is shown as being coupled to the second metal layer 220 using the conductive via 222. Each of the three metal layers 218, 220, and 224 may be patterned such that they can operate as one or more of the corresponding bit lines BL0 and / or BL1 described in connection with Figures 1A to 1B. Although not shown here, one or more metal layers may be provided to be coupled to (e.g., using one or more conductive vias) the write device gate structure 204 to provide a write voltage (e.g., VDB) or a read voltage. Similarly, although not shown here, one or more metal layers may be provided to be coupled to each of the gate structures 208A and 208B of the read device to enable reading and writing of the device. In this example, each of the layers is formed via front-side metallization, where the metal layers are deposited on the front side of the device (e.g., upward in the Y direction). An example including both front-side metallization and back-side metallization is shown in Figure 2B. Figure 2B illustrates a cross-sectional layout diagram 200B, which depicts the memory device shown in Figure 2A after back-side metallization. As shown, in addition to the front-side metal layers 218, 220, and 224 described in connection with Figure 2A, the memory device is depicted as including back-side metal layers 232 and 236 that may be formed via a back-side metallization process. Each of the front-side metallization process for forming the front-side metal layers 218, 220, and 224 and the back-side metallization process for forming the back-side metal layers 232 and 236 may include cleaning, deposition, patterning, and planarization processes. Although not shown here for visual clarity, the blank gaps between each of the layers formed in the material layers may include dielectric materials. In this example, the first backside metal layer 232 is operatively coupled to the metal-diffusion region 214 via the backside vias (VB) 230. The backside vias 230 can be formed by creating conductive regions through the entire continuous active region. As shown, the backside vias 230 are coupled to the metal-diffusion region 214. In this example, the second backside metal layer 236 is operatively coupled to the metal-diffusion region 214 using corresponding conductive vias 234. Although two backside metal layers 232 and 236 are shown here, it should be understood that any number of backside metal layers can be provided to achieve the desired logic functionality. In some embodiments, the backside metal layers may not be utilized, and only front-side metallization may be performed, as shown in FIG. 2A. The cross-sectional layout 200B also shows the region of the continuous active region 202 corresponding to the source / drain regions 231 (sometimes referred to herein as "epitaxial structures 231"). The source / drain regions 231 can include epitaxial structures that operate as the source / drain of the corresponding transistors described herein. The source / drain regions 231 can be defined to form N-type or P-type devices. For example, N-type and P-type FETs can be formed by implanting different types of dopants into the source / drain regions 231 of the continuous active region 202 of the device to form the necessary junction surfaces. The source / drain regions 231 can be defined as regions where no gate structure exists. In one example, an N-type device can be formed by implanting arsenic (As) or phosphorus (P), and a P-type device can be formed by implanting boron (B). In some embodiments, the continuous active region 202 is formed in a stacked structure protruding from the main surface of the substrate. The stack can include a plurality of semiconductor nanostructures (such as nanosheets) extending along the X direction and vertically separated from each other. The portions of the semiconductor structures in the stack covered by the gate structures (such as gate structures 204, 208A - 208B, etc.) are retained, while other portions are replaced with a plurality of epitaxial structures 231. The remaining portions of the semiconductor structures (such as those under the gate structures) can be configured as the channels of the corresponding transistors, the epitaxial structures coupled to both sides (or ends) of the remaining portions of the semiconductor structures can be configured as the source / drain structures (or ends) of the transistors, and the portions of the gate structures (such as gate structures 204, 208A - 208B) covering (such as across) the remaining portions of the semiconductor structures can be configured as the gate structures (or ends) of the transistors. For example, in FIG. 2B, the portion of the continuous active region 202 covered by the gate structure 204 may include a plurality of nanostructures vertically separated from each other, and these nanostructures may serve as the channel of the first transistor. As shown, the portion of the continuous active region 202 disposed on the opposite side of the gate structure 204 is replaced with an epitaxial structure 231. To further illustrate this example, such an epitaxial structure 231 may serve as the source / drain terminal of the write transistor 122 (the "D" and "S" in FIG. 1B). The gate structure may serve as the gate terminal of the write transistor 122 (the "G" in FIG. 1B). Referring to FIG. 3A, a block diagram of an exemplary layout 300A of a bit cell 320 of a memory array including a voltage relaxation device according to some embodiments is illustrated. Similar to the layout shown in FIG. 1A, the layout 300A is a top-down layout, in which a plurality of continuous active regions 302A and 302B are defined. The continuous active regions 302A and 302B may sometimes be referred to herein as OD regions 302A and 302B. The continuous active regions 302A and 302B may be similar to the continuous active regions 102A and 102B of FIG. 1A and may include any suitable semiconductor material, such as silicon or any other type of semiconductor material described herein. As shown, each of the continuous active regions 302A and 302B extends along the X direction as a single continuous region of material, on which a write device and a read device are defined (as described in further detail in conjunction with FIG. 3B). In the example shown in FIG. 3A, a bit cell 320 is formed by defining a first metal gate structure 304 for a first write device (such as a write transistor). Two gate structures 306A and 306B are formed to define voltage relaxation devices (such as voltage relaxation transistors) on either side of the write device. As shown, additional metal gate structures 308A and 308B are also formed to define read devices (such as read transistors) on either side of the voltage relaxation devices, such that the voltage relaxation devices are each positioned between the respective read devices and the write device. Other details of the write device, the voltage relaxation device, and the read device are described in conjunction with FIG. 3B. The first metal gate structure 304, the voltage relaxation gate structures 306A and 306B, and the read metal gate structures 308A and 308B are defined along a direction Y perpendicular to the direction X (for example, the continuous active regions 302A and 302B extend along the direction Y). The gate metal may be separated from the continuous active regions 302A and 302B by a thin layer of dielectric material, which may be a high-k dielectric material in some embodiments. Thus, the gate structures described herein may include multiple layers, such as a gate dielectric layer and a gate metal. Any suitable material may be used to form the gate metal of the gate structures described herein, including, for example, PO or any other metal material described herein. As shown, devices formed using the first metal gate structure 304 (sometimes referred to as the write metal gate structure 304) and the voltage relaxation metal gate structures 306A and 306B share source / drain regions. Similarly, each of the voltage relaxation devices shares respective source / drain regions with an adjacent one of the read devices. As shown, the source / drain regions of each of the voltage relaxation devices and each of the read devices may be coupled to corresponding metal-diffusion layers 316. The metal-diffusion layers 316 may be similar to the metal-diffusion layer 116 of FIG. 1A and may be used to route signals from the source / drain regions of the devices described herein to other circuits. Although not shown here, the write metal gate structure 304, the voltage relaxation metal gate structures 306A and 306B, and the read metal gate structures 308A and 308B and / or any metal-diffusion layers 316 may be coupled to various interconnects to couple the bit cell 320 to other logic circuits. Signals for activating the bit cell 320 (e.g., writing to and / or reading from the bit cell 320) are described in connection with FIG. 3B. As shown, the continuous active regions 302A and 302B may include one or more