This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2012-0121385, filed on Oct. 30, 2012, in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to semiconductor devices and methods of manufacturing the same and, more particularly, to a phase change memory device and methods of manufacturing the phase change memory device. More particularly, the present disclosure relates to a phase change memory device having improved electrical characteristics and reliability and a method of manufacturing the phase change memory device.
Semiconductor memory devices are generally divided into volatile semiconductor memory devices such as dynamic random access memory (DRAM) devices or static random access memory (SRAM) devices, and non-volatile semiconductor memory devices such as flash memory devices or electrically erasable programmable read only memory (EEPROM) devices. The volatile semiconductor memory device loses data stored therein when power is off. The non-volatile semiconductor memory device keeps stored data even if power is out.
Among the non-volatile semiconductor memory devices, the flash memory device has been widely employed in various electronic apparatuses such as a digital camera, a cellular phone, an MP3 player, etc. Since a programming process and a reading process of the flash memory device take a relatively long time, technologies to manufacture a novel semiconductor memory device, for example a magnetic random access memory (MRAM) device, a ferroelectric random access memory (FRAM) device, and a phase-change random access memory (PRAM) device, have been constantly developed.
The present disclosure relates to semiconductor devices and methods of manufacturing the same.
In one embodiment, a method of forming a phase change memory device is disclosed. The method includes forming a first ion-implanted layer having an amorphous state in a substrate; forming an impurity region of a first conductive type in the substrate; forming a semiconductor pattern on the substrate; forming a first doped region of the first conductive type in the semiconductor pattern; and forming a second doped region of a second conductive type contrary to the first conductive type in the semiconductor pattern. The first ion-implanted layer is formed by implanting carbons ions or germanium ions in the substrate.
In another embodiment, a method of manufacturing a phase-change memory device, includes providing a substrate; forming an impurity region of a first conductive type in the substrate, the impurity region extending from the top surface of the substrate into the substrate; forming a semiconductor pattern on the substrate; forming a first doped region of the first conductive type in the semiconductor pattern; forming a layer having an amorphous state in the substrate; and forming a second doped region of a second conductive type contrary to the first conductive type in the semiconductor pattern. The layer controls the amount of doping that occurs at least in the second doped region.
In another embodiment, a semiconductor device includes a substrate; a first ion-implanted layer in the substrate, the first ion-implanted layer having an amorphous state;
an impurity region in the substrate, the impurity region of a first conductive type; a semiconductor pattern on the substrate; a first doped region of the first conductive type in the semiconductor pattern; and a second doped region of a second conductive type contrary to the first conductive type in the semiconductor pattern. The first ion-implanted layer includes implanted carbon ions or germanium ions in the substrate.
Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings.
a through 18c are graphs illustrating characteristics of a phase change memory device according to exemplary embodiments.
The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. The advantages and features of the present disclosure and methods of achieving them will be apparent from the following exemplary embodiments that will be described in more detail with reference to the accompanying drawings. It should be noted, however, that the inventive concept is not limited to the following exemplary embodiments, and may be implemented in various forms. In the drawings, embodiments are not limited to the specific examples provided herein and are exaggerated for clarity.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular terms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present.
Similarly, it will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present. In contrast, the term “directly” means that there are no intervening elements. It will be further understood that the terms “comprises”, “comprising,” “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Additionally, the embodiment in the detailed description will be described with sectional views as ideal exemplary views. Accordingly, shapes of the exemplary views may be modified according to manufacturing techniques and/or allowable errors. Therefore, the embodiments disclosed herein are not limited to the specific shape illustrated in the exemplary views, but may include other shapes that may be created according to manufacturing processes. Areas exemplified in the drawings have general properties, and are used to illustrate specific shapes of elements. Thus, this should not be construed as limiting the scope of the inventive concept.
It will be also understood that although the terms first, second, third etc. may be used herein to describe various elements, these elements should not be limited by these terms. Unless indicated otherwise, these terms are only used to distinguish one element from another element. Thus, a first element in some embodiments could be termed a second element in other embodiments without departing from the teachings disclosed herein. Exemplary embodiments of aspects explained and illustrated herein include their complementary counterparts. The same reference numerals or the same reference designators denote the same elements throughout the specification.
Moreover, exemplary embodiments are described herein with reference to cross-sectional illustrations and/or plane illustrations that are idealized exemplary illustrations. Accordingly, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etching region illustrated as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to limit the scope of example embodiments.
