Semiconductor device

Disclosed herein is a semiconductor device including: a source electrode formed on one side of an N-type AlGaN layer; N-type and P-type AlGaN layers formed on the other side of the P-type AlGaN layer and formed in a direction perpendicular to the source electrode; a gate electrode formed on one side of the N-type and P-type AlGaN layers; and a drain electrode formed on the other side of the N-type and P-type AlGaN layers.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2012-0119857, filed on Oct. 26, 2012, entitled “Semiconductor Device”, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a semiconductor device.

2. Description of the Related Art

Various nitride semiconductor devices including the semiconductor device disclosed in Patent Document 1 have a number of advantages such as high breakdown electric field, high electron mobility, high temperature operation, high thermal conductivity, and the like, to be widely used in a high voltage device, a high frequency device, or the like.

Among these devices, a field effect transistor (hereinafter, referred to as FET) device has a limitation in a spaced distance between a source terminal and a drain terminal for securing breakdown capability.

If the spaced distance between the source terminal and the drain terminal is large, at the time of turning-on the FET device, turn-on resistance is large due to an increase in the spaced distance between the source terminal and the drain terminal.

In other words, there is a trade-off relation between the breakdown capacity and the turn-on resistance.

Meanwhile, the semiconductor device is required to secure the spaced distance having a predetermined distance or larger for securing breakdown voltage between the source terminal and the drain terminal, and the longer the spaced distance, the larger the resistance between the source terminal and the drain terminal.

Therefore, in order to decrease the resistance between the source terminal and the drain terminal, the spaced distance therebetween is required to be decreased; however, in this case, it is difficult to secure the breakdown voltage.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1 US 2006-0049426 A

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a semiconductor device having a structure in which a gate terminal and a drain terminal are improved to increase operational reliability of the semiconductor device.

According to a preferred embodiment of the present invention, there is provided a semiconductor device including: an undoped Group III-V first semiconductor layer; a first conductive Group III-V second semiconductor layer formed on the undoped Group III-V first semiconductor layer; a first electrode formed on one side of the first conductive Group III-V second semiconductor layer; first and second conductive Group III-V second semiconductor layers formed on the other side of the first conductive Group III-V second semiconductor layer and formed in a direction perpendicular to the first electrode; a second electrode formed on one side of the first and second conductive Group III-V second semiconductor layers; and a third electrode formed on the other side of the first and second conductive Group III-V second semiconductor layers, wherein the first conductive Group III-V second semiconductor layer and the second conductive Group III-V second semiconductor layer are alternately formed.

The number of first conductive Group III-V second semiconductor layer and the number of second conductive Group III-V second semiconductor layer may be in plural, respectively.

A width of the first conductive Group III-V second semiconductor layer and a width of the second conductive Group III-V second semiconductor layer in a direction of the first electrode may be the same.

The first conductive Group III-V second semiconductor layer and the second conductive III-V second semiconductor layer may have the same concentration.

The undoped Group III-V first semiconductor layer may be made of GaN material.

The Group III-V second semiconductor layer may be made of an AlGaN material.

The first conductive Group III-V second semiconductor layer may be N-type, and the second conductive Group III-V second semiconductor layer may be P-type.

The first electrode may be a source electrode, a second electrode may be a gate electrode, and a third electrode may be a drain electrode.

The second electrode and the third electrode may be formed in a horizontal direction of the first electrode, respectively.

According to another preferred embodiment of the present invention, there is provided a semiconductor device including: an undoped GaN layer; a first conductive AlGaN layer formed on the undoped GaN layer; a source electrode formed on one side of the first conductive AlGaN layer; first and second conductive AlGaN layers formed on the other side of the first conductive AlGaN layer and formed in a direction perpendicular to the source electrode; a gate electrode formed on one side of the first and second conductive AlGaN layers; and a drain electrode formed on the other side of the first and second conductive AlGaN layers, wherein the first conductive AlGaN layer and the second conductive AlGaN layer are alternately formed.

The number of first conductive AlGaN layer and the number of second conductive AlGaN layer may be in plural, respectively.

A width of the first conductive AlGaN layer and a width of the second conductive AlGaN layer in a direction of the source electrode may be the same.

The first conductive AlGaN layer and the second conductive AlGaN layer may have the same concentration.

The first conductive AlGaN layer may be N-type, and the second conductive AlGaN layer may be P-type.

The gate electrode and the drain electrode may be formed in a horizontal direction of the source electrode, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The objects, features and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side” and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the related art would obscure the gist of the present invention, the description thereof will be omitted.

The semiconductor device disclosed in the description of the preferred embodiments may be a field effect transistor, but the present invention is not limited thereto.

