Modulation doping-based high-mobility semiconductor device using monolithic oxidation process, and manufacturing method thereof

Abstract

A modulation doping-based high-mobility semiconductor device according to an embodiment of the present invention comprises: a substrate; a channel layer formed on the substrate; a doped layer stacked on the channel layer and band-aligned with the channel layer to be heterojunctioned with the channel layer; an oxide layer formed on the doped layer and a spacer region of the channel layer; and a first electrode and a second electrode coupled to both end portions of the channel layer, respectively, wherein the oxide layer is formed by oxidizing an initial doped layer and the spacer region of the channel layer before an oxidation process through a monolithic oxidation process.

Description

High-mobility semiconductor device based on modulation doping using a monolithic oxidation process and its manufacturing method

[0001] The present invention relates to a high-mobility semiconductor device based on modulation doping using a monolithic oxidation process and a method for manufacturing the same.

[0002] Doping technologies for two-dimensional semiconductors lack the ability to control concentration or doping scattering, and even these are limited to n-type doping. Most doping technologies exhibit degenerate doping characteristics. While applying them to the metal-semiconductor region improves contact resistance, applying them to the channel region can lead to transistor on / off failures.

[0003] In particular, p-type two-dimensional semiconductors have poor contact resistance with electrodes, and it is difficult to manufacture transistors that can improve contact resistance and enable ON / OFF operation in the channel at the same time using current doping technology. In addition, impurity scattering in the channel also causes performance degradation.

[0004] Therefore, the present invention aims to provide a p+ / p- / p+ junction-less high-mobility p-type transistor through a monolithic oxidation process in a heterojunction stacked structure of a two-dimensional semiconductor.

[0005] In addition, the two-dimensional semiconductor is p-doped by the formed oxide film, the channel region is modulated with band-aligned heterojunction stacked structure to suppress impurity scattering, and the metal-semiconductor junction region is degenerately doped to provide a high-mobility p-type transistor with low contact resistance.

[0006] In this regard, as a prior art document, Korean Patent Publication No. 10-2023-0023279 (Title of the invention: High-mobility atomic layer semiconductor device based on modulation doping and method for manufacturing the same) is disclosed.

[0007] In order to solve the above-mentioned problems, the present invention provides a high-mobility p-type two-dimensional semiconductor device with suppressed impurity scattering through a monolithic oxidation process of a two-dimensional semiconductor and modulation doping in a channel region having a band-aligned heterojunction stacked structure, and a method for manufacturing the same.

[0008] However, the technical tasks that this embodiment seeks to accomplish are not limited to the technical tasks described above, and other technical tasks may exist.

[0009] According to one embodiment of the present invention for achieving the above technical task, a high-mobility semiconductor device based on modulation doping comprises: a substrate; a channel layer formed on the substrate; a doping layer stacked on the channel layer and band-aligned with the channel layer to form a heterojunction; an oxide layer formed on a spacer region of the doping layer and the channel layer; and a first electrode and a second electrode respectively bonded to both ends of the channel layer, wherein the oxide layer is formed by oxidizing an initial doping layer and a spacer region of the channel layer before an oxidation process by a monolithic oxidation process.

[0010] In addition, a method for manufacturing a high-mobility semiconductor device based on modulation doping according to another embodiment of the present invention comprises the steps of: stacking a channel layer and a heterojunction doping layer on a substrate, wherein the channel layer and the doping layer form a stacked structure in which the channel layer and the doping layer are band-aligned; forming a first electrode and a second electrode respectively bonded to both ends of the channel layer; and forming an oxide layer on a spacer region of the doping layer and the channel layer, wherein the oxide layer is formed by oxidizing an initial doping layer and a spacer region of the channel layer before an oxidation process by a monolithic oxidation process.

[0011] One embodiment of the present invention enables the production of a transistor capable of ON / OFF with high mobility due to suppression of impurity scattering in a channel and low contact resistance in a p-type two-dimensional semiconductor.

