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 Al x Ga 1-x N (0≦X<1); a barrier layer 2 formed on the carrier traveling layer 1 and composed of non-doped or n-type Al Y Ga 1-Y N (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.

1 . A nitride-based semiconductor device comprising: 
 a carrier traveling layer made of non-doped Al x Ga 1-x N (0≦X<1);    a barrier layer formed on the carrier traveling layer and made of non-doped or n-type Al Y Ga 1-Y N (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.    
   
   
       2 . The nitride-based semiconductor device according to  claim 1 , wherein the thickness of the barrier layer is not more than 16.4×(1−1.27×(Y−X))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       3 . The nitride-based semiconductor device according to  claim 1 , wherein the total thickness of the barrier layer and the carrier inducing layer is not less than 16.4×(1−1.27×(Y−x))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       4 . The nitride-based semiconductor device according to  claim 2 , wherein the total thickness of the barrier layer and the carrier inducing layer is not less than 16.4×(1−1.27×(Y−X))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       5 . The nitride-based semiconductor device according to  claim 1  further comprising: 
 an insulating film formed so as to cover the gate electrode, source electrode and drain electrode; and    a field plate electrode formed such that at least one end portion thereof is positioned on the insulating film between the end portion of the gate electrode at the side of the drain electrode and the drain electrode, and connected to the gate electrode or the source electrode.    
   
   
       6 . A nitride-based semiconductor device comprising: 
 a first nitride-based semiconductor layer made of non-doped Al x Ga 1-x N (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 Al Y Ga 1-Y N (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.    
   
   
       7 . The nitride-based semiconductor device according to  claim 6 , wherein the thickness of the second nitride-based semiconductor layer is not more than 16.4×(1−1.27×(Y−X))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       8 . The nitride-based semiconductor device according to  claim 6 , wherein the total thickness of the second nitride-based semiconductor layer and the second semiconductor layer is not less than 16.4×(1−1.27×(Y−X))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       9 . The nitride-based semiconductor device according to  claim 7 , wherein the total thickness of the second nitride-based semiconductor layer and the second semiconductor layer is not less than 16.4×(1−1.27×(Y−X))/(Y−X) [Å], wherein Y−X<1/1.27.  
   
   
       10 . The nitride-based semiconductor device according to  claim 6  further comprising: 
 an insulating film formed so as to cover the gate electrode, source electrode and drain electrode; and    a field plate electrode formed such that at least one end portion thereof is positioned on the insulating film between the end portion of the gate electrode at the side of the drain electrode and the drain electrode, and connected to the gate electrode or the source electrode.    
   
   
       11 . A method of manufacturing a nitride-based semiconductor device comprising: 
 forming a carrier traveling layer made of non-doped Al x Ga 1-x N (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 Al Y Ga 1-Y N (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.    
   
   
       12 . The method of manufacturing a nitride-based semiconductor device according to  claim 11 , wherein, in forming the recess structure, the threshold voltage control layer is removed so that a bottom portion of the recess structure is situated between an upper surface of the threshold voltage control layer and an upper surface of the barrier layer at the predetermined position.  
   
   
       13 . A method of manufacturing a nitride-based semiconductor device comprising: 
 forming a first nitride-based semiconductor layer made of non-doped Al x Ga 1-x N (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 Al Y Ga 1-Y N (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.    
   
   
       14 . The method of manufacturing a nitride-based semiconductor device according to  claim 13 , wherein, in forming the recess structure, the threshold voltage control layer is removed so that a bottom portion of the recess structure is situated between an upper surface of the first semiconductor layer and an upper surface of the second nitride-based semiconductor layer at the predetermined position.