semiconductor element

Abstract

A semiconductor device includes a sense amplifier, a first magnetic tunneling junction (MTJ) connected to the sense amplifier along a first distance, a second MTJ connected to the sense amplifier along a second distance, and a third MTJ connected to the sense amplifier along a third distance, wherein the first distance is less than the second distance, the second distance is less than the third distance, a critical dimension of the first MTJ is less than a critical dimension of the second MTJ, and the critical dimension of the second MTJ is less than a critical dimension of the third MTJ.

Description

Technical Field

[0001] This invention relates to a semiconductor device, and more particularly to a magnetoresistive random access memory (MRAM) device. Background Technology

[0002] Magnetoresistance (MR) is the effect of a material's resistance changing with the application of a magnetic field. Its physical quantity is defined as the rate of change of resistance, calculated by dividing the resistance difference (with and without a magnetic field) by the original resistance. Currently, the magnetoresistance effect has been successfully applied in hard drive manufacturing and has significant commercial value. Furthermore, utilizing the characteristic that giant magnetoresistance materials have different resistance values ​​under different magnetization states, magnetic random access memory (MRAM) can also be fabricated, which has the advantage of retaining stored data even when no power is applied.

[0003] The aforementioned magnetoresistive effect is also applied in the field of magnetic field sensing, such as in the electronic compass components of mobile phones that integrate with the Global Positioning System (GPS) to provide users with information such as their location. Currently, various magnetic field sensing technologies are available on the market, such as anisotropic magnetoresistive (AMR) sensing elements, giant magnetoresistive (GMR) sensing elements, and magnetic tunneling junction (MTJ) sensing elements. However, these existing technologies typically have drawbacks, including larger chip area, higher manufacturing costs, higher power consumption, insufficient sensitivity, and susceptibility to temperature changes, necessitating further improvements. Summary of the Invention

[0004] An embodiment of the present invention discloses a semiconductor device, which mainly includes a sensing amplifier, a first magnetic tunneling junction (MTJ) connected to the sensing amplifier along a first distance, a second MTJ connected to the sensing amplifier along a second distance, and a third MTJ connected to the sensing amplifier along a third distance, wherein the first distance is smaller than the second distance, the second distance is smaller than the third distance, the critical size of the first MTJ is smaller than the critical size of the second MTJ, and the critical size of the second MTJ is smaller than the critical size of the third MTJ. Attached Figure Description

[0005] Figure 1This is a block diagram of an MRAM element according to an embodiment of the present invention;

[0006] Figure 2 This is a block diagram of an MRAM element according to an embodiment of the present invention.

[0007] Explanation of main component symbols

[0008] 12: Sensing Amplifier

[0009] 14: First MTJ

[0010] 16: Second MTJ

[0011] 18: Third MTJ Detailed Implementation

[0012] Certain terms are used in the specification and subsequent claims to refer to specific elements. It will be understood by those skilled in the art that manufacturers may use different names to refer to the same element. This specification and claims do not distinguish elements by differences in name, but rather by differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." Furthermore, the terms "connection" or "coupling" herein include any direct and indirect electrical connection means. Therefore, if a first device is described as connected to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

[0013] Please refer to Figure 1 , Figure 1 This is a block diagram of a semiconductor element, or more specifically, an MRAM element, according to an embodiment of the present invention. Figure 1 As shown, an MRAM element mainly includes a sense amplifier 12 and three MTJs connected to the sense amplifier along different distances or paths. Specifically, a first MTJ 14 is connected to the sense amplifier 12 along a first distance, a second MTJ 16 is connected to the sense amplifier 12 along a second distance, and a third MTJ 18 is connected to the sense amplifier 12 along a third distance. Generally, the main function of the sense amplifier is to convert the information stored in the storage capacitor into a voltage corresponding to logic 1 or 0 and present it on the bit line. Simultaneously, after completing a read operation, the charge in the storage capacitor is restored to its state before the read operation via the bit line.

[0014] In this embodiment, each of the first MTJ 14, the second MTJ 16, and the third MTJ 18 may, according to manufacturing process requirements, include, for example, a lower electrode (not shown), a pinned layer, a barrier layer, a free layer, and an upper electrode (not shown). In this embodiment, the lower and upper electrodes preferably contain conductive materials, such as, but not limited to, tantalum (Ta), tantalum nitride (TaN), platinum (Pt), copper (Cu), gold (Au), and aluminum (Al). The pinned layer may contain ferromagnetic materials such as, but not limited to, cobalt-iron-boron (CoFeB), cobalt-iron (CoFe), iron (Fe), and cobalt (Co). Furthermore, the pinned layer may also be composed of antiferromagnetic (AFM) materials, such as iron-manganese (FeMn), platinum-manganese (PtMn), iridium-manganese (IrMn), and nickel oxide (NiO), to fix or restrict the magnetic moment direction of adjacent layers. The barrier layer can be made of an insulating material containing oxides, such as aluminum oxide (AlOx) or magnesium oxide (MgO), but is not limited to these. The free layer can be made of ferromagnetic materials, such as iron, cobalt, nickel, or their alloys such as cobalt-iron-boron (CoFeB), but is not limited to these. The magnetization direction of the free layer can be "freely" changed by an external magnetic field.

