Patent Application
20220180911
The present invention relates generally to the field of magnetic tunnel junctions (MTJ), and more particularly to applying a magnetic field to the MTJ to control the stability of the free layer.
A Magnetic Tunnel Junction (MTJ) is usually comprised of a free layer, a first reference layer, and a second reference layer. The balancing between the first reference layer (RL1) and the second reference layer (RL2) sometimes is very challenging and is being carried out by controlling the thickness of the layers down to a few angstroms.
Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
An apparatus comprising a magnetic tunnel junction (MTJ), a diffusion barrier, wherein the MTJ is located on the diffusion barrier and a bottom contact that includes a magnetic field generating component, wherein the diffusion barrier is located on top of the bottom contact, wherein the magnetic field generated by the magnetic field generating component affects the stability of the MTJ.
In accordance with an aspect of the present invention, wherein the magnetic field generating component is a magnetic liner.
In accordance with an aspect of the present invention, wherein the magnetic liner is located on sides and bottom of the bottom contact.
In accordance with an aspect of the present invention, wherein magnetic liner has a positive polarity and a negative polarity, wherein the positive polarity can be located on the outside surface of the magnetic liner or on the inside surface of the magnetic liner, wherein the negative polarity is located on a surface magnetic liner opposite of the positive polarity.
In accordance with an aspect of the present invention, wherein the magnetic liner generates two magnetic fields centered at each end of the magnetic liner in contact with the diffusion barrier.
In accordance with an aspect of the present invention, wherein each end of the magnetic liner needs to less than 100 nm away from the MTJ.
In accordance with an aspect of the present invention, wherein a material of the magnetic liner can be selected from a group that includes Co, Ni, or ferromagnetic materials.
In accordance with an aspect of the present invention, wherein the MTJ includes a free layer, wherein the generated magnetic field affects the stability of the free layer in the MTJ.
In accordance with an aspect of the present invention, wherein the magnetic liner has a polarity such that the generated magnetic field extends from a first end of the liner on one side of the bottom contact to a second end of the liner located on another side of the bottom contact.
In accordance with an aspect of the present invention, wherein each end of the magnetic liner needs to in the range of 20-50× the thickness of the magnetic liner away from the MTJ.
In accordance with an aspect of the present invention, wherein a material of the magnetic liner can be selected from a group that includes Co, Ni, or ferromagnetic materials.
In accordance with an aspect of the present invention, wherein the MTJ includes a free layer, wherein the generated magnetic field affects the stability of the free layer in the MTJ.
In accordance with an aspect of the present invention, wherein the bottom contact is comprised of a magnet material or the bottom contact is comprised of metal doped with a magnetic material.
In accordance with an aspect of the present invention, wherein the bottom contact as a first polarity at side in contact with the diffusion barrier and the bottom contact has a second polarity on the side farthest from the diffusion barrier, wherein the first polarity is the opposite polarity of the second polarity.
In accordance with an aspect of the present invention, wherein the bottom contact generates a first magnetic field that extends from the bottom of a first side of the bottom contact to top of the first side of the bottom contact and the bottom contact generates a second magnetic field that extends from the bottom of a second side of the bottom contact to top of the second side of the bottom contact.
In accordance with an aspect of the present invention, wherein the MTJ includes a free layer, wherein the generated the first magnetic field and the second magnetic affects the stability of the free layer in the MTJ.
In accordance with an aspect of the present invention, wherein the bottom contact as a positive polarity at a first horizontal end of bottom contact and the bottom contact has a negative polarity on a second horizontal end bottom contact, wherein the first horizontal end and second horizontal end are at opposite ends of the bottom contact.
In accordance with an aspect of the present invention, wherein the bottom contact generates a first magnetic field that extends from the top of a first horizontal end of the bottom contact to top of the second horizontal end of the bottom contact and the bottom contact generates a second magnetic field that extends from the bottom of first horizontal end of the bottom contact to the bottom of the second horizontal end of the bottom contact.
In accordance with an aspect of the present invention, wherein the MTJ includes a free layer, wherein the generated the first magnetic field affects the stability of the free layer in the MTJ.
In accordance with an aspect of the present invention, wherein the magnetic material of bottom contact or the magnet doping material can be selected from a group that includes Co, Ni, or ferromagnetic materials.
The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
The terms and the words used in the following description and the claims are not limited to the bibliographical meanings but are merely used to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces unless the context clearly dictates otherwise.
Detailed embodiments of the claimed structures and the methods are disclosed herein: however, it can be understood that the disclosed embodiments are merely illustrative of the claimed structures and methods that may be embodied in various forms. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of this invention to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present embodiments.