Semiconductor Device

FIG. 1is a view showing a configuration of a semiconductor device according to a preferred embodiment of the present invention.

As shown inFIG. 1, the semiconductor device100may include: an undoped Group III-V first semiconductor layer110; a first conductive Group III-V second semiconductor layer120formed on the undoped Group III-V first semiconductor layer110; a first electrode141formed on one side of the first conductive Group III-V second semiconductor layer120; first and second conductive Group III-V second semiconductor layers133and131formed on the other side of the first conductive Group III-V second semiconductor layer120and formed in a direction perpendicular to the first electrode141; a second electrode143formed on one side of the first and second conductive Group III-V second semiconductor layers133and131; and a third electrode145formed on the other side of the first and second conductive Group III-V second semiconductor layers133and131.

Here, the first conductive Group III-V second semiconductor layer133and the second conductive Group III-V second semiconductor layer131may be alternately formed.

In addition, as shown inFIG. 1, the number of first conductive Group III-V second semiconductor layer133and the number of second conductive Group III-V second semiconductor layer131may be in plural, respectively.

In this case, as shown inFIG. 1, the first conductive Group III-V second semiconductor layer133and the second conductive Group III-V second semiconductor layer131may be sequentially and alternately formed, respectively. For example, the semiconductor device100has a structure obtained by forming the second conductive Group III-V second semiconductor layer131, then forming the first conductive Group III-V second semiconductor layer133so as to be contacted to the second conductive Group III-V second semiconductor layer, and repeating these formations.

Meanwhile, the above-described Group III-V first semiconductor layer may be made of a GaN material.

In addition, the Group III-V second semiconductor layer may be made of an AlGaN material.

Further, the first conductive semiconductor layer may be an N-type, and the second conductive semiconductor layer may be a P-type.

In addition, the first electrode141may be a source electrode, the second electrode143may be a gate electrode, and the third electrode145may be a drain electrode.

In addition, as shown inFIG. 1, a width (Wn) of the first conductive Group III-V second semiconductor layer133and a width (Wp) of the second conductive Group III-V second semiconductor layer131in a direction of the first electrode141may be the same. For example, the width (Wn) of the first conductive Group III-V second semiconductor layer133and the width (Wp) of the second conductive Group III-V second semiconductor layer131shown inFIG. 1are the same.

Here, the term ‘same’ does not mean thickness of dimensions that are accurately the same in mathematics, but means the thickness of dimensions that are substantially the same in consideration of errors in design, in manufacture, in measurement, or the like.

In addition, the first conductive Group III-V second semiconductor layer133and the second conductive Group III-V second semiconductor layer131have the same concentration.

That is, at the time of reverse bias, since a stripe structure (alternate structure) of the first conductive Group III-V second semiconductor layer133and the second conductive Group III-V second semiconductor layer131should be all depleted, the first conductive Group III-V second semiconductor layer133and the second conductive Group III-V second semiconductor layer131should have the same width (Wn=Wp inFIG. 1) and should also have the same concentration.

As shown inFIG. 1, the second electrode143and the third electrode145may be formed in a horizontal direction of the first electrode141, respectively.

That is, the first electrode141, the second electrode143, and the third electrode145are disposed at different heights, but are formed in a horizontal direction.

FIG. 2is a view for illustrating a specific example of the semiconductor device ofFIG. 1.

As shown inFIG. 2, the semiconductor device200may include: an undoped GaN layer210; a first conductive AlGaN layer220formed on the undoped GaN layer210; a source electrode241formed on one side of the first conductive AlGaN layer220; first and second conductive AlGaN layers233and231formed on the other side of the first conductive AlGaN layer220and formed in a direction perpendicular to the source electrode241; a gate electrode243formed on one side of the first and second conductive AlGaN layers233and231; and a drain electrode245formed on the other side of the first and second conductive AlGaN layers233and231.

Here, the first conductive AlGaN layer may be N-type, and the second conductive AlGaN layer may be P-type.

As a thickness of the first conductive (N-type) AlGaN layer220is thin,2Dimensional Electron Gas (2DEG) is decreased on an interface between the undoped AlGaN layer210and the first conductive (N-type) AlGaN layer220, and as a thickness thereof is large, a large amount of electron carrier may be secured on the interface between the undoped AlGaN layer210and the first conductive (N-type) AlGaN layer220. Therefore, the thickness of the first conductive (N-type) AlGaN layer220may be determined in consideration of the above-description.

As shown inFIG. 2, the gate electrode243and the drain electrode245may be formed in a horizontal direction of the source electrode241, respectively.

That is, the source electrode241, the gate electrode243, and the drain electrode245are disposed at different heights, but are formed in a horizontal direction.

In addition, the first conductive AlGaN layer233and the second conductive AlGaN layer231may be alternately formed.