[0012] In addition, while many two-dimensional semiconductor doping technologies use organic compounds in solution, the monolithic oxidation process is a solid-state doping method that can ensure compatibility with existing silicon-based CMOS processes and stability in post-processing.

[0013] FIG. 1 is a cross-sectional view of a high-mobility semiconductor device according to one embodiment of the present invention.

[0014] FIG. 2 is a drawing for explaining a process of forming an oxide layer on a spacer region of a doping layer and a channel layer through a monolithic oxidation process according to one embodiment of the present invention.

[0015] FIG. 3 is an exemplary diagram of a band alignment structure of a high-mobility semiconductor device according to one embodiment of the present invention.

[0016] FIG. 4 is a flowchart for explaining a method for manufacturing a high-mobility semiconductor device according to one embodiment of the present invention.

[0017] FIG. 5 is a drawing illustrating one embodiment of a method for manufacturing a high-mobility semiconductor device of FIG. 4.

[0018] FIG. 6 is a drawing for explaining the structure of a high-mobility semiconductor device according to one embodiment of the present invention.

[0019] FIGS. 7 to 9 are diagrams showing electrical conductivity characteristics of semiconductor devices manufactured according to one embodiment of the present invention.

[0020] Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar reference numerals have been used throughout the specification to indicate similar elements.

[0021] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" but also the case where it is "electrically connected" with another element in between. Furthermore, when a part is said to "include" a component, this should be understood to mean that, unless specifically stated to the contrary, it may include other components rather than excluding them, and does not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0022] FIG. 1 is a cross-sectional view of a high-mobility semiconductor device according to one embodiment of the present invention, and FIG. 2 is a drawing for explaining a process of forming an oxide layer on a spacer region of a doping layer and a channel layer through a monolithic oxidation process according to one embodiment of the present invention.

[0023] Below, the p+ / p- / p+ junctionless high mobility p-type transistor is only one embodiment of the present invention, and various modifications are possible based on the components.

[0024] Referring to FIGS. 1 and 2, a high-mobility semiconductor device based on modulation doping includes a substrate (100), a channel layer (110) formed on the substrate (100), a doped layer (120) stacked on the channel layer (110) and band-aligned with the channel layer (110) and formed as a heterojunction, an oxide layer (121, 111) formed on a spacer region of the doped layer (120) and the channel layer (110), and a first electrode (130) and a second electrode (140) each bonded to both ends of the channel layer (110). In addition, the device may further include an insulating layer (hBN) formed on the lower or upper portion of the stacked structure composed of the channel layer (110) and the doped layer (120).

[0025] In addition, a semiconductor device according to another embodiment of the present invention may further include an insulating layer (150) or a gate layer (160) on the lower or upper portion of a laminated structure composed of a channel layer (110) and a doping layer (120). A detailed structure of a semiconductor device according to a gate structure will be described later with reference to FIG. 6.

[0026] Here, the oxide layer (121) is formed by oxidizing a portion of the initial doping layer (120') prior to the oxidation process through a monolithic oxidation process. Accordingly, after the oxidation process, the initial doping layer (120') can be formed as a multi-layer in which the doping layer (120) and the oxide layer (121) are stacked.

[0027] For example, the channel layer (110) and the doping layer (120) may include at least one material selected from the group of transition metal chalcogenides consisting of MoS2, MoSe2, MoTe2, WS2, WSe2, WTe2, Bi2O2Se, InSe, In2Se3, PdS2, PdSe2, HfS2, HfSe2, ZrS2, and ZrSe2.

[0028] For example, referring to FIG. 2, when a monolithic oxidation process is performed on the initial doping layer (120') during the manufacture of a semiconductor device, only a portion of the upper portion of the initial doping layer (120') may be oxidized to form an oxide layer (121). That is, the oxide layer (121) may be formed by oxidizing and doping a portion of the upper portion of the initial doping layer (120'). Similarly, the oxide layer (111) may be formed by oxidizing and doping a portion of the upper portion of the initial channel layer (110').