conductive vias 322 defined therethrough, which in this example are shown coupled to the external source / drain nodes of the read devices of each bit cell 320. The conductive vias 322 and any other metal materials described herein (including any gate metals, metal-diffusion layers, or interconnect metals) may be formed of aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof, or may otherwise include aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof. As described herein, the conductive vias may couple one or more of the source / drain nodes of a pair of read transistors to an interconnect (such as a corresponding bit line). Although two contiguous active regions 302A and 302B are shown herein, it should be understood that any number of contiguous active regions extending continuously along the X direction may be provided along the Z direction as shown, and any number of contiguous active regions may be formed in accordance with the techniques described herein to create a memory array of any suitable size. As shown, the various materials in layout 300A are shown to be separated by dielectric material 318. For example, regions of dielectric material 318 electrically isolate contiguous active region 302A from contiguous active region 302B, thereby defining two columns of write and read devices as shown by the orientation. Additionally, the same regions of dielectric material 318 may separate portions of first metal gate structure 304, voltage relaxation gate structures 306A and 306B, and read metal gate structures 308A and 308B, thereby isolating the gate structures (and the devices formed thereby) on contiguous active region 302A from the gate structures formed on contiguous active region 302B. In some embodiments, dielectric material 318 may only isolate contiguous active regions 302A and 302B from each other, rather than isolating them from first metal gate structure 304, voltage relaxation gate structures 306A and 306B, and read metal gate structures 308A and 308B, such that the devices formed on each of contiguous active regions 302A and 302B can share gate metal. In this example configuration, two bit cells 320 are shown on each of contiguous active regions 302A and 302B, thereby forming a total of four depicted bit cells 320. First metal gate structure 304, voltage relaxation metal gate structures 306A and 306B, and read metal gate structures 308A and 308B form the upper left bit cell 320 on contiguous active region 302A and the lower left bit cell on contiguous active region 302B. Second metal gate structure 310, second voltage relaxation gate structures 312A and 312B, and second read metal gate structures 314A and 314B form the upper right bit cell 320 on contiguous active region 302A and the lower right bit cell on contiguous active region 302B. Although two bit cells 320 are shown on each of contiguous active regions 302A and 302B, it should be understood that any number of bit cells may be formed by providing corresponding metal gate layers, metal-diffusion layers, and conductive vias along the X direction. An example circuit diagram showing the electrical connections between each of the write and read devices of bit cell 320 is shown in FIG. 3B. Referring to FIG. 3B, an example circuit diagram 300B of a portion of a memory array corresponding to the layout 300A of FIG. 3A is illustrated according to some embodiments. In the illustrated example of FIG. 3B, antifuse bit cells 320A, 320B, 320C, and 320D are shown. Although four antifuse memory cells 320A-320D are shown, it should be understood that the memory array may have any number of antifuse memory cells while still being within the scope of the present disclosure. The bit cells 320A-320D may be configured in an array as shown in FIG. 3A. In FIG. 3B, bit cells 320A and 320B may be disposed in the same column (e.g., defined on the same continuous active region such as continuous active region 302A as shown in FIG. 3A), but in respectively different rows. Bit cells 320C and 320D may be disposed in the same column (e.g., defined on continuous active region 302B as shown in FIG. 3A), but in respectively different rows. With this configuration, each of the bit cells may be operatively coupled to access lines in corresponding columns and rows (e.g., WLP0, WLB0, WLR0, WLP1, WLB1, WLR1, BL0, BL1, etc.). For example, in FIG. 3B, bit cell 320A and bit cell 320C are operatively coupled to a first write character line WLP0, a first voltage relaxation character line WLB0, a first read character line WLR0, and bit line BL0. Bit cell 320A is operatively coupled to bit line BL0, while bit cell 320C is operatively coupled to bit line BL1. Bit cell 320B and bit cell 320C are operatively coupled to a second write character line WLP1, a second voltage relaxation character line WLB1, and a second read character line WLR1. Bit cell 320B is operatively coupled to bit line BL0, while bit cell 320C is operatively coupled to bit line BL1. Each of the access lines (e.g., WLP0, WLB0, WLR0, WLP1, WLB1, WLR1, BL0, BL1, etc.) is operatively coupled to a corresponding I / O circuit that transmits a corresponding signal to select the bit cell 320 for a write or read operation. These operations may be performed by applying a predetermined pattern of logical selection to each of the access lines. In the following discussion of such operations, bit cell 320A is selected as a representative example. As shown in FIG. 3B, bit cell 320A includes a write device 324 (sometimes referred to as write transistor 324), a pair of voltage relaxation devices 326A and 326B (sometimes referred to as a pair of voltage relaxation transistors 326A and 326B), and a pair of read devices 328A and 328B (sometimes referred to as a pair of read transistors 328A and 328B). As shown, write transistor 324 and voltage relaxation transistors 326A and 326B are connected in series, and these transistors are respectively coupled in series to read transistors 328A and 328B. One source / drain terminal of write transistor 324 is serially coupled to the corresponding source / drain terminal of one of the pair of voltage relaxation transistors 328A and 328B; and the other source / drain terminal of write transistor 324 is serially coupled to the corresponding source / drain terminal of the other of the pair of voltage relaxation transistors 328A and 328B. As shown, one source / drain terminal of voltage relaxation transistor 326A is serially coupled to the source / drain terminal of read transistor 328A; and the source / drain terminal of voltage relaxation transistor 326B is serially coupled to the source / drain terminal of read transistor 328B. The other source / drain terminals of read transistors 328A and 328B are commonly coupled to nodes 330A and 330B, which connect these source / drain terminals to bit line BL0. Nodes 330A and 330B are also operatively connected to the source / drain terminals of the read devices of adjacent bit cell 320. In this example, as shown, node 330B is operatively coupled to the read device of bit cell 320B. As shown, write transistor 324 is gated by write line WLP0 (e.g., the gate terminal of write transistor 324 is coupled to WLP0). Voltage relaxation transistors 326A and 326B are gated by voltage relaxation word line WLB0 (e.g., the respective gate terminals of voltage relaxation transistors 326A and 326B are coupled to voltage relaxation word line WLB0). Read transistors 328A and 328B are gated by read line WLR0 (e.g., the respective gate terminals of read transistors 328A and 328B are coupled to read line WLR0). Each of the other bit cells (e.g., 320B, 320C, 320D) can be configured to be substantially similar to bit cell 320A. Thus, bit cells 320B to 320D are briefly described as follows. Bit cell 320C includes a bit cell also gated by write line WLP0. Bit cells 320B and 320D include write devices gated by write line WLP1. In some embodiments, the write devices, voltage relaxation devices, and read devices of bit cells 320A - 320D may include n-type metal-oxide-semiconductor field-effect transistors (n-type MOSFETs), or sometimes referred to as NMOS transistors. However, it should be understood that each of the write / read devices may include p-type metal-oxide-semiconductor field-effect transistors (p-type MOSFETs) and still be within the scope of this disclosure. It should be understood that the write / read devices described herein may include or otherwise be any type of transistor or switching device suitable for a bit cell. To write to bit cell 320A, voltage relaxation transistors 326A and 326B and read transistors 328A and 328B are turned on by supplying a voltage high enough (e.g., a positive voltage corresponding to a logic high state) to their respective gate terminals via voltage relaxation word line WLB0 and read word line WLR0. Before, simultaneously with, or after voltage relaxation transistors 326A and 326B and read transistors 328A and 328B are turned on, a voltage high enough (e.g., VBD) is