GALLIUM NITRIDE BASED SEMICONDUCTOR DEVICES AND METHODS OF MANUFACTURING THE SAME
Gallium nitride (GaN) based semiconductor devices and methods of manufacturing the same. The GaN-based semiconductor device may include a conductive heat dissipation substrate (that is, a thermal conductive substrate); an GaN-based multi-layer arranged on the heat dissipation substrate; and a Schottky electrode arranged on the GaN-based multi-layer. While such a GaN-based semiconductor device is being manufactured, a wafer bonding process and a laser lift-off process may be used.
1 . A gallium nitride (GaN) based semiconductor device comprising:
a conductive substrate;
an AlGaN layer arranged on the conductive substrate;
a GaN layer arranged on the AlGaN layer; and
an electrode layer arranged on the GaN layer, the electrode layer forms a Schottky contact with the GaN layer.
2 . The GaN-based semiconductor device of claim 1 , wherein the substrate comprises a material having higher thermal conductivity than a sapphire substrate.
3 . The GaN-based semiconductor device of claim 1 , wherein substrate comprises at least one of Al—Si, Si, Cu, Ni, W, Al, Cr, and a combination thereof.
4 . The GaN-based semiconductor device of claim 1 , wherein the substrate and the AlGaN layer form an ohmic contact.
5 . The GaN-based semiconductor device of claim 1 , wherein the AlGaN layer is an Al x Ga 1-x N layer (here, 0<x≦0.6).
6 . The GaN-based semiconductor device of claim 1 , wherein the AlGaN layer is a layer doped with an n-type impurity.
7 . The GaN-based semiconductor device of claim 1 , wherein the GaN layer has a single layer structure or a multi layer structure.
8 . The GaN-based semiconductor device of claim 1 , wherein the GaN layer comprises at least one of an undoped GaN layer and an n-doped GaN layer.
9 . The GaN-based semiconductor device of claim 1 , wherein the GaN layer comprises a first GaN layer contacting the electrode layer and a second GaN layer arranged between the first GaN layer and the AlGaN layer,
the first GaN layer is an undoped layer or an n-doped layer, and
the second GaN layer is doped with at least one of Si and Al.
10 . The GaN-based semiconductor device of claim 1 , wherein the AlGaN layer and the GaN layer have N-face polarity.
11 . The GaN-based semiconductor device of claim 1 , further comprising a superlattice structure layer between the substrate and the electrode layer.
12 . The GaN-based semiconductor device of claim 11 , wherein the GaN layer has a multi layer structure, and
the superlattice structure layer is arranged between a plurality of layers constituting the GaN layer.
13 . The GaN-based semiconductor device of claim 1 , further comprising a blocking layer pattern arranged in the GaN layer.
14 . A method of forming a gallium nitride (GaN) based semiconductor device, the method comprising:
forming a GaN layer on a first substrate;
forming an AlGaN layer on the GaN layer;
providing a second substrate on the AlGaN layer;
removing the first substrate to expose the GaN layer; and
forming an electrode layer on the exposed portion of the GaN layer, the electrode layer forms a Schottky contact with the GaN layer.
15 . The method of claim 14 , wherein the first substrate is a sapphire substrate.
16 . The method of claim 14 , wherein the GaN layer is formed to have a single layer structure or a multi layer structure.
17 . The method of claim 14 , wherein the GaN layer comprises at least one of an undoped GaN layer and an n-doped GaN layer.
18 . The method of claim 14 , wherein the forming of the GaN layer comprises forming a first GaN layer on the first substrate; and forming a second GaN layer on the first GaN layer,
the first GaN layer is an undoped GaN layer or an n-doped GaN layer, and
the second GaN layer is doped with at least one of Si and Al.
19 . The method of claim 14 , wherein the GaN layer is formed to have a multi layer structure,
further comprising forming a superlattice structure layer between a plurality of layers constituting the GaN layer.
20 . The method of claim 14 , wherein the AlGaN layer is an Al x Ga 1-x N layer (here, 0<x≦0.6).
21 . The method of claim 14 , wherein the AlGaN layer is an n-doped layer.
22 . The method of claim 14 , wherein the second substrate is a conductive substrate.
23 . The method of claim 14 , wherein the second substrate comprises a material having higher thermal conductivity than the first substrate.
24 . The method of claim 14 , wherein the second substrate comprises at least one of Al—Si, Si, Cu, Ni, W, Al, Cr, and a combination thereof.
25 . The method of claim 14 , wherein the second substrate is arranged on the AlGaN layer by using a bonding method or a plating method.
26 . The method of claim 14 , further comprising forming an ohmic contact layer between the AlGaN layer and the second substrate.
27 . The method of claim 14 , wherein the removing of the first substrate is performed by a laser lift-off method.
28 . The method of claim 14 , further comprising:
forming a plurality of protrusions with pointed ends on the top surface of the first substrate; and
forming a blocking layer pattern corresponding to the plurality of protrusions in the GaN layer.
29 . The method of claim 14 , further comprising, after the first substrate is removed, partially removing the GaN layer.