[0029] FIG. 3 is an exemplary diagram of a band alignment structure of a high-mobility semiconductor device according to one embodiment of the present invention.

[0030] Referring to FIG. 3, the channel layer (110) may be doped so that holes formed by the oxide layer (121) move along the band alignment, but are spatially separated by the doping layer (120).

[0031] In addition, in a high-mobility semiconductor device based on modulation doping, the thickness of the doping layer (120) after the oxidation process changes according to the thickness change of the initial doping layer (120') before the oxidation process, and the doping concentration of the impurity can be controlled.

[0032] For example, the present invention manufactures a transistor having a two-dimensional semiconductor heterojunction stacked structure as shown in FIG. 2, and can control the doping concentrations of the channel region and the metal-semiconductor junction region, where the channel layer (110) and the doping layer (120) are stacked, differently through the full-scale monolithic oxidation process as shown in FIG. 1.

[0033] As illustrated in Fig. 3, the channel region is formed of a band-aligned heterojunction stacked structure, and holes formed by the upper oxide layer (121) can move to the lower channel layer (110) along the band alignment.

[0034] At this time, the channel layer (110) is spatially separated from the oxide film (121) by the doping layer (120), thereby suppressing impurity scattering, and is covered by the upper doping layer (120), thereby minimizing damage occurring during the oxidation process. In addition, the doping concentration of the lower channel layer (110) can be controlled by adjusting the thickness of the upper doping layer (120), thereby implementing a transistor that can be turned ON / OFF.

[0035] The metal-semiconductor junction region is an area of ​​the channel layer (110) that is exposed without a doping layer (120), and an oxide film (111) is formed on the upper portion of the region through a monolithic oxidation process, and can be degenerately doped. Through this, a p-type transistor with low contact resistance can be manufactured.

[0036] Hereinafter, a method for manufacturing a semiconductor device will be described with reference to FIGS. 4 and 5. In addition, descriptions of components that perform the same function among those described in FIGS. 1 to 3 will be omitted.

[0037] FIG. 4 is a flowchart for explaining a method for manufacturing a high-mobility semiconductor device according to one embodiment of the present invention, and FIG. 5 is a drawing illustrating one embodiment of the method for manufacturing the high-mobility semiconductor device of FIG. 4.

[0038] Referring to FIGS. 2 and 4, a method for manufacturing a high-mobility semiconductor device based on modulation doping according to an embodiment of the present invention includes a step (S110) of stacking a channel layer (110') and a heterojunction initial doping layer (120') on a substrate (100), wherein the channel layer (110') and the initial doping layer (120') form a band-aligned stacked structure, a step (S120) of forming a first electrode (130) and a second electrode (140) respectively bonded to both ends of the channel layer (110), and a step (S130) of forming an oxide layer (121, 111) on a spacer region of the doping layer (120) and the channel layer (110). Here, the oxide film layer (121, 111) is formed by oxidizing the spacer region of the initial doping layer (120') before the oxidation process and the channel layer (110') before the oxidation process through a monolithic oxidation process.

[0039] Step S110 may include a step of forming an insulating layer (150) on the lower or upper portion of a laminated structure composed of a channel layer (110) and a doping layer (120).

[0040] Referring to FIG. 5, in step S110, as shown in FIGS. 5(a) to 5(c), an upper doping layer (MoSe2), a lower channel layer (WSe2), and an insulating layer (hBN) are formed, respectively, and sequentially lifted and laminated using a PC (propylene carbonate) / PDMS (polydemethylsiloxane) stamp. After fabricating a heterojunction laminated structure in this way, in step S120, a source / drain can be deposited using a lithography process, as shown in FIGS. 5(d) to 5(f). Thereafter, a monolithic oxidation process can be performed through an ozone treatment at 100 degrees Celsius for one hour on the entire surface.

[0041] FIG. 6 is a drawing for explaining the structure of a high-mobility semiconductor device according to one embodiment of the present invention.