applied to write line WLP0, and a voltage low enough (e.g., a positive voltage corresponding to a logic low state or a ground voltage) is applied to bit line BL0. Including pairs of voltage relaxation transistors 326A and 326B between the write resistor 324 and pairs of read transistors 328A and 328B reduces the total high voltage stress on each device during a write operation. The low voltage (applied to bit line BL0) can be transferred to the source / drain terminals of write device 324. Thus, the write voltage VBD can be present simultaneously on the source terminal and the gate terminal of write transistor 324 and on the drain terminal and the gate terminal of write transistor 324. The breakdown voltage at these terminals causes the gate dielectric layer of write device 324 to break down, causing it to act as a resistor, as described in connection with FIG. 1A. As described herein, when write transistor 324 breaks down, a conductive path is established, and a sudden increase in voltage may exist at the source and drain terminals of write transistor 324, which can cause a sudden increase in the voltage on bit line BL0. Therefore, the voltage levels at the source and drain terminals of write transistor 324 can be increased such that the write process on transistor 324 can automatically stop (as the voltage drop between its gate and source terminals decreases). Thus, bit cell 320A can be written to a first logic state or a second logic state. In some embodiments, the read process of bit cell 320A may include simultaneously applying a relatively low-level voltage (sometimes referred to as a read voltage) to the gate of write device 324. If write transistor 324 is broken down, an observable decrease in the read voltage may exist across the broken-down write transistor 324. In contrast, if write transistor 324 is not broken down, the read voltage applied across the non-broken-down write transistor may remain substantially unchanged. In an example where write transistor 324 is broken down, an observable drop in the read voltage applied to WLP0 can be detected. Accordingly, the logic state of cell 320A can be determined. A similar method can be utilized to program any of bit cells 320B to 320D, for example, by applying corresponding voltage signals to corresponding bit lines BL0 or BL1, corresponding write lines WLP0 or WLP1, corresponding voltage relaxation lines WLB0 and WLB1, and corresponding read lines WLR0 or WLR1 to break down the desired write device. Referring to FIG. 4A, a block diagram of an example layout 400A of an example bit cell 420 of a memory array including multiple write devices according to some embodiments is illustrated. Similar to the layouts shown in FIGS. 1A and 3A, layout 400A is a top-down layout, in which multiple consecutive active regions 402A and 402B are defined. Consecutive active regions 402A and 402B may sometimes be referred to herein as OD regions 402A and 402B. Consecutive active regions 402A and 402B may be similar to the consecutive active regions 102A and 102B of FIG. 1A and may include any suitable semiconductor material, such as silicon or any other type of semiconductor material described herein. As described in connection with FIGS. 1A and 3A, each of consecutive active regions 402A and 402B extends along the X direction as a single continuous region of material, on which write devices and read devices are defined (as described in further detail in connection with FIG. 4B). In the example shown in FIG. 4A, bit cell 420 is formed by defining metal gate structures 404A and 404B, each corresponding to a respective write device (e.g., write transistors sharing a source / drain region and connected in series). Four voltage relaxation gate structures 406A, 406B, 406C, and 406D are formed to define a set of four voltage relaxation devices (e.g., four voltage relaxation transistors) on either side of two write devices. As shown, four additional read gate structures 408A, 408B, 408C, and 408D are also formed to define four read devices (e.g., read transistors) on either side of respective pairs of voltage relaxation devices surrounding a pair of write devices, such that two voltage relaxation devices are each positioned between a respective read device and a write device. Other details of the write devices, voltage relaxation devices, and read devices are described in connection with FIG. 4B. Except for each of the two devices configured as defined in the layout 100A shown in FIG. 1A, the configuration shown in FIG. 4A is structurally similar to the example shown in FIG. 1A. For example, the layout 400A includes a dielectric material 418, which may be similar to the dielectric material 114 of FIG. 1A and may electrically isolate the continuous active regions 402A and 402B from each other and from other components of the circuit. Additionally, the write device, voltage relaxation device, and read device defined by write gate structures 404A-404B, voltage relaxation gate structures 406A-406D, and read gate structures 408A-408D respectively each include a corresponding source / drain structure. In this example, each of the source / drain structures is shown coupled to a respective metal-diffusion layer 416, which may be similar to the metal-diffusion layer 116 of FIG. 1A. Each of the continuous active regions 102A and 102B may include one or more conductive vias 422 defined therethrough, which in this example are shown coupled to the external source / drain nodes of the outermost read device of each bit cell 120. Although two continuous active regions 102A and 102B are shown here, it should be understood that any number of continuous active regions may be provided along the Z direction and any number of continuous active regions may be formed according to the techniques described herein to create a memory array of any suitable size. Similarly, any number of bit cells 420 may be defined along the continuous active regions 402A and 402B by providing corresponding gate structures, metal-diffusion layers, and conductive vias in a pattern similar to the pattern shown in the layout 400A. In this example, two bit cells 420 are shown, one bit cell 420 formed on the active region 402A and the other bit cell 420 formed on the active region 402B. An example circuit diagram showing the electrical connections between each of the write and read devices of the bit cell 120 is shown in FIG. 1B. Referring to FIG. 4B, an example circuit diagram 400B of a portion of a memory array corresponding to the layout 400A of FIG. 4A is illustrated according to some embodiments. In the illustrated example of FIG. 4B, one antifuse bit cell 420 is shown, and the second antifuse bit cell shown in the layout 400A is omitted for visual clarity. Although one antifuse bit cell 420 is shown, it should be understood that the memory array may have any number of antifuse bit cells while still being within the scope of this disclosure. The bit cell 420 can be defined as the portion of the memory array that is located in the corresponding column and row relative to other bit cells. With this configuration, each of the bit cells can be operatively coupled to the access lines in the corresponding column and row, respectively. In FIG. 4B, the bit cell 420 is operatively coupled to the write character line WLP0, the voltage relaxation character line WLB0, the read character line WLR0, and the bit line BL0. Each of the access lines (such as WLP0, WLB0, WLR0, BL0, etc.) is operatively coupled to the corresponding I / O circuit, and the corresponding I / O circuit transmits the corresponding signal to the selected bit cell 420 for write or read operations. These operations can be performed by applying a predetermined pattern of logical selection to each of the access lines. The bit cell 420 includes two pairs of write devices 424A (sometimes referred to as write transistors 424), two pairs of voltage relaxation devices 426A, 426B, 426C, and 426D (sometimes referred to as voltage relaxation transistors 426A, 426B, 426C, and 426D), and two pairs of read devices 428A, 428B, 428C, and 428D (sometimes referred to as read transistors 428A, 428B, 428C, and 428D). The pair of write transistors 424A and 424B are connected in series. As shown, the first write transistor 424A is serially coupled to the first pair of voltage relaxation transistors 426A and 426B in series, and the second write transistor 424B is serially coupled to the second pair of voltage relaxation transistors 426C and 426D. As shown, the first pair of voltage relaxation transistors 426A~426B are serially coupled to the first pair of read transistors 428A~428B, and the second pair of voltage relaxation transistors 426C~426D are serially coupled to the second pair of read transistors 428C~428D. As shown, each of these devices shares a source / drain terminal. The external source / drain terminals of read transistors 428A and 428D are commonly coupled to nodes 430A and 430B, which connect these source / drain