Nitride semiconductor element and nitride semiconductor package

Abstract

A nitride semiconductor element capable of accommodating GaN electron transfer layers of a wide range of thickness, so as to allow greater freedom of device design, and a nitride semiconductor element package with excellent voltage tolerance performance and reliability. On a substrate, a buffer layer including an AlN layer, a first AlGaN layer and a second AlGaN layer is formed. On the buffer layer, an element action layer including a GaN electron transfer layer and an AlGaN electron supply layer is formed. Thus, an HEMT element is constituted.

What is claimed is: 
     
         1 . A nitride semiconductor element, comprising:
 a Si substrate including a primary surface;   a buffer layer comprised of an AlGaN laminated structure;   a Group III-nitride electron transfer layer formed on the AlGaN laminated structure; and   a Group III-nitride electron supply layer formed on the Group III-nitride electron transfer layer,   wherein the AlGaN laminated structure has an average lattice constant in the horizontal direction, the average lattice constant of the AlGaN laminated structure being lower than an original average lattice constant of an original AlGaN layer.   
     
     
         2 . The nitride semiconductor element of  claim 1 , wherein the AlGaN laminated structure is applied by a compression stress in the horizontal direction. 
     
     
         3 . The nitride semiconductor element of  claim 1 , wherein the AlGaN laminated structure comprises:
 a first AlGaN layer; and   a second AlGaN layer has an Al component that is lower than an Al component of the first AlGaN layer, wherein the first AlGaN layer is closer to an AlN layer formed on the primary surface of the Si substrate than the second AlGaN layer.   
     
     
         4 . The nitride semiconductor element according to  claim 3 , wherein the first AlGaN layer and the second AlGaN layer are compressed in the horizontal direction. 
     
     
         5 . The nitride semiconductor element according to  claim 3 , wherein the difference in the Al component between the original AlGaN layer and the first AlGaN layer arranged in contact with the surface of the original AlGaN layer is 10% or more. 
     
     
         6 . The nitride semiconductor element according to  claim 3 , wherein the Al component of the first AlGaN layer is 50% and the Al component of the original AlGaN layer is 10%. 
     
     
         7 . The nitride semiconductor element according to  claim 3 , wherein the Al component of the first AlGaN layer is 50% and the Al component of the original AlGaN layer is 17%. 
     
     
         8 . The nitride semiconductor element according to  claim 3 , wherein the Al component of the first AlGaN layer is 50% and the Al component of the original AlGaN layer is 20%. 
     
     
         9 . The nitride semiconductor element according to  claim 3 , wherein the Al component of the first AlGaN layer is 50% and the Al component of the original AlGaN layer is 25%. 
     
     
         10 . The nitride semiconductor element according to  claim 3 , wherein the AlN layer has a first horizontal average lattice constant, the Group III-nitride electron transfer layer has a second horizontal average lattice constant, and the original average lattice constant of the original AlGaN layer and the horizontal in-plane lattice constant of the first AlGaN layer are greater than the first horizontal average lattice constant and smaller than the second horizontal average lattice constant. 
     
     
         11 . The nitride semiconductor element according to  claim 10 , wherein the first horizontal average lattice constant, the horizontal in-plane lattice constant of the first AlGaN layer, the original average lattice constant of the original AlGaN layer, and the second horizontal average lattice constant are monotonic increasing values. 
     
     
         12 . The nitride semiconductor element according to  claim 1 , wherein the original AlGaN layer is arranged to compress the Group III nitride electron transfer layer in the horizontal direction. 
     
     
         13 . The nitride semiconductor element according to  claim 1 , wherein the first AlGaN layer is arranged to compress the original AlGaN layer in the horizontal direction. 
     
     
         14 . The nitride semiconductor element according to  claim 3 , wherein the AlN layer is stretched by the first AlGaN layer in the horizontal direction. 
     
     
         15 . The nitride semiconductor element according to  claim 1 , wherein the primary surface of the Si substrate is a (111) plane. 
     
     
         16 . The nitride semiconductor element according to  claim 1 , wherein the Group III-nitride electron transfer layer has a thickness of 500 nm to 2000 nm. 
     
     
         17 . The nitride semiconductor element according to  claim 1 , wherein the Group III-nitride electron supply layer has a thickness of 500 nm to 2000 nm. 
     
     
         18 . The nitride semiconductor element according to  claim 3 , wherein the AlN layer has a thickness of 50 nm to 200 nm. 
     
     
         19 . The nitride semiconductor element according to  claim 1 , wherein the first AlGaN layer has a thickness of 100 nm to 500 nm. 
     
     
         20 . The nitride semiconductor element according to  claim 1 , wherein the original AlGaN layer has a thickness of 100 nm to 500 nm.