KR101050228B1 - Nitride semiconductor device and method for forming same - Google Patents

Abstract

The present invention relates to a nitride semiconductor device and a method for forming the same, the present invention includes a substrate having a buffer layer, a 2DEG layer and a barrier layer; Source and drain gate electrodes formed in the active region of the substrate; And a body electrode formed to be in contact with the buffer layer around the active region, and a method of forming the nitride semiconductor device. In this case, since the body electrode is formed to surround the active region, it is possible to effectively remove the hot carrier.

2DEG, Buffer Layer, Hot Carrier, Body Electrode

Description

A nitride semiconductor device and a method for forming the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor devices, and in particular, to nitride semiconductor devices and methods for forming the same.

A nitride semiconductor device according to the prior art will be described. 1 is a view for explaining a nitride semiconductor device according to the prior art.

As shown, the nitride semiconductor has a structure in which a buffer layer 2, a 2DEG layer 3, and a barrier layer 4 are sequentially stacked on the substrate 1, and the source, drain, and gate electrodes 5, 6, 7 ) Is formed.

In particular, the 2DEG layer 3 is the path of migration of electrons from the source 5 to the drain 6.

In the semiconductor device according to the related art, as shown in the drawing, collision of electrons increases as the drain voltage increases, and thus hot carriers are generated. The generated hot carriers do not move along the 2DEG layer 3 but move to the buffer layer 2. When these hot carriers accumulate, an abnormality in the current may occur, and hot holes may be generated in addition to the hot electrons.

Accordingly, an object of the present invention in view of the above-described conventional problems is to provide a semiconductor nitride device and a method of manufacturing the same that can easily remove hot carriers that may occur at high voltages.

According to an embodiment of the present invention, a nitride semiconductor device includes: a substrate on which a buffer layer, a 2DEG layer, and a barrier layer are formed; Source, drain, and gate electrodes formed in the active region of the substrate; And a body electrode formed to contact the buffer layer around the active region.

The active region refers to a substrate region in which the 2DEG layer is present, and includes at least one source, drain, and gate electrode in the active region, and the body electrode is formed outside the active region.

The buffer layer is formed of any one selected from a stacked structure of GaN and AlGaN and GaN.

The body electrode may be formed to surround the active region.

The source, drain and body electrodes are heat treated to have ohmic contacts.

The gate electrode is characterized in that it is formed to have a schottky contact (schottky contact).

According to an embodiment of the present invention, a method of forming a nitride semiconductor device may include forming a structure in which a buffer layer, a 2DEG layer, and a barrier layer are stacked on a substrate, and forming an active region of the substrate. Forming a source and a drain gate electrode, and forming a body electrode to contact the buffer layer around the active region.

Forming a protective layer to cover the electrodes, removing the protective layer to expose a portion of the upper surface of the electrodes, and forming a metal contact in contact with the upper surface of the exposed electrodes, wherein a portion of the metal contact is formed The source electrode and the body electrode further comprises the step of electrically connecting using a metal contact.

The buffer layer is formed of any one selected from a stacked structure of GaN and AlGaN and GaN.

The active region refers to a substrate region in which the 2DEG layer is present, and includes at least one source, drain, and gate electrode in the active region, and the body electrode is formed outside the active region.

In the process of forming the body electrode, the body electrode is characterized in that it is formed in a form surrounding the active region.

The source, drain and body electrodes are heat treated to have ohmic contacts.

The gate electrode is formed to have a schottky contact.

As described above, according to the present invention, the body electrode is formed by ohmic, and the formed body electrode has a guard ring layout surrounding the active region. Accordingly, the hot carrier can be effectively removed. The present invention can effectively remove hot carriers accumulated in the buffer layer when applying a high voltage, thereby preventing abnormal currents and expecting stable operating characteristics even under high voltage conditions.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

2 and 3 are views for explaining the structure of the nitride semiconductor device according to an embodiment of the present invention. 2 is a cross-sectional view of a nitride semiconductor device according to an embodiment of the present invention, and FIG. 3 is a plan view of a nitride semiconductor device according to an embodiment of the present invention. 2 is a plan view excluding a metal wiring part (metal contact 500) to clarify the shape of the body electrode, the source, the drain, and the gate electrode.

2 and 3, in the nitride semiconductor device according to an embodiment of the present invention, a buffer layer 110, a 2DEG layer 120, and a barrier layer 130 are sequentially stacked on a substrate 100 to be formed. do. In addition, the source, drain, and gate electrodes 210, 220, and 300 are formed in the active region of the device, and the body electrode 230 is formed to surround the active region and to contact the buffer layer 110. In this case, the body electrode 230 is formed like the source and drain electrodes 210 and 220. The gate and the body electrode 230 are separated by the protective layer 400. The active region refers to a substrate region in which the 2DEG layer 120 is present, and includes at least one source, drain, and gate electrodes 210, 220, and 300 in the active region. Body electrode 230 is formed outside the active region.