terminals to bit line BL0. Nodes 430A and 430B are also operatively connected to the source / drain terminals of the read devices of adjacent bit cells 420. As shown, write transistors 424A and 424B are gated by write line WLP0 (e.g., the gate terminals of write transistors 424A and 424B are coupled to WLP0). Voltage relaxation transistors 426A, 426B, 426C, and 426D are gated by voltage relaxation word line WLB0 (e.g., the respective gate terminals of voltage relaxation transistors 426A, 426B, 426C, and 426D are coupled to voltage relaxation word line WLB0). Read transistors 428A, 428B, 428C, and 428D are gated by read line WLR0 (e.g., the respective gate terminals of read transistors 428A, 428B, 428C, and 428D are coupled to read line WLR0). In some embodiments, the write devices, voltage relaxation devices, and read devices of bit cells 320A - 320D may include n-type metal oxide semiconductor field effect transistors (n-type MOSFETs) or sometimes referred to as NMOS transistors. However, it should be understood that each of the write / read devices may include p-type metal oxide semiconductor field effect transistors (p-type MOSFETs) and still be within the scope of this disclosure. It should be understood that the write / read devices described herein may include or otherwise be any type of transistor or switching device suitable for a bit cell. To write to bit cell 420, an operation similar to the operation described in connection with FIG. 1B may be performed using a write voltage applied to write line WLP0, while turning on voltage relaxation transistors 426A - 426D and read transistors 428A - 428D, and applying a logic low state to bit line BL0. This causes write transistors 424A and 424B to break down and change their electrical behavior to act as resistors. The read process of bit cell 420 may be similar to the read process described in connection with FIG. 1A and may include applying a relatively low level voltage (sometimes referred to as a read voltage) to the gates of write devices 424A and 424B simultaneously. In some embodiments, the write voltage applied to WLP0 during a write operation may be between about 3V and about 5V, while the read voltage applied to WLP0 during a read operation may be between about 0.9V and about 1.5V. In some embodiments, the write voltage applied to WLR0 during a write operation may be between about 0.9V and about 1.5V, while the read voltage applied to WLR0 during a read operation may be between about 0.5V and about 0.9V. The voltage applied to WLB0 during a write operation may be between the voltages applied to WLP0 and WLR0 and may be between about 1V and about 4.5V. In some embodiments, during a read operation, the read voltage applied to WLB0 may be between about 0.5V and about 0.9V. In some embodiments, if a particular line is not selected (e.g., bit cell 420 is not being written or read), the unselected voltage applied to the line may be less than about 0.5V. Referring to FIG. 5A, a block diagram of an exemplary layout 500A of a bit cell 520 of a memory array including a plurality of pairs of voltage relaxation devices and a single write device according to some embodiments is illustrated. Similar to the layouts shown in FIGS. 1A, 3A, and 4A, layout 500A is a top-down layout in which a plurality of continuous active regions 502A and 502B are defined. The continuous active regions 502A and 502B may sometimes be referred to herein as OD regions 502A and 502B. The continuous active regions 502A and 502B may be similar to the continuous active regions 102A and 102B of FIG. 1A and may comprise any suitable semiconductor material, such as silicon or any other type of semiconductor material described herein. As described in connection with FIGS. 1A, 3A, and 4A, each of the continuous active regions 502A and 502B extends along the X direction as a single continuous region of material, on which a writing device and a reading device (as described in further detail in connection with FIG. 5B) are defined. In the example shown in FIG. 5A, a bit cell 520 is formed by defining a first metal gate structure 504 for a first writing device (e.g., a writing transistor). Two first voltage relaxation gate structures 506A and 506B are formed as a first pair that defines voltage relaxation devices (e.g., first voltage relaxation transistors) on either side of the writing device. As shown, two second voltage relaxation gate structures 508A and 508B are formed as a second pair that defines voltage relaxation devices (e.g., second voltage relaxation transistors) on either side of the writing device, where these voltage relaxation devices are each positioned in series with a respective one of the first pair of voltage relaxation devices. As shown, additional metal gate structures 510A and 510B are also formed to define reading devices (e.g., reading transistors) on either side of the second voltage relaxation devices, such that the first voltage relaxation devices and the corresponding second voltage relaxation devices are each positioned between a respective reading device and the writing device. Additional details of the writing device, the voltage relaxation devices, and the reading device are described in connection with FIG. 5B. A writing gate structure 504, first voltage relaxation gate structures 506A and 506B, second voltage relaxation gate structures 508A and 508B, and reading metal gate structures 510A and 510B are defined along a direction Y that is perpendicular to the direction X (e.g., the continuous active regions 502A and 502B extend along the direction Y). In this example, the gate structures extend across both the continuous active region 502A and the continuous active region 502B. The gate metal can be separated from the continuous active regions 502A and 502B by a thin layer of dielectric material, which in some embodiments can be a high-k dielectric material. Thus, the gate structures described herein can include multiple layers, such as a gate dielectric layer and a gate metal. Any suitable material can be used to form the gate metal of the gate structures described herein, including, for example, PO or any other metal material described herein. As shown, devices formed using a write gate structure 504 (sometimes referred to as the write gate structure 504) and first voltage relaxation gate structures 506A and 506B share source / drain regions. Similarly, each of the first voltage relaxation devices shares a respective source / drain region with an adjacent one of the second voltage relaxation devices. Each of the second voltage devices shares a respective source / drain region with an adjacent one of the read devices. As shown, the source / drain regions of each of the first voltage relaxation devices and the second voltage relaxation devices and each of the read devices may be coupled to a corresponding metal-diffusion layer 516. The metal-diffusion layer 516 may be similar to the metal-diffusion layer 116 of FIG. 1A and may be used to route signals from the source / drain regions of the devices described herein to other circuits. Although not shown here, the write metal gate structure 504, the first voltage relaxation metal gate structures 506A and 506B, the second voltage relaxation metal gate structures 508A and 508B, and the read metal gate structures 510A and 510B and / or any metal-diffusion layer 516 may be coupled to various interconnects to couple the bit cell 520 to other logic circuits. Signals for activating the bit cell 520 (e.g., writing to and / or reading from the bit cell 520) are described in connection with FIG. 5B. The continuous active regions 502A and 502B may include one or more conductive vias 522 defined therethrough, which in this example are shown coupled to the external source / drain nodes of the read devices of each bit cell 520. The conductive vias 522 and any other metal materials described herein (including any gate metal, metal-diffusion layer, or interconnect metal) may be formed of aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof, or may otherwise include aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof. As described herein, the conductive vias may couple one or more of the source / drain nodes of a pair of read transistors to an interconnect (such as a corresponding bit line). As shown, various materials in layout 500A are shown to be separated by dielectric material 518. For example, regions of dielectric material 518 electrically isolate continuous active region 502A from continuous active region 502B, thereby defining two columns of write and read devices, as shown by the orientation. Additionally, the same regions of dielectric material 518 can separate portions of write gate structure 504, first voltage relaxation gate structures 506A and 506B, second voltage relaxation gate structures 508A and 508B, and read metal gate structures 508A and 508B, thereby isolating the gate structures (and the devices formed thereby) on continuous active region 502A