The phase change memory device may be, for example, a data storage device for storing data. As illustrated in
The p-type semiconductor region of the PN junction diode may be electrically connected to one end of the phase change resistor Rp, and the other end of the phase change resistor Rp may be electrically connected to one of the bit lines (BL). The n-type semiconductor region of the PN junction diode may be electrically connected to one of the word lines (WL).
According to exemplary embodiments, when the substrate 100 initially has a structure of a single crystal, the first ion-implanted layer 105 may include a silicon and ion-implanted carbon or germanium. As a result, as ion-implanted carbon or germanium atoms are arranged between silicon atoms of a single crystal state, atomic arrangement of the first ion-implanted layer 105 may be changed from the single crystal state to an amorphous state. In certain embodiments, the first ion-implanting process may include an ion-implantation method or a PLAD (Plasma Doping) method. In one embodiment, the first ion-implanting process maintains a doping concentration of the substrate 100 by implanting ions of group 4 elements. In one embodiment, the first ion-implanted layer 105 may be formed from the top surface of the substrate 100 to a distance below the surface of the substrate 100.
Referring to
As such, according to exemplary embodiments, the impurity region 102 may be formed more deeply in the substrate than the first ion-implanted layer 105. The impurity region 102 may be formed by implanting, for example, arsenic or phosphorus ions within the substrate 100. The impurity region 102 may be formed by an ion-implantation method, but is not limited thereby. The first ion-implanted layer 105 formed in the upper portion of the substrate 100 can have an atomic arrangement of an amorphous state, and may include impurities such as arsenic or phosphorus ions. In one embodiment, the first ion-implanted layer 105 has a higher number or greater concentration of arsenic or phosphorus ions than the portion of the impurity region 102 below the first ion-implanted layer.
Note that although the layers are described above and in the figures as having clear boundaries, in certain embodiments, the boundaries between regions may be gradual and not linear step-wise. As such, the impurity region 102 may be thought of as ending not at a rigid line, but at a point where a concentration of impurities 102 is below a particular level. A similar boundary may exist for the first ion-implanted layer 105.
In one embodiment, as described and shown in
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According to exemplary embodiments, the first ion-implanting process may be performed before forming the insulation pattern 110 or after forming the insulating pattern 110.
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According to exemplary embodiments, the first doped region 122 may be formed by performing additional heat treatment after forming the semiconductor layer 120. The first doped region 122 may be formed as impurities of the first impurity region 102 having the first conductive type of high concentration are diffused by thermal energy produced by the heat treatment.
The semiconductor layer 120 may have an atomic arrangement of single crystal or crystalline state as a result of thermal energy produced in the process of SEG or additional heat treatment.
Referring to
According to exemplary embodiments, the second ion-implanting process may include ion-implantation method or PLAD (Plasma Doping) method. The second ion-implanted layer 106 may be selectively formed at various depths in the semiconductor layer 120. For example, the second ion-implanted layer 106 may be formed directly on the first doped region 122 (e.g., above and immediately adjacent to the first doped region 122). The second ion-implanted layer 106 may therefore control the concentration profile of impurities in a second doped region. For example, the second ion-implanted layer 106 may limit the impurities that diffuse from the first doped region 122 to the remainder of the semiconductor layer 120. Similarly, if the remainder of the semiconductor layer 120 is doped with other impurities, as will be described below, the second ion-implanted layer 106 may limit those impurities from diffusing into the first doped region 122. In one embodiment, the second ion-implanted layer 106 may be formed in the upper portion of the first semiconductor layer 120 (e.g., in an upper half of the semiconductor layer 120). However, the second ion-implanted layer 106 can be formed at other locations within the first semiconductor layer 120.
Referring to
According to exemplary embodiments, the second doped region 124 may be formed by PLAD (Plasma Doping) method. The second doped region 124 may be formed by doping atoms ionized in the plasma state, which can adjust the doping concentration more easily than conventional ion beam implantation method, and can improve productivity resulting from a short process time. The second doped region 124 may be formed, for example, by using diborane (B2H6) gas or boron trifluoride (BF3) gas in a plasma chamber.
According to exemplary embodiments, the first doped region 122 and the second doped region 124 may be formed in the semiconductor layer 120. The first doped region 122 may be formed in the lower portion of the semiconductor layer 120 and the second doped region 124 may be formed in the upper portion of the semiconductor layer 120. The semiconductor layer 120 in which the first doped region 122 and the second doped region 124 are formed may go through heat treatment to form the first doped region 122 and the second doped region 124. The semiconductor layer 120 may include a PN junction diode 125 including the first doped region 122 and the second doped region 124 having opposite conductive types. The PN junction diode 125 may play a role, for example, as a switch of phase change memory device.