In addition, as shown inFIG. 2, the number of first conductive AlGaN layer233and the number of second conductive AlGaN layer231may be in plural, respectively.

In this case, as shown inFIG. 2, the first conductive AlGaN layer233and the second conductive AlGaN layer231may be sequentially and alternately formed, respectively. For example, the semiconductor device200has a structure obtained by forming the second conductive AlGaN layer231, then forming the first conductive AlGaN layer233so as to be contacted to the second conductive AlGaN layer231, and repeating these formations.

In addition, as shown inFIG. 2, a width of the first conductive AlGaN layer233and a width of the second conductive AlGaN layer231in a direction of the source electrode241may be the same.

For example, the width (Wn) of the first conductive AlGaN layer233and the width (Wp) of the second conductive AlGaN layer231shown inFIG. 2are the same.

Here, the term ‘same’ does not mean thickness of dimensions that are accurately the same in to mathematics, but means the thickness of dimensions that are substantially the same in consideration of errors in design, in manufacture, in measurement, or the like.

In addition, the first conductive AlGaN layer233and the second conductive AlGaN layer231may have the same concentration.

That is, at the time of reverse bias, since a stripe structure (alternate structure) of the first conductive AlGaN layer233and the second conductive AlGaN layer231should be all depleted, the first conductive AlGaN layer233and the second conductive AlGaN layer231should have the same width (Wn=Wp inFIG. 2) and should also have the same concentration.

A general AlGaN/GaN field effect transistor (hereinafter, referred to as FET) has a structure in which there are a source terminal and a drain terminal forming an ohmic contact with an AlGaN layer and a gate contact is formed on the AlGaN layer to form a Schottky contact.

Accordingly, an operation of the FET is performed by controlling the voltage of the gate terminal to connect or disconnect 2DEG between the source terminal and the drain terminal.

In the above-described case, the source terminal and the drain terminal need to be spaced apart at a predetermined distance or larger for securing breakdown voltage, and the reason is that the longer the spaced distance, the larger the resistance between the source terminal and the drain terminal. Meanwhile, in order to decrease the resistance between the source terminal and the drain terminal, the spaced distance therebetween is required to be decreased; however, in this case, it is difficult to secure the breakdown voltage.

In the preferred embodiment of the present invention, the P-type AlGaN layers and the N-type AlGaN layers are alternately formed (hereinafter, referred to as a P/N AlGaN stripe structure), and the gate electrode and the drain electrode forming an ohmic contact with the gate electrode may be formed on the stripe structure.

In the above-described structure, the gate electrode may form a Schottky contact with P-type AlGaN layer and N-type AlGaN layer, to thereby be still operated as a gate.

In addition, since the semiconductor device of the present invention is formed so that the P/N type AlGaN stripe structure has the same concentration as each other, at the time of applying high voltage to the drain electrode, the entire area of the P/N AlGaN stripe structure is depleted to be converted into a pseudo intrinsic AlGaN state. Therefore, when considering that as concentration of a substrate decreases, breakdown capacity generally increases, even though the spaced distance between the gate electrode and the drain electrode is short, the structure of the semiconductor device of the present invention may secure high breakdown voltage.

In addition, in the semiconductor device of the present invention, as the spaced distance between the gate electrode and the drain electrode is short, the spaced distance between the source electrode and the drain electrode is also decreased to lower a turn-on voltage.

That is, at the time of operating the semiconductor device of the present invention in an electrical conduction, the spaced distance between the source electrode and the drain electrode is relatively short as compared to the case of the prior art, such that the turn-on voltage may be lowered.

At the time of operating the semiconductor device in a blocking mode, the P/N AlGaN stripe structure disposed between the gate electrode and the drain electrode is entirely depleted to be converted into the intrinsic AlGaN state, such that the same breakdown voltage as the case of the prior art may be achieved even though the spaced distance between the drain electrode and the source electrode is relatively short.

As set forth above, with the semiconductor device according to the preferred embodiment of the present invention, the P-type Group III-V semiconductor layer and the N-type Group III-V semiconductor layer are alternately formed on the Group III-V semiconductor layer such as AlGaN, to and the gate electrode and the drain electrode forming the ohmic contact with the gate electrode are then formed on the P-type and N-type Group III-V semiconductor layers, thereby making it possible to secure the high breakdown voltage at the time of operating the semiconductor device.

In addition, with the semiconductor device according to the preferred embodiment of the present invention, the spaced distance between the source electrode and the drain electrode shorter than that of the prior art is secured at the same breakdown voltage level to thereby lower the turn-on voltage of the semiconductor device, thereby making it possible to implement the semiconductor device having a size smaller than that of the prior art.