from the gate structures formed on continuous active region 502B. In some embodiments, dielectric material 518 can only isolate continuous active regions 502A and 502B from each other, rather than isolating them from write gate structure 504, first voltage relaxation gate structures 506A and 506B, second voltage relaxation gate structures 508A and 508B, and read metal gate structures 508A and 508B, such that the devices formed on each of continuous active regions 502A and 502B can share gate metal. An example circuit diagram showing the electrical connections between each of the write and read devices of bit cell 520 is shown in FIG. 5B. Referring to FIG. 5B, an example circuit diagram 500B of a portion of a memory array corresponding to the layout of FIG. 5A is illustrated according to some embodiments. In the illustrated example of FIG. 5B, one anti-fuse bit cell 520 is shown, and the second anti-fuse bit cell shown in layout 500A is omitted for visual clarity. Although one anti-fuse bit cell 520 is shown, it should be understood that the memory array can have any number of anti-fuse bit cells while still being within the scope of this disclosure. Bit cell 520 can be defined as the portion of the memory array located in a corresponding column and row relative to other bit cells. With this configuration, each of the bit cells can be operatively coupled to access lines in the corresponding column and row, respectively. In FIG. 5B, bit cell 520 is operatively coupled to write character line WLP0, first voltage relaxation character line WLB0, second voltage relaxation character line WLK0, read character line WLR0, and bit line BL0. Each of the access lines (such as WLP0, WLB0, WLK0, WLR0, BL0, etc.) is operatively coupled to a corresponding I / O circuit that transmits a corresponding signal to select bit cell 520 for a write or read operation. These operations can be performed by applying a predetermined pattern of logical selection to each of the access lines. The bit cell 520 includes a write device 524 (sometimes referred to as the write transistor 524), a first pair of voltage relaxation devices 526A and 526B (sometimes referred to as the first voltage relaxation transistors 526A and 526B), a second pair of voltage relaxation devices 528A and 528B (sometimes referred to as the second voltage relaxation transistors 528A and 528B), and a pair of read devices 530A and 530B (sometimes referred to as the read transistors 530A and 530B). As shown, the write transistor 524 is serially coupled to the first pair of serially connected voltage relaxation transistors 526A and 526B such that the source / drain node of the write transistor 524 shares with the respective source / drain nodes of each of the first pair of voltage relaxation transistors 526A and 526B. Another source / drain node of each of the first pair of voltage relaxation transistors 526A and 526B is serially coupled to the second pair of voltage relaxation transistors 528A and 528B such that the respective source / drain nodes of each of the second pair of voltage relaxation transistors 528A and 528B share with the respective ones of the first pair of voltage relaxation transistors 526A and 526B. As shown, another source / drain node of the second pair of voltage relaxation transistors 528A - 528B is serially coupled to the corresponding source / drain of each of the pair of read transistors 530A - 530B. Thus, as shown, the write device 524, the first pair of voltage relaxation devices 526A - 526B, the second pair of voltage relaxation devices 528A - 528B, and the pair of read devices 530A - 530B are serially connected via corresponding source / drain terminals. The external source / drain terminals of the read transistors 530A and 530B are commonly coupled to nodes 532A and 532B, which connect these source / drain terminals to the bit line BL0. Nodes 532A and 532B are also operatively connected to the source / drain terminals of the read devices of adjacent bit cells 520. As shown, the write transistor 524 is gated by a write line WLP0 (e.g., the gate terminal of the write transistor 524 is coupled to WLP0). The first pair of voltage relaxation transistors 526A and 526B are gated by a voltage relaxation word line WLB0 (e.g., the respective gate terminals of the first voltage relaxation transistors 526A and 526B are coupled to the voltage relaxation word line WLB0). The second pair of voltage relaxation transistors 528A and 528B are gated by a voltage relaxation word line WLK0 (e.g., the respective gate terminals of the second voltage relaxation transistors 528A and 528B are coupled to the voltage relaxation word line WLK0). The read transistors 530A and 530B are gated by a read line WLR0 (e.g., the respective gate terminals of the read transistors 530A and 530B are coupled to the read line WLR0). In some embodiments, the write devices, the first pair of voltage relaxation devices, the second pair of voltage relaxation devices, and the read devices of bit cells 320A - 320D may include n-type metal oxide semiconductor field effect transistors (n-type MOSFETs), or sometimes referred to as NMOS transistors. However, it should be understood that each of the write / read devices may include p-type metal oxide semiconductor field effect transistors (p-type MOSFETs) and still be within the scope of this disclosure. It should be understood that the write / read devices described herein may include or otherwise be any type of transistor or switching device suitable for bit cells. To write to bit cell 520, an operation similar to the operation described in connection with FIG. 1B may be performed using a write voltage applied to write line WLP0 while turning on the first pair of voltage relaxation transistors 526A - 526B, the second pair of voltage relaxation transistors 528A - 528B, and read transistors 530A - 530B, and applying a logic low state to bit line BL0. This causes write transistor 524 to break down and change its electrical behavior to act as a resistor. The read process of bit cell 520 may be similar to the read process described in connection with FIG. 1A and may include applying a relatively low level voltage (sometimes referred to as a read voltage) to the gate of write device 524. In some embodiments, the select voltages applied to WLK0 and WLB0 during a write operation (e.g., in write mode) may be between the write voltage applied to WLP0 and the select voltage applied to WLR0. In some embodiments, in write mode, the select voltage applied to WLK0 may be greater than the select voltage applied to WLB0. For example, during a write operation, the select voltage applied to WLK0 may be between about 3V and about 4.5V, while the select voltage applied to WLB0 may be between about 1V and about 3V. However, it should be understood that other voltages may be applied to achieve the desired result. During a read operation, the select voltages applied to WLB0 and WLK0 may be between about 0.5V and 0.9V. In some embodiments, if one or more lines are unselected (e.g., bit cell 520 is not being written or read), the unselect voltage applied to the line may be less than about 0.5V. Referring to FIG. 6, a block diagram of an example layout 600 of a bit cell 620 of a memory array including a dummy gate metal layer located at the edge of a continuous active region is illustrated according to some embodiments. Layout 600 is a top-down layout, in which a plurality of continuous active regions 602A and 602B are defined. The continuous active regions 602A and 602B may be similar to the continuous active regions 102A and 102B of FIG. 1A and may include any suitable semiconductor material, such as silicon or any other type of semiconductor material described herein. Layout 600 is similar to layout 100A described in connection with FIG. 1A, but is near the edges of the continuous active regions 602A and 602B. The continuous active regions 602A and 602B may sometimes be referred to herein as OD regions 602A and 602B. As described in connection with FIGS. 1A, 3A, and 4A, each of the continuous active regions 602A and 602B extends along the X direction as a single continuous region of material, on which a writing device and a reading device (as described in further detail in connection with FIG. 6) are defined. In the example shown in FIG. 6, a bit cell 620 is formed by defining a write gate structure 604 for a first writing device (such as a write transistor), which first writing device may be similar to the first metal gate structure 104 described in connection with FIG. 1A. As shown, additional read gate structures 606A and 606B are formed to define reading devices (such as read transistors) on either side of the writing device formed using the write gate structure 604. The read gate structures 606A and 606B may be similar to the read gate structures 106A and 106B described in connection with FIG. 1A. As shown, the write gate structure 604 and the read gate structures 606A and 606B are defined along a direction