In the nitride semiconductor device according to the embodiment of the present invention, the source and drain electrodes 210, 220, and 230 form ohmic contacts, and the gate electrode 300 forms a schottky contact.

In particular, according to an embodiment of the present disclosure, by forming a body electrode 230 having an ohmic contact around the active region, hot carriers generated in the buffer layer 110 may be easily removed. That is, since the body electrode 230 serves to induce hot carriers generated in the buffer layer 110 and is formed together with the source and drain electrodes 210 and 220, a process is easy and no additional heat treatment is required.

In addition, by forming a structure in which the body electrode 230 surrounds the active region of the device, the body electrode 230 does not remove hot carriers generated in some areas of the device, but rather the entire area of the device like a guard ring. Hot carriers occurring at can be removed.

Next, a nitride semiconductor forming method according to an embodiment of the present invention will be described. 4 is a flowchart illustrating a method of forming a nitride semiconductor according to an embodiment of the present invention, and FIGS. 5A to 5E are views illustrating a method of forming a semiconductor according to an embodiment of the present invention.

Referring to FIG. 4, the substrate 100 is prepared in step S401. As the substrate 100, a substrate such as silicon (Si), sapphire (Al 2 O 3), silicon carbide (SiC), or the like may be used. Then, in step S403 to form a buffer layer 110 having a transition layer and a high resistance layer on the substrate 100. The buffer layer 110 is preferably formed of gallium nitride (GaN), and the thickness thereof may be adjusted within a range of 0.5 to 15 μm. Formation of the buffer layer 110 may be an epitaxial growth method. For example, the buffer layer 110, which is an epitaxial layer of gallium nitride, may be grown using trimethylgalluim (TMG) and ammonia as Ga and N sources and hydrogen as a carrier gas at temperatures of 800 to 1200 ° C. have.

Subsequently, in operation S405, the barrier layer 130 is formed on the buffer layer 110 to generate the 2DEG layer 120. The barrier layer 130 is preferably AlGaN as a material having a band gap larger than that of the buffer layer 110. Since AlGaN has a larger band gap than GaN, free charge transfer from the larger band gap to the smaller band gap material occurs due to the discontinuities of the upper and lower layers 110 and 130 in the energy band gap. The charge accumulates at the interface between these layers 110 and 130 to form a two dimensional electron gas (2DEG) layer (hereinafter abbreviated as " 2DEG layer ") that allows current to flow between the source and drain. Create

The barrier layer 130 may be by an epitaxial growth method. For example, it may be made by MOCVD using TMG (Trimethylgallium), TMA (Trimethylalluminium), and ammonia as sources of Ga, Al, and N, respectively, at a temperature of 900 ° C. or higher, but is not limited thereto.

Thus, the structure in which the buffer layer, the 2DEG layer, and the barrier layer are sequentially stacked on the substrate is shown in FIG. 5A.

Subsequently, in step S407, the barrier layer 130, the 2DEG layer 120, and the buffer layer 110 are etched to expose a portion of the buffer layer 110, as shown in FIG. 5B. To separate them. The etching method may be both wet etching and dry etching.

Next, in step S409, as shown in FIG. 5C, source, drain, and body electrodes 210, 220, and 230 having ohmic contacts are formed.

The source, drain, and body electrodes 210, 220, and 230 are formed to contact the buffer layer 110. In particular, the source and drain electrodes 210 and 220 are etched after the barrier layer 130, the 2DEG layer 120, and the buffer layer 110 are exposed to expose the buffer layer 110 so as to be in contact with the buffer layer 110. Source and drain electrodes 210 and 220 may be formed.

Each of the source, drain, and body electrodes 210, 220, and 230 may be formed in a structure in which Ti, Al, NI, and Au are sequentially stacked. After forming the electrodes 210, 220, and 230, heat treatment is performed to have low ohmic characteristics. The heat treatment is preferably carried out at 900 ℃ for 30 sec.

Subsequently, as shown in FIG. 5D in step S411, the gate electrode 300 is formed on the barrier layer 130. The gate electrode 300 may adopt a structure in which Ni and Au are stacked to have a schottky contact characteristic.