[0015] It is worth noting that in this embodiment, the distance between the MTJ and the sensing amplifier is preferably inversely proportional to the critical size of the MTJ itself. For example, the distance between the first MTJ 14 and the sensing amplifier 12 (such as the first distance) is preferably smaller than the distance between the second MTJ 16 and the sensing amplifier 12 (such as the second distance), the distance between the second MTJ 16 and the sensing amplifier 12 is smaller than the distance between the third MTJ 18 and the sensing amplifier 12 (such as the third distance), and the critical size of the first MTJ 14 is preferably smaller than the critical size of the second MTJ 16, and the critical size of the second MTJ 16 is smaller than the critical size of the third MTJ 18.

[0016] In this embodiment, the distance between the so-called sensing amplifier 12 and MTJ may include the total length of any physical metal interconnect or metal winding connecting the sensing amplifier 12 and MTJ, and the critical dimension of MTJ may include the length, width, or the sum of both of the entire MTJ at the upward viewing angle, wherein the so-called entire MTJ may include the length, width, or the sum of both of the upper electrode, free layer, barrier layer, fixed layer, or lower electrode.

[0017] by Figure 1Considering the distances between the sensing amplifier 12 and the three MTJs, the distance between the first MTJ 14 and the sensing amplifier 12 (as the first distance) preferably includes the sum of distances D1 and D2; the distance between the second MTJ 16 and the sensing amplifier 12 (as the second distance) preferably includes the sum of distances D1, D3, and D4; and the distance between the third MTJ 18 and the sensing amplifier 12 (as the third distance) includes the sum of distances D1, D3, D5, and D6.

[0018] In addition Figure 1 Taking a rectangular MTJ as an example from a top-view perspective, the critical dimensions of each MTJ may include the length or width of the upper electrode, the length or width of the free layer, the length or width of the barrier layer, the length or width of the fixed layer, or the length or width of the lower electrode. In detail, each MTJ may include a length extending along a first direction, such as the X direction, and a width extending along a second direction perpendicular to the first direction, such as the Y direction. For example, the first MTJ 14 may include a length L1 and a width W1, the second MTJ 16 may include a length L2 and a width W2, and the third MTJ 18 may include a length L3 and a width W3. Preferably, the length L1 of the first MTJ 14 is less than the length L2 of the second MTJ 16, the width W1 of the first MTJ 14 is preferably less than the width W2 of the second MTJ 16, the length L2 of the second MTJ 16 is less than the length L3 of the third MTJ 18, and the width W2 of the second MTJ 16 is less than the width W3 of the third MTJ 18.

[0019] It should also be noted that although this embodiment only sets three MTJs to connect to the sensing amplifier 12, it is not limited to this. According to other embodiments of the present invention, the number and size of MTJs can be adjusted according to the manufacturing process or product requirements. For example, four, five or even six or more MTJs can be set to connect to the sensing amplifier 12 at the same time, and the critical size of the MTJ closer to the sensing amplifier 12 is preferably smaller than the critical size of the MTJ farther away from the sensing amplifier 12.

[0020] Please refer to again Figure 2 , Figure 2 A block diagram of an MRAM element according to another embodiment of the present invention is also disclosed. (See diagram below.) Figure 2 As shown, compared to the rectangular shape of the MTJ in the aforementioned embodiments when viewed from above, another embodiment of the present invention allows for adjusting the pattern of the photomask during MTJ formation or performing optical proximity correction (OPC) and other correction steps to make the formed MTJ appear approximately circular, such as a perfect circle, ellipse, or flat ellipse, when viewed from above. Figure 2Taking an elliptical MTJ as an example, each MTJ may include a major axis extending along a first direction such as the X direction and a minor axis extending along a second direction perpendicular to the first direction such as the Y direction. For example, the first MTJ 14 may include a major axis X1 and a minor axis Y1, the second MTJ 16 may include a major axis X2 and a minor axis Y2, and the third MTJ 18 may include a major axis X3 and a minor axis Y3.

