Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device includes a first semiconductor layer formed over a substrate, a second semiconductor layer formed over the first semiconductor layer, a source electrode and a drain electrode formed over the second semiconductor layer, an insulating film formed over the second semiconductor layer, a gate electrode formed over the insulating film, and a protection film covering the insulating film, the protection film being formed by thermal CVD, thermal ALD, or vacuum vapor deposition.

1 . A semiconductor device comprising:
 a first semiconductor layer formed over a substrate;   a second semiconductor layer formed over the first semiconductor layer;   a source electrode and a drain electrode formed over the second semiconductor layer;   an insulating film formed over the second semiconductor layer;   a gate electrode formed over the insulating film; and   a protection film covering the insulating film, the protection film being formed by thermal CVD, thermal ALD, or vacuum vapor deposition.   
     
     
         2 . A semiconductor device comprising:
 a first semiconductor layer formed over a substrate;   a second semiconductor layer formed over the first semiconductor layer;   a source electrode and a drain electrode formed over the second semiconductor layer;   a recess formed in the second semiconductor layer, or in the second semiconductor layer and a portion of the first semiconductor layer;   an insulating film formed over the second semiconductor layer and in the recess;   a gate electrode formed on the insulating film inside the recess; and   a protection film covering the insulating film, the protection film being formed by thermal CVD, thermal ALD, or vacuum vapor deposition.   
     
     
         3 . The semiconductor device according to  claim 1 , wherein the protection film is a metal oxide film. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the protection film contains one or more materials selected from silicon oxide, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, yttrium oxide, lanthanum oxide, tantalum oxide, silicon nitride, aluminum nitride, and silicon oxynitride. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the protection film is a multilayer protection film. 
     
     
         6 . The semiconductor device according to  claim