As described above, the source, drain, body, and gate electrodes 210, 220, 230, and 300 are covered on the substrate on which the source, drain, body, and gate electrodes 210, 220, 230, and 300 are formed. The protective layer 400 is formed. The protective layer 400 may be formed of nitride, for example, silicon nitride (SixNy). In addition, the protective layer 400 can be formed by a sputtering method or the like.

Subsequently, in operation S415, the upper portion of the passivation layer 400 is exposed to form a metal contact 500 connected to each of the source, drain, body, and gate electrodes 210, 220, 230, and 300, respectively. At this time, the source layer, the drain, the body and the gate electrode 210, 220, 230, 300 by etching the protective layer 400 so as to expose a portion of the upper surface, respectively, by embedding a metal film, each source, drain, body and gate electrode ( Metal contacts 500 are formed to be electrically connected to 210, 220, 230, and 300. This result is shown in FIG. 5E.

6 is a view for explaining a method of forming a nitride semiconductor according to another embodiment of the present invention.

Referring to FIG. 6, the source, drain, body, and gate electrodes 210, 220, 230, and 300 are separated from each other in the previous embodiment, but the roles of the source and body electrodes 210 and 230 are the same, so that the metal contact is performed. The source and body electrodes 210 and 230 may be electrically connected to each other by using the 500. That is, the source and body electrodes 210 and 230 have the same voltage by using the metal contact 500.

The present invention as described above forms a body electrode in ohmic, the formed body electrode has a guard ring layout surrounding the active area. Accordingly, the hot carrier can be effectively removed. According to the present invention, it is possible to effectively remove the hot carriers accumulated in the buffer layer when applying a high voltage, to prevent the abnormality of the current and to expect stable operating characteristics even at high voltage conditions.

While the present invention has been described with reference to several preferred embodiments, these embodiments are illustrative and not restrictive. As such, those of ordinary skill in the art will appreciate that various changes and modifications can be made according to equivalents without departing from the spirit of the present invention and the scope of rights set forth in the appended claims.

1 is a view for explaining a nitride semiconductor device according to the prior art.

2 and 3 are views for explaining the structure of the nitride semiconductor device according to an embodiment of the present invention.

4 is a flowchart illustrating a method of forming a nitride semiconductor according to an embodiment of the present invention.

5A to 5E are diagrams for describing a method of forming a semiconductor according to an embodiment of the present invention.

6 is a view for explaining a nitride semiconductor forming method according to another embodiment of the present invention.

Claims (13)

A substrate on which a buffer layer, a 2DEG layer, and a barrier layer are formed; Source, drain, and gate electrodes formed in the active region of the substrate; And A body electrode formed to contact the buffer layer around the active region, The body electrode is nitride semiconductor device, characterized in that formed in the form surrounding the active region. The method of claim 1 The active region means a substrate region in which the 2DEG layer exists. And at least one of the source, drain and gate electrodes in the active region, wherein the body electrode is formed outside the active region. The method of claim 1, The buffer layer is formed of any one selected from a stacked structure of GaN and AlGaN and GaN nitride semiconductor device. delete The method of claim 1, And the source, drain, and body electrodes are heat treated to have ohmic contacts. The method of claim 1, And the gate electrode is formed to have a schottky contact. Forming a structure in which a buffer layer, a 2DEG layer, and a barrier layer are stacked on a substrate; A method of forming a nitride semiconductor device comprising forming a source electrode, a drain electrode, a gate electrode in an active region of the substrate, and forming a body electrode in contact with the buffer layer around the active region. In the process of forming the body electrode, The body electrode is nitride semiconductor device forming method characterized in that it is formed in a form surrounding the active region. Forming a structure in which a buffer layer, a 2DEG layer, and a barrier layer are stacked on a substrate; A method of forming a nitride semiconductor device comprising forming a source electrode, a drain electrode, a gate electrode in an active region of the substrate, and forming a body electrode in contact with the buffer layer around the active region. Forming a protective layer to cover the electrodes; Removing the protective layer to expose a portion of the upper surface of the electrodes; Form a metal contact in contact with the upper surface of the exposed electrodes, And forming a portion of the metal contact, wherein the source electrode and the body electrode are electrically connected to each other using a metal contact. The method of claim 7, wherein The buffer layer is formed of a nitride semiconductor device, characterized in that formed of any one selected from a stacked structure of GaN and AlGaN and GaN. The method of claim 7, The active region means a substrate region in which the 2DEG layer exists. And at least one source, drain, and gate electrode in the active region, wherein the body electrode is formed outside the active region. delete The method of claim 7, wherein And the source, drain and body electrodes are heat treated to have ohmic contacts. The method of claim 7, wherein And the gate electrode is formed to have a schottky contact.

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