Y perpendicular to the direction X (e.g., the continuous active regions 602A and 602B extend along the direction Y). In this example, the gate structures extend across both the continuous active region 602A and the continuous active region 602B. The gate metal may be separated from the continuous active regions 602A and 602B by a thin layer of dielectric material, which may be a high-k dielectric material in some embodiments. Thus, the gate structures described herein may include multiple layers, such as a gate dielectric layer and a gate metal. Any suitable material may be used to form the gate metal of the gate structures described herein, including, for example, PO or any other metal material described herein. As described in connection with FIG. 1A, the devices formed using the write gate structure 604 and the read gate structures 606A and 606B share a source / drain region. As shown, the source / drain regions of the write device and the read devices may be coupled to corresponding metal-diffusion layers 616. The metal-diffusion layer 616 may be similar to the metal-diffusion layer 116 of FIG. 1A and may be used to route signals from the source / drain regions of the devices described herein to other circuits. Although not shown here, the write gate structure 604 and the read gate structures 606A and 606B and / or any metal-diffusion layer 616 may be coupled to various interconnects to couple the bit cell 620 to other logic circuits. Signals for activating the bit cell 620 (e.g., writing to and / or reading from the bit cell 620) are described in connection with FIG. 6. The continuous active regions 602A and 602B may include one or more conductive vias 622 defined therethrough, which in this example are shown coupled to the external source / drain nodes of the read devices of each bit cell 620. The conductive vias 622 and any other metal materials described herein (including any gate metals, metal-diffusion layers, or interconnect metals) may be formed of aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof, or may otherwise include aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof. As described herein, the conductive vias 622 may couple one or more of the source / drain nodes of a pair of read transistors to an interconnect (e.g., a corresponding bit line). As shown, the various materials in the layout 600 are shown separated by a dielectric material 618. For example, regions of the dielectric material 618 electrically isolate the continuous active region 602A from the continuous active region 602B, thereby defining two columns of write and read devices, as shown in this orientation. The dielectric material may be similar to the dielectric material 114 described in connection with FIG. 1A. As described herein, the layouts provided in FIGS. 1A, 3A, 4A, 5A, and 6 enable multiple bit cells to be defined along a single continuous active region (e.g., the continuous active region 602A or 602B). As shown, to address the LOD effects near the edges of the continuous active regions 602A and 602B, additional dummy gate structures 624 may be defined in a pattern similar to the write gate structure 604 and the read gate structures 606A and 606B. The dummy gate structures 624 create a buffer between the functional bit cells 620 and the edges of the continuous active regions 602A and 602B, thereby ensuring the uniformity or electrical characteristics of the external devices in the memory array are not affected by the LOD effects. Although three dummy gate structures 624 are shown here, it should be understood that any number of dummy gate structures 624 can be defined adjacent to the edges of the continuous active regions 602A and 602B. In one example, the number of dummy gate structures 624 can range from one to ten dummy gate structures 624. As shown, the dummy gate structures 624 are defined over the continuous active regions 602A and 602B. The number of dummy gate structures 624 can be selected to optimize both the electrical characteristics of the device and the total device area. Any suitable gate metal described herein can be used to define the dummy gate structures 624 or a non-conductive material (such as a dielectric) can be used to define the dummy gate structures 624. Additionally, although only one edge (such as the leftmost edge) of the continuous active regions 602A and 602B is shown here, it should be understood that similar dummy gate structures 624 can be defined along the second edge (such as the rightmost edge) of the continuous active regions 602A and 602B. Referring to FIG. 7, a flowchart of an example method 700 for manufacturing the bit cells of FIGS. 1A-6 is illustrated in accordance with some embodiments. For example, method 700 includes operations for fabricating transistors of the antifuse cells over a continuous active region. It should be noted that method 700 is merely an example and is not intended to limit this disclosure. Thus, it should be understood that additional operations can be provided before, during, and after the method 700 of FIG. 7, and some other operations may only be briefly described herein. Method 700 begins with operation 702, in which a continuous active region (such as continuous active region 102A and / or continuous active region 102B of FIG. 1A, etc.) is formed. The continuous active region is formed to extend along a first direction (such as the X direction shown in FIG. 1A), and write devices, read devices, and in some embodiments, voltage relaxation devices will be defined over the continuous active region. In some embodiments, the continuous active region can be defined on a substrate material or can be defined as part of the substrate material. The substrate can include a semiconductor material substrate, such as silicon. In some embodiments, the substrate can include other elemental semiconductor materials, such as (for example) germanium. The substrate can include compound semiconductors, such as silicon carbide, gallium arsenide, indium arsenide, and indium phosphide. The substrate can include alloy semiconductors, such as silicon germanium, silicon carbide germanium, gallium arsenide phosphide, and gallium indium phosphide. In some embodiments, the substrate includes an epitaxial layer. For example, the substrate can have an epitaxial layer covering a bulk semiconductor. Additionally, the substrate can include a SOI substrate. For example, the substrate can include a buried oxide (BOX) layer formed by a process such as separation by implanted oxygen (SIMOX) or other suitable techniques such as wafer bonding and grinding. In some embodiments, a continuous active region is defined as part of a substrate material or defined on the substrate material and may include performing shallow trench isolation (STI) to isolate different continuous active regions from each other (e.g., defining continuous active regions 102A and 102B separated from each other, etc.). The STI process may include etching trenches of a predetermined depth in the substrate material and then filling the trenches with a dielectric material (e.g., dielectric material 114) to electrically isolate the continuous active regions from each other. In some embodiments, the STI process may be used to define a plurality of parallel continuous active regions extending along a first direction (e.g., the X direction) along a second direction (e.g., the Z direction of FIG. 1A). Once the dielectric material has been formed, excess dielectric material may be removed, and the top surface of the device may be planarized, for example, using a chemical mechanical polishing (CMP) process. Next, source / drain regions may be formed to define source / drain terminals of write devices (e.g., write device 122 of FIG. 1B), read devices (e.g., read devices 124A and 124B of FIG. 1B), and in some embodiments, voltage relaxation devices (e.g., one pair of voltage relaxation devices 326A and 326B of FIG. 3B, multiple pairs of voltage relaxation devices 426A to 426D of FIG. 4B, or multiple pairs of voltage relaxation devices 526A to 526B and 528A to 528B of FIG. 5B, etc.). In some embodiments, a "post-gate" or "replace-gate" method may be used to form the source / drain regions. In such embodiments, a dummy gate material (e.g., polysilicon, etc.) may be initially formed and patterned to correspond to the geometry of the gate structure shown in FIG. 1A, FIG. 3A, FIG. 4A, FIG. 5A, or FIG. 6 according to various embodiments. These dummy gate structures may be used as a placeholder during the formation of the source / drain regions. The source / drain regions may be patterned and defined within the continuous active region. For example, N-type and p-type FETs may be formed by implanting different types of dopants into selected regions of the continuous active region of the device to form the necessary junction surfaces. An N-type device may be formed by implanting arsenic (As) or phosphorus (P), and a p-type device may be formed by implanting boron (B). Next, in steps 704 and 706, the dummy gate structures may be removed and replaced by forming an active gate structure (e.g., the gate structure of a write device, a read device, and in some embodiments, a voltage relaxation device, etc.). In another embodiment (e.g., the "first" method), method 700 may proceed to steps 704 and 706 to form a metal gate structure before forming the source / drain structure. Method 700 proceeds to operation 704, in which a first gate structure (e.g., gate structure 104) of a write transistor (e.g., write transistor 122) is formed over a continuous active region. As described herein, the gate structure may include a high-k metal gate structure and may include at least a gate dielectric layer (e.g., a high-k dielectric layer) and a gate metal layer (e.g., a work function metal layer). Forming a gate structure for a write transistor may include performing any suitable material formation techniques, including atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma-enhanced CVD (PECVD), epitaxial growth or deposition techniques, or combinations thereof. The gate structure may be formed to extend along a second direction perpendicular to the first direction. In some embodiments, each gate structure formed for a write device may extend across multiple continuous active regions (e.g., across both continuous active regions 102A and 102B as shown in FIG. 1A), thereby defining multiple write transistors for multiple bit cells sharing a single gate structure. Any suitable patterning technique may be used to define the gate structure of the write device. Method 700 proceeds to operation 706, in which a second gate structure (e.g., read gate structure 106A) and a third gate structure (e.g., read gate structure 106B) are formed over the continuous active region. As shown in FIG. 1A, the second gate structure and the third gate structure may be formed such that the first gate structure is formed between the second gate structure and the third gate structure. In some embodiments, the same material deposition process may be used to simultaneously define the first gate structure, the second gate structure, and the third gate structure. In some embodiments, one or more voltage relaxation gate structures (e.g., voltage relaxation gate structures 306A and 306B, voltage relaxation gate structures 406A-406D, first voltage relaxation gate structures 506A-506B, and second voltage relaxation gate structures 508A-508B, etc.) may be selectively provided. Forming a gate structure for a write transistor may include performing any suitable material formation techniques, including ALD, CVD, PVD, PECVD, epitaxial growth or deposition techniques, or combinations thereof. The gate structure may be formed to extend along a second direction perpendicular to the first direction. In some embodiments, each gate structure formed for a read transistor and / or a voltage relaxation device may extend across multiple continuous active regions, thereby defining multiple read transistors and / or voltage relaxation devices for multiple bit cells sharing a single gate structure. Any suitable patterning technique may be used to define the gate structure of the read device and / or the voltage relaxation device. In an embodiment of forming a voltage relaxation device, the gate structure of the voltage relaxation gate structure may be formed such that the voltage relaxation device is defined between a write device and a read device, as shown in FIGS. 3A, 4A, and 5A. In some embodiments, the write device, the voltage relaxation device, and the read device may be defined in a symmetric configuration. In some embodiments, rather than defining two of each of the write devices, the pairs of voltage relaxation devices, and the pairs of read devices as described in connection with FIGS. 4A and 4B, any positive integer number of write devices, pairs of voltage relaxation devices, and pairs of read devices may be formed. Similarly, any integer multiple of the devices described in connection with FIGS. 5A and 5B may be formed in series with each other to achieve a useful result. In some embodiments, in addition to forming a high-k metal gate structure for the devices described herein, a dummy gate structure may be formed near the ends of the continuous active regions, as described in connection with FIG. 6. The dummy gate structure may include a high-k / metal material similar to the materials described herein, or other materials such as polysilicon or dielectric materials. The dummy gate structure may define non-functional regions of the continuous active regions such that the functional bit cells formed according to the techniques described herein are not affected by the LOD effect. The dummy gate structure may be formed in the same pattern as the gate structures of the write devices, read devices, and voltage relaxation devices described herein, as shown in FIG. 6. The dummy gate structure may be formed simultaneously with the gate structures of the write devices, read devices, and voltage relaxation devices, or may be formed in a separate step using suitable material deposition techniques. In some embodiments, the number of dummy gate structures may be from one to ten dummy gate structures. Method 700 proceeds to operation 710, in which one or more bit lines (e.g., BL0, BL1, one or more of metal layers 218, 220, 222, 232, or 236 of FIGS. 2A-2B) are formed. The bit lines may be coupled to a first source / drain structure of a first one of a pair of read transistors and a second source / drain structure of a second one of the pair of read transistors. In some embodiments, one or more of a front-side metallization process or a back-side metallization process may be used to form the bit lines. For example, various interconnect structures (including conductive vias, metal-diffusion layers, or other types of metal layers) may be formed on the continuous active regions and / or gate structures formed in previous steps of method 700 to form the bit lines and other structures, thereby coupling the bit cells described herein to other circuits. Any suitable number of interconnect structures can be formed to achieve a useful result and couple the various components of the bit cell to each other. For example, according to the configurations described herein, conductive vias can be formed to connect the gate terminals of one or more write transistors to a write word line, and additional conductive vias can be formed to connect the gate terminals of the read transistors to a common read word line and the gate terminals of the voltage relaxation devices to corresponding voltage relaxation lines. As described herein, metal-diffusion layers and corresponding vias can be formed to connect the source terminals of the read transistors to one or more bit lines. The bit lines and other layers corresponding to the write lines, read select lines, or voltage relaxation select lines can be formed of a metal material layer. The metal material can be selected from the group consisting of: aluminum, tungsten, tungsten nitride, copper, cobalt, silver, gold, chromium, ruthenium, platinum, titanium, titanium nitride, tantalum, tantalum nitride, nickel, hafnium, and combinations thereof. Other metal materials are also within the scope of this disclosure. The interconnect structures can be formed by covering a workpiece with the above-listed metal materials by, for example, CVD, PVD, electroless plating, electroplating, or combinations thereof. In one aspect of this disclosure, a memory array is disclosed. The memory array includes: a continuous active region extending in one direction; a first memory cell including a pair of a first write device and a first read device defined on the continuous active region; a first write word line coupled to the gate of the first write device; a first read word line coupled to the gates of the pair of first read devices; and a bit line. In the memory array, the first one of the pair of first read devices is coupled between the first source / drain node of the first write device and the bit line. In another aspect of this disclosure, a circuit is disclosed. The circuit includes: a first write transistor defined on a continuous active region; and a pair of read transistors defined on the continuous active region along one direction, the first write transistor being positioned between the pair of read transistors, wherein the respective first source / drain nodes of the pair of read transistors are each coupled to a bit line. In yet another aspect of this disclosure, a method for manufacturing a memory device is disclosed. The method includes: forming a continuous active region extending in a first direction; forming a first gate structure of a write transistor on the continuous active region; forming second and third gate structures of a pair of read transistors on the continuous active region, the first gate structure being formed between the second and third gate structures; and forming a bit line coupled to a first source / drain structure of the first one of the pair of read transistors and a second source / drain structure of the second one of the pair of read transistors. As used herein, the terms "about" and "approximately" generally mean plus or minus 10% of a specified value. For example, about 0.5 will include 0.45 and 0.55, about 10 will include 9 to 11, and about 1000 will include 900 to 1100. The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the various aspects of the present disclosure. Those skilled in the art should appreciate that they can readily use the present disclosure as a basis for designing or modifying other processes and structures for achieving the same purposes and / or achieving the same advantages as the embodiments introduced herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the present disclosure. 