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According to exemplary embodiments, the doping concentration of the first and the second doped regions 122, 124 may be lower compared to conventional technologies. Furthermore, the height to which doping occurs may be lower as well. As a result, the connection area of the first and the second doped regions 122, 124 may be narrowed and may have a lower concentration of impurities. As the first ion-implanted layer 105 is formed through the first ion-implanting process performed before forming the first doped region 122, ion-implanted carbon or germanium atoms are arranged between silicon atoms of a single crystal state in the substrate 100, so arrangement of silicon atoms may be changed from the single crystal state to an amorphous state. As the diffusion of doping areas by thermal energy progresses slowly, the diffusion may be decreased by the first ion-implanted layer 105. Similarly, as the second ion-implanted layer 106 of
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a through 18c are graphs illustrating characteristics of a phase change memory device according to exemplary embodiments.
a is a graph of an operating voltage (Von) according to current in a case of forming the second doped region using plasma. As explained in
b is a graph of off current according to voltage in case of the first ion-implanted layer before forming the first doped region. As explained in
The embodiments and methods described above can be used in various different types of semiconductor memory devices. For example, the semiconductor memory device may include Package on Package (PoP), Ball Grid Arrays (BGAs), Chip Scale Packages (CSPs), Plastic Leaded Chip Carrier (PLCC), Plastic Dual In-Line Package (PDIP), Die in Waffle Pack, Die in Wafer Form, Chip On Board (COB), Ceramic Dual In-Line Package (CERDIP), Plastic Metric Quad Flat Pack (MQFP), Thin Quad Flatpack (TQFP), Small Outline (SOIC), Shrink Small Outline Package (SSOP), Thin Small Outline (TSOP), System In Package (SIP), Multi Chip Package (MCP), Wafer-Level Fabricated Package (WFP), or Wafer-Level Processed Stack Package (WSP).
A semiconductor memory device according to the exemplary embodiments may be in the form of a package that may include one or more controllers and/or logic devices controlling the semiconductor memory device.
Referring to
The controller 1110 may include at least one of a microprocessor, a digital signal processor, a microcontroller, or another logic device. The other logic device may have a similar function to any one of the microprocessor, the digital signal processor, and the microcontroller. The I/O unit 1120 may include a keypad, a keyboard, and/or a display unit. The memory device 1130 may store data and/or commands. The memory device 1130 may include at least one of the phase change memory devices and/or data storage devices according to the embodiments described above. The memory device 1130 may further include other types of semiconductor memory devices, which are different from the semiconductor memory devices described above. For example, the memory device 1130 may further include a non-volatile memory device and/or a static random access memory (SRAM) device. In one embodiment, the interface unit 1140 may transmit electrical data to a communication network or may receive electrical data from a communication network. The interface unit 1140 may be operated by wireless or cable. For example, the interface unit 1140 may include an antenna for wireless communication or a transceiver for cable communication. Although not shown in the drawings, the electronic system 1100 may further include a fast DRAM device and/or a fast SRAM device, which acts as a cache memory for improving an operation of the controller 1110.
The electronic system 1100 may be applied, for example, to a personal digital assistant (PDA), a portable computer, a web tablet, a wireless phone, a mobile phone, a digital music player, a memory card, or other electronic products. The other electronic products may receive or transmit information data, for example, by wired or wireless signals.
Referring to
The memory controller 1220 may include a central processing unit (CPU) 1222 that controls overall operations of the memory card 1200. In addition, the memory controller 1220 may include an SRAM device 1221 used as an operation memory of the CPU 1222. Moreover, the memory controller 1220 may further include a host interface unit 1223 and a memory interface unit 1225. The host interface unit 1223 may be configured to include a data communication protocol between the memory card 1200 and the host. The memory interface unit 1225 may connect the memory controller 1220 to the memory device 1210. The memory controller 1220 may further include an error check and correction (ECC) block 1224. The ECC block 1224 may detect and correct errors of data which are read out from the memory device 1210. Even though not shown in the drawings, the memory card 1200 may further include a read only memory (ROM) device that stores code data to interface with the host. The memory card 1200 may be used, for example, as a portable data storage card. Alternatively, the memory card 1200 may be realized as solid state disks (SSD) which are used as hard disks of computer systems.
While the disclosure has been described with reference to example embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the inventive concept. Therefore, it should be understood that the above embodiments are not limiting, but illustrative. Thus, the scope of the inventive concept is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing description.
Number | Date | Country | Kind |
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10-2012-0121385 | Oct 2012 | KR | national |