[0042] For example, as illustrated in FIG. 6(a), a semiconductor device according to an embodiment of the present invention may be formed as a global bottom gate. In this case, the gate may be disposed at the lower portion closest to the substrate (100). As illustrated in FIG. 6(b), a semiconductor device according to another embodiment of the present invention may be formed as a top gate. In this case, an insulating layer (150) and a gate layer (160) may be disposed on top of an oxide layer (121). As illustrated in FIG. 6(c), a semiconductor device according to another embodiment of the present invention may be formed as a local bottom gate. In this case, an insulating layer (150) may be disposed under a channel layer (110), and a gate layer (160) may be disposed in a lower region of the insulating layer (150).

[0043] FIGS. 7 to 9 are diagrams showing electrical conductivity characteristics of semiconductor devices manufactured according to one embodiment of the present invention.

[0044] As illustrated in Fig. 7, a semiconductor device manufactured according to one embodiment of the present invention exhibits a low contact resistance of 1.33 kΩ·μm.

[0045] As shown in Fig. 8, the modulation doping concentration of the channel changes depending on the thickness of the upper doping layer (MoSe2).

[0046] As illustrated in FIG. 9, when comparing the mobility and surface electrical conductivity of a modulation doped (MD) device manufactured according to one embodiment of the present invention with a conventional direct doped (DD) device, the modulation doped device shows results that are more than twice as improved.

[0047] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0048] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. In high-mobility semiconductor devices based on modulation doping, substrate; A channel layer formed on the above substrate; A doping layer laminated on the channel layer and formed into a heterojunction with the channel layer and band-aligned with the channel layer; An oxide layer formed on the spacer region of the above doping layer and channel layer; and Including a first electrode and a second electrode respectively coupled to both ends of the channel layer, A high-mobility semiconductor device based on modulation doping, wherein the oxide film layer is formed by oxidizing the spacer region of the initial doping layer and the channel layer before the oxidation process by a monolithic oxidation process.

2. In paragraph 1, The above channel layer A high-mobility semiconductor device based on modulation doping, wherein holes formed by the oxide layer move along the band alignment, but are spatially separated and doped by the doping layer.

3. In paragraph 1, The above doping layer A high-mobility semiconductor device based on modulation doping, wherein the thickness of the doped layer after the oxidation process changes according to the thickness change of the initial doped layer before the oxidation process, and the doping concentration of the impurity is controlled.

4. In paragraph 1, A high-mobility semiconductor device based on modulation doping, further comprising an insulating layer formed on the lower or upper side of a laminated structure composed of the channel layer and the doping layer.

5. In a method for manufacturing a high-mobility semiconductor device based on modulation doping, A step of stacking a channel layer and an initial doping layer heterojunction on a substrate, wherein the channel layer and the initial doping layer form a band-aligned stacked structure; A step of forming a first electrode and a second electrode respectively coupled to both ends of the channel layer; and Comprising a step of forming an oxide layer on the spacer region of the initial doping layer and the channel layer, A method for manufacturing a high-mobility semiconductor device based on modulation doping, wherein the oxide film layer is formed by oxidizing the spacer region of the initial doping layer and the channel layer before the oxidation process by a monolithic oxidation process.

6. In paragraph 5, The above channel layer A method for manufacturing a high-mobility semiconductor device based on modulation doping, wherein holes formed by the oxide layer move along the band alignment, but are spatially separated and doped by the doping layer.

7. In paragraph 5, The above doping layer A method for manufacturing a high-mobility semiconductor device based on modulation doping, wherein the thickness of the doped layer after the oxidation process is changed according to the thickness change of the initial doped layer before the oxidation process, and the doping concentration of the impurity is controlled.

8. In paragraph 5, A method for manufacturing a high-mobility semiconductor device based on modulation doping, wherein, when forming the above-described laminated structure, the method further includes a step of forming an insulating layer on the lower or upper portion of the laminated structure composed of the channel layer and the doping layer.

Images