[0021] As in the aforementioned embodiments, the distance between the MTJ and the sensing amplifier is preferably inversely proportional to the critical size of the MTJ itself. For example, the distance between the first MTJ 14 and the sensing amplifier 12 is preferably smaller than the distance between the second MTJ 16 and the sensing amplifier 12, and the distance between the second MTJ 16 and the sensing amplifier 12 is smaller than the distance between the third MTJ 18 and the sensing amplifier 12. At the same time, the critical size of the first MTJ 14 is preferably smaller than the critical size of the second MTJ 16, and the critical size of the second MTJ 16 is smaller than the critical size of the third MTJ 18. The critical size of the MTJ may be included in the major axis or minor axis of each MTJ under the upward viewing angle.

[0022] by Figure 2 Considering the distances between the sensing amplifier 12 and the three MTJs, the distance between the first MTJ 14 and the sensing amplifier 12 (as the first distance) preferably includes the sum of distances D1 and D2; the distance between the second MTJ 16 and the sensing amplifier 12 (as the second distance) preferably includes the sum of distances D1, D3, and D4; and the distance between the third MTJ 18 and the sensing amplifier 12 (as the third distance) includes the sum of distances D1, D3, D5, and D6.

[0023] In addition Figure 2 Taking an elliptical MTJ as an example, the critical dimensions of each MTJ can include the major or minor axis of the upper electrode, the major or minor axis of the free layer, the major or minor axis of the barrier layer, the major or minor axis of the fixed layer, or the major or minor axis of the lower electrode. Preferably, the major axis X1 of the first MTJ 14 is smaller than the major axis X2 of the second MTJ 16, the minor axis Y1 of the first MTJ 14 is smaller than the minor axis Y2 of the second MTJ 16, the major axis X2 of the second MTJ 16 is smaller than the major axis X3 of the third MTJ 18, and the minor axis Y2 of the second MTJ 16 is smaller than the minor axis Y2 of the third MTJ 18. Y3 .

[0024] Generally speaking, the critical size of an MTJ (Metal Transfer Junction) will affect its magnetoresistance or resistance. For example, a smaller critical size will increase the resistance, while a larger critical size will decrease the resistance. Simultaneously, the parasitic resistance of the sensing amplifier is positively correlated with the parasitic resistance of the surrounding metal interconnects or wires. For instance, the closer to the sensing amplifier or the innermost metal interconnects, the lower the parasitic resistance; conversely, the farther away from the sensing amplifier or the outermost layer, the higher the parasitic resistance.

[0025] To compensate for the high and low parasitic resistance caused by the metal interconnects around the sensing amplifier, this invention preferably adjusts the critical size of each MTJ according to the distance between the sensing amplifier and the surrounding MTJs, thereby enabling a more stable read voltage when the sensing amplifier reads. For example, this invention preferably places MTJs with smaller critical sizes closer to the sensing amplifier and MTJs with larger critical sizes farther away from the sensing amplifier. The distance between the sensing amplifier and the MTJ can include the length of any metal interconnect that physically connects the sensing amplifier and the MTJ, and the critical size of the MTJ can include any distance parameter such as length, width, major axis, minor axis, or even circumference, diameter, or radius that can be compared with adjacent MTJs based on the shape of the MTJ from a top-view perspective.

[0026] Based on specific experimental data, a difference of one nanometer in the critical size between MTJs can lead to an increase of 200 ohms in parasitic resistance. In order to compensate for the high and low parasitic resistance of the aforementioned sensing amplifier, the present invention preferably controls the difference between the critical size of the farthest MTJ (such as the third MTJ) and the critical size of the closest MTJ (such as the first MTJ) to the sensing amplifier to be between 3 nanometers and 6 nanometers, or preferably about 4 nanometers, so that the sensing amplifier can achieve the most stable reading voltage when reading.

[0027] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. A semiconductor device, characterized in that, Include: Sensing amplifier; A first magnetic tunneling junction (MTJ) is connected to the sensing amplifier along a first distance; as well as A second magnetic tunneling junction is connected to the sensing amplifier along a second distance, wherein the first distance is smaller than the second distance and the critical size of the first magnetic tunneling junction is smaller than the critical size of the second magnetic tunneling junction.

2. The semiconductor element of claim 1, further comprising a third magnetic tunnel junction connected to the sensing amplifier along a third distance.

3. The semiconductor element of claim 2, wherein the second distance is less than the third distance.

4. The semiconductor device of claim 2, wherein the critical size of the second magnetic tunnel junction is smaller than the critical size of the third magnetic tunnel junction.

5. The semiconductor device of claim 4, wherein the difference between the critical size of the first magnetic tunneling junction and the critical size of the third magnetic tunneling junction is between 3 nanometers and 6 nanometers.

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