100A, 300A, 400A, 500A, 600: Layout 100B, 300B, 400B, 500B: Circuit Diagram 102A, 102B, 202, 302A, 302B, 402A, 402B, 502A, 502B, 602A, 602B: Active Region 104, 304, 504, 604: First Metal Gate Structure 106, 310: Second Metal Gate Structure 106A, 106B, 308A, 308B: Read Metal Gate Structure 206, 210A, 210B, 228: Gate Structure 108A, 108B, 112A, 112B, 314A, 314B: Second Read Metal Gate Structure 110: Third Metal Gate Structure 114, 318, 418, 518, 618: Dielectric Material 116, 316, 416, 516, 616: Metal-Diffusion Layer 118, 216, 219, 222, 234, 322, 422, 522, 622: Conductive Through-Hole 120, 240, 320, 420, 520, 620: Bit Cell 120A, 120B, 120C, 120D, 120E, 120F, 320A, 320B, 320C, 320D: Antifuse Bit Cell 122, 324, 424, 524: Programming Transistor 124A, 124B, 328A, 328B, 428A, 428B, 428C, 428D, 530A, 530B: Read Transistor 126A, 126B, 330A, 330B, 430A, 430B, 532A, 532B: Node 200A, 200B: Layout Diagram 204: Programming Device Gate Structure 208A, 208B: Read Device Gate Structure 214: Metal-Diffusion Region 218, 220, 224: Front-Side Metal Layer 230: Back-Side Through-Hole 231: Source / Drain Region 232, 236: Back-Side Metal Layer 306A, 306B, 406A, 406B, 406C, 406D: Voltage Relaxation Gate Structure 312A, 312B, 508A, 508B: Second Voltage Relaxation Gate Structure 326A, 326B, 426A, 426B, 426C, 426D, 526A, 526B: Voltage Relaxation Transistor 404A, 404B, 510A, 510B: Metal Gate Structure 408A, 408B, 408C, 408D, 606A, 606B: Read Gate Structure 424A: First Programming Transistor 424B: Second Programming Transistor 506A, 506B: First Voltage Relaxation Gate Structure 528A, 528B: Second Voltage Relaxation Transistor 624:Dummy Gate Structure 700: Method 702, 704, 706, 710: OperationBL0, BL1, WLB0, WLB1, WLK0, WLP0, WLP1, WLP2, WLR0, WLR1, WLR2: Access lines Various aspects of the present disclosure may be best understood when reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, in accordance with standard conventions in the industry, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased. FIG. 1A illustrates a block diagram of an example layout of bit cells of a memory array according to some embodiments. FIG. 1B illustrates an example circuit diagram of a portion of the memory array corresponding to the layout of FIG. 1A according to some embodiments. FIG. 2A illustrates a cross-sectional layout diagram of an example bit cell having a front-side metal layer, similar to the bit cells shown in FIGS. 1A and 1B according to some embodiments. FIG. 2B illustrates a cross-sectional layout diagram of an example bit cell having front-side and back-side metal layers, similar to the bit cells shown in FIGS. 1A and 1B according to some embodiments. FIG. 3A illustrates a block diagram of an example layout of bit cells of a memory array including a voltage relaxation device according to some embodiments. FIG. 3B illustrates an example circuit diagram of a portion of the memory array corresponding to the layout of FIG. 3A according to some embodiments. FIG. 4A illustrates a block diagram of an example layout of bit cells of a memory array including multiple write devices according to some embodiments. FIG. 4B illustrates an example circuit diagram of a portion of the memory array corresponding to the layout of FIG. 4A according to some embodiments. FIG. 5A illustrates a block diagram of an example layout of bit cells of multiple pairs of memory arrays including voltage relaxation devices according to some embodiments. FIG. 5B illustrates an example circuit diagram of a portion of the memory array corresponding to the layout of FIG. 5A according to some embodiments. FIG. 6 illustrates a block diagram of an example layout of bit cells of a memory array including a dummy gate metal layer located at the edge of a continuous active region according to some embodiments. FIG. 7 illustrates a flowchart of an example method for manufacturing the bit cells of FIGS. 1A to 6 according to some embodiments. Domestic deposit information (please note in the order of deposit institution, date, number) None Foreign deposit information (please note in the order of deposit country, institution, date, number) None 100A: Layout 102A, 102B: Active regions 104: First metal gate structure 106: Second metal gate structure 106A, 106B: Read metal gate structures 108A, 108B, 112A, 112B: Second read metal gate structures 110: Third metal gate structure 114: Dielectric material 116: Metal-diffusion layer 118: Conductive via 120: Bit cell

Claims

1. A memory array, comprising: A continuous active region, extending in one direction; A first bit unit includes a first writing device and a pair of multiple first reading devices defined on the continuous active area; A first character line is coupled to a gate of the first writing device; A first read character line is coupled to the multiple gates of the pair of multiple first read devices; And a bit line, wherein a first of the pair of multiple first reading devices is coupled between a first source / drain node of the first writing device and the bit line, wherein a first source / drain node of the first of the pair of multiple first reading devices and a first source / drain node of a second of the pair of multiple first reading devices are jointly coupled to a single bit line.

2. The memory array as described in claim 1, wherein the first writing device is defined between the pair of a plurality of first reading devices.

3. The memory array as described in claim 1, further comprising an isolation structure surrounding the continuous active region.

4. The memory array as claimed in claim 1, further comprising a second bit cell defined on the continuous active region and arranged along the direction, wherein the second bit cell includes a second writing device and a pair of a plurality of second reading devices along the direction.

5. The memory array as claimed in claim 1, wherein the second of the pair of plurality of first read devices is coupled between a second source / drain node of the first write device and the bit line.

6. The memory array as described in claim 1, further comprising: A first pair of multiple voltage mitigation devices, wherein the first writing device is located between the first pair of multiple voltage mitigation devices, and the voltage mitigation devices are located between the pair of multiple first reading devices.

7. A circuit comprising: A first programming transistor is defined on a continuous active region; and a pair of read transistors are defined on the continuous active region along a direction, the first programming transistor being positioned between and coupled to the pair of read transistors, wherein a first source / drain node of a first of the pair of read transistors and a second source / drain node of a second of the pair of read transistors are co-coupled to a single bit line.

8. The circuit as claimed in claim 7, wherein a second source / drain node of the first of the plurality of read transistors in the pair is coupled to a second source / drain node of the second of the plurality of read transistors in the pair to a plurality of corresponding source / drain nodes of the first write transistor.

9. A method for manufacturing a memory device, comprising the steps of: forming a continuous active region extending along a first direction; forming a first gate structure of a programming transistor on the continuous active region; forming a second gate structure and a third gate structure of a pair of read transistors on the continuous active region, the first gate structure being formed between the second gate structure and the third gate structure; and forming a single bit line commonly coupled to a first source / drain structure of a first of the pair of read transistors and a second source / drain structure of a second of the pair of read transistors.

10. The method of claim 9, wherein the step of forming the bit line includes the following steps: forming a conductive via in the continuous active region; and forming a metal layer for coupling the bit line to the conductive via.

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