III-Nitride Device Having a Buried Insulating Region

Abstract

A semiconductor device includes a compound semiconductor material on a semiconductor substrate, the compound semiconductor material having a channel region, a source region, a drain region spaced apart from the source region, the channel region extending between the source region and the drain region, and an insulating region positioned under the channel region in an active region of the semiconductor device so that the insulating region is separated from the channel region by a portion of the compound semiconductor material in the active region. The active region includes the source, the drain and the channel region. The insulating region is discontinuous over a length of the channel region between the source region and the drain region

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a compound semiconductor material on a semiconductor substrate, the compound semiconductor material having a channel region;   a source region;   a drain region spaced apart from the source region, the channel region extending between the source region and the drain region; and   an insulating region positioned under the channel region in an active region of the semiconductor device so that the insulating region is separated from the channel region by a portion of the compound semiconductor material in the active region, the active region including the source, the drain and the channel region, the insulating region being discontinuous over a length of the channel region between the source region and the drain region.   
     
     
         2 . The semiconductor device of  claim 1 , wherein the insulating region comprises a hollow cavity lined with an insulating material. 
     
     
         3 . The semiconductor device of  claim 2 , wherein the hollow cavity is formed partly in the compound semiconductor material and partly in the semiconductor substrate. 
     
     
         4 . The semiconductor device of  claim 2 , wherein the hollow cavity is formed entirely in the semiconductor substrate below the compound semiconductor material. 
     
     
         5 . The semiconductor device of  claim 2 , wherein the hollow cavity is filled with a gas. 
     
     
         6 . The semiconductor device of  claim 1 , wherein the insulating region comprises a cavity filled with an insulating material. 
     
     
         7 . The semiconductor device of  claim 6 , wherein the cavity is formed partly in the compound semiconductor material and partly in the semiconductor substrate. 
     
     
         8 . The semiconductor device of  claim 6 , wherein the cavity is formed entirely in the semiconductor substrate below the compound semiconductor material. 
     
     
         9 . The semiconductor device of  claim 1 , wherein the compound semiconductor material comprises a GaN alloy layer on a GaN layer, the channel region is a two-dimensional electron gas disposed in the GaN layer near an interface with the GaN alloy layer, and the insulating region is disposed below the GaN alloy layer and the two-dimensional electron gas. 
     
     
         10 . The semiconductor device of  claim 1 , further comprising:
 a trench extending from a main surface of the compound semiconductor material to the insulating region in a region outside the active region; and   an insulating material disposed in the trench.   
     
     
         11 . The semiconductor device of  claim 10 , wherein the trench extends perpendicular to the source region and the drain region over a length of the insulating region. 
     
     
         12 . The semiconductor device of  claim 1 , further comprising a conductive plug extending from the drain or source region, through the compound semiconductor material to a side of the semiconductor substrate facing away from the compound semiconductor material. 
     
     
         13 . A semiconductor device, comprising:
 a semiconductor substrate;   a compound semiconductor epitaxial material on the semiconductor substrate, the compound semiconductor epitaxial material having a channel region and a higher energy band gap than the semiconductor substrate;   a first doped region extending to the compound semiconductor epitaxial material;   a second doped region extending to the compound semiconductor epitaxial material and spaced apart from the first doped region by the channel region; and   an insulating region positioned under the channel region in an active region of the semiconductor device so that the insulating region is separated from the channel region by a portion of the compound semiconductor epitaxial material in the active region, the insulating region being discontinuous over a length of the channel region between the first and second doped regions.   
     
     
         14 . The semiconductor device of  claim 13 , wherein the insulating region comprises a hollow cavity lined with an insulating material. 
     
     
         15 . The semiconductor device of  claim 14 , wherein the hollow cavity is formed partly in the compound semiconductor epitaxial material and partly in the semiconductor substrate. 
     
     
         16 . The semiconductor device of  claim 14 , wherein the hollow cavity is formed entirely in the semiconductor substrate below the compound semiconductor epitaxial material. 
     
     
         17 . The semiconductor device of  claim 14 , wherein the hollow cavity is filled with a gas. 
     
     
         18 . The semiconductor device of  claim 13 , wherein the insulating region comprises a cavity filled with an insulating material. 
     
     
         19 . The semiconductor device of  claim 18 , wherein the cavity is formed partly in the compound semiconductor epitaxial material and partly in the semiconductor substrate. 
     
     
         20 . The semiconductor device of  claim 18 , wherein the cavity is formed entirely in the semiconductor substrate below the compound semiconductor epitaxial material.