Nitride-based semiconductor device and method of manufacturing the same

Abstract

The nitride-based semiconductor device includes a carrier traveling layer 1 composed of non-doped AlxGa1-xN (0≦X<1); a barrier layer 2 formed on the carrier traveling layer 1 and composed of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y) having a lattice constant smaller than that of the carrier traveling layer 1; a threshold voltage control layer 3 formed on the barrier layer 2 and composed of a non-doped semiconductor having a lattice constant equal to that of the carrier traveling layer 1; and a carrier inducing layer 4 formed on the threshold voltage control layer 3 and composed of a non-doped or n-type semiconductor having a lattice constant smaller than that of the carrier traveling layer 1. The nitride-based semiconductor device further includes a gate electrode 5 formed in a recess structure, a source electrode 6 and a drain electrode 7.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-252657, filed on Aug. 31, 2005; the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a semiconductor device, and more particularly to a nitride-based semiconductor device and a method of manufacturing the same. [0004] 2. Description of the Related Art [0005] It is effective to use a material having high critical electric field to a power semiconductor device such as a switching device or high frequency power semiconductor device, so that a nitride-based semiconductor material having high critical electric field intensity is used. [0006] As a nitride-based semiconductor device using a conventional nitride-based semiconductor material, a first conventional art has been known in which a carrier traveling layer ...

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Benefits of technology

[0020] According to one aspect of the present invention, a nitride-based semiconductor device includes a carrier traveling layer made of non-doped AlxGa1-xN (0≦X<1); a barrier layer formed on the carrier traveling layer and made of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y) having a lattice constant smaller than that of the carrier traveling layer; a threshold voltage control layer formed on the barrier layer and made of a non-doped semiconductor having a lattice constant equal to that of the carrier traveling layer; a carrier inducing layer formed on the threshold voltage control layer and made of a non-doped or n-type semiconductor having a lattice constant smaller than that of the carrier traveling layer; a gate electrode formed in a recess structure that is formed at a predetermined position of the carrier inducing layer and a bottom of which reaches to the threshold voltage control layer; and a source electrode and a drain electrode formed at any one of the barrier layer, the threshold voltage control layer and the carrier inducing layer across the gate electrode.

[0021] According to another aspect of the present invention, a nitride-based semiconductor device includes a first nitride-based semiconductor layer made of non-doped AlxGa1-xN (0≦X<1); a second nitride-based semiconductor layer formed on the first nitride-based semiconductor layer and made of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y) having a lattice constant smaller than that of the first nitride-based semiconductor layer; a first semiconductor layer formed on the second nitride-based semiconductor layer and made of a non-doped semiconductor having a lattice constant equal to that of the first nitride-based semiconductor layer; a second semiconductor layer formed on the first semiconductor layer and made of a non-doped or n-type semiconductor having a lattice constant smaller than that of the first nitride-based semiconductor layer; a gate electrode formed in a recess structure that is formed at a predetermined position of the second semiconductor layer and a bottom of which reaches to the first semiconductor layer; a source electrode and a drain electrode formed at any one of the second nitride-based semiconductor layer, and the first and second semiconductor layers across the gate electrode.

[0022] According to still another aspect of the present invention, a method of manufacturing a nitride-based semiconductor device includes forming a carrier traveling layer made of non-doped AlxGa1-xN (0≦X<1) on a substrate; forming a barrier layer on the carrier traveling layer, the barrier layer being made of non-doped or n-type AlYGa1-YN (0<Y≦1, X<Y) having a lattice constant smaller than that of the carrier traveling layer; forming a threshold voltage control layer on the barrier layer, the threshold voltage control layer being made of a non-doped semiconductor having a lattice constant equal to that of the carrier traveling layer; forming a carrier inducing layer on the threshold voltage control layer, the carrier inducing layer being made of a non-doped or n-type semiconductor having a lattice constant smaller than that of the carrier traveling layer; forming a recess structure by removing a predetermined position of the carrier inducing layer and the threshold voltage control layer so as to expose the threshold voltage control layer; forming a source electrode and a drain electrode on any one of the barrier layer, the threshold voltage control layer and the carrier inducing layer across the recess structure by using a mask on the recess structure; and forming a gate electrode in the recess structure.

[0023] According to still another aspect of the present invention, a method of manufacturing a nitride-based semiconductor device includes forming a first nitride-based semiconductor layer made of non-doped AlxGa1-xN (0≦X<1) on a substrate; forming a second nitride-based semiconductor layer on the first nitride-based semiconductor layer, the second nitride-based semiconductor layer being made of non-doped or n-type AlYGa1-YN ((0<Y≦1, X<Y) having a lattice constant smaller than that of the first nitride-based semiconductor layer; forming a first semiconductor layer on the second nitride-based semiconductor layer, the first semiconductor layer being made of a non-doped semiconductor having a lattice constant equal to that of the first nitride-based semiconductor layer; forming a second semiconductor layer on the first semiconductor layer, the second semiconductor layer being made of a non-doped or n-type semiconductor having a lattice constant smaller than that of the first nitride-based semiconductor layer; forming a recess structure by removing a predetermined position of the second and the first semiconductor layers so as to expose the first semiconductor layer; forming a source electrode and a drain electrode on any one of the second nitride-based semiconductor layer and the first and second semiconductor layers across the recess structure by using a mask on the recess structure; and forming a gate electrode in the recess structure.

Problems solved by technology

Therefore, when the Al composition ratio in the barrier layer is greater than the Al composition ratio in the carrier traveling layer, the lattice constant of the barrier layer becomes small compared to the carrier traveling layer, so that a distortion is produced on the barrier layer.

Specifically, it is difficult to fabricate, with good yield, the normally off-type nitride-based semiconductor device having reduced on-resistance in the nitride-based semiconductor device disclosed in the first conventional art.

However, there arises a problem that it is difficult to fabricate a normally off-type semiconductor device with good yield in view of the processing precision.

Accordingly, there arise a problem that it is difficult to fabricate a semiconductor device by controlling the threshold voltage with good yield.

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