References in the specification to “one embodiment,” “an embodiment,” an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one of ordinary skill in the art o affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
For purpose of the description hereinafter, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and derivatives thereof shall relate to the disclosed structures and methods, as orientated in the drawing figures. The terms “overlying,” “atop,” “on top,” “positioned on,” or “positioned atop” mean that a first element, such as a first structure, is present on a second element, such as a second structure, wherein intervening elements, such as an interface structure may be present between the first element and the second element. The term “direct contact” means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediary conducting, insulating, or semiconductor layer at the interface of the two elements.
In the interest of not obscuring the presentation of embodiments of the present invention, in the following detailed description, some processing steps or operations that are known in the art may have been combined together for presentation and for illustrative purposes and in some instance may have not been described in detail. In other instances, some processing steps or operations that are known in the art may not be described at all. It should be understood that the following description is rather focused on the distinctive features or elements of various embodiments of the present invention.
Various embodiments of the present invention are described herein with reference to the related drawings. Alternative embodiments can be devised without departing from the scope of this invention. It is noted that various connections and positional relationships (e.g., over, below, adjacent, etc.) are set forth between elements in the following description and in the drawings. These connections and/or positional relationships, unless specified otherwise, can be direct or indirect, and the present invention is not intended to be limiting in this respect. Accordingly, a coupling of entities can refer to either a direct or indirect coupling, and a positional relationship between entities can be direct or indirect positional relationship. As an example of indirect positional relationship, references in the present description to forming layer “A” over layer “B” includes situations in which one or more intermediate layers (e.g., layer “C”) is between layer “A” and layer “B” as long as the relevant characteristics and functionalities of layer “A” and layer “B” are not substantially changed by the intermediate layer(s).
The following definitions and abbreviations are to be used for the interpretation of the claims and the specification. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains,” or “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other element not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.
Additionally, the term “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiment or designs. The terms “at least one” and “one or more” can be understood to include any integer number greater than or equal to one, i.e., one, two, three, four, etc. The terms “a plurality” can be understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” can include both indirect “connection” and a direct “connection.”
As used herein, the term “about” modifying the quantity of an ingredient, component, or reactant of the invention employed refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrations or solutions. Furthermore, variation can occur from inadvertent error in measuring procedures, differences in manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods, and the like. The terms “about” or “substantially” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of the filing of the application. For example, about can include a range of ±8%, or 5%, or 2% of a given value. In another aspect, the term “about” means within 5% of the reported numerical value. In another aspect, the term “about” means within 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% of the reported numerical value.
Various process used to form a micro-chip that will packaged into an integrated circuit (IC) fall in four general categories, namely, film deposition, removal/etching, semiconductor doping and patterning/lithography. Deposition is any process that grows, coats, or otherwise transfers a material onto the wafer. Available technologies include physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE), and more recently, atomic layer deposition (ALD) among others. Removal/etching is any process that removes material from the wafer. Examples include etching process (either wet or dry), reactive ion etching (RIE), and chemical-mechanical planarization (CMP), and the like. Semiconductor doping is the modification of electrical properties by doping, for example, transistor sources and drains, generally by diffusion and/or by ion implantation. These doping processes are followed by furnace annealing or by rapid thermal annealing (RTA). Annealing serves to activate the implant dopants. Films of both conductors (e.g. aluminum, copper, etc.) and insulators (e.g. various forms of silicon dioxide, silicon nitride, etc.) are used to connect and isolate electrical components. Selective doping of various regions of the semiconductor substrate allows the conductivity of the substrate to be changed with the application of voltage.
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. Embodiments of the present invention are generally directed to a MRAM that include a magnetic tunnel junction (MTJ). A MTJ consists of two layers of magnetic metal, such as cobalt iron, separated by an ultrathin layer of insulator, typically aluminum oxide with a thickness of about 1 nm. The insulating layer is so thin that electrons can tunnel through the barrier if a bias voltage is applied between the two metal electrodes. In MTJs the tunneling current depends on the relative orientation of magnetizations of the two ferromagnetic layers, which can be changed by an applied magnetic field. MTJs that are based on transition-metal ferromagnets and Al2O3 barriers can be fabricated with reproducible characteristics and with TMR values up to 50% at room temperature. Recently in crystalline MTJs with MgO barriers large values of TMR have been observed further boosting interest in spin dependent tunneling.
MRAM device includes a top contact, a metal hard mask, a MTJ, a diffusion barrier, and a bottom contact. The present invention modifies the bottom contact to include a magnetic material, for example, Co, Ni, ferromagnetic materials, or other magnetic material. The magnetic material in the bottom contact generates a magnetic field that is large enough to affect the free layer of the MTJ. The magnetic field stabilizes the free layer, thus improving the memory stability of the MTJ in the MRAM.
While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.
The descriptions of the various embodiments of the present invention have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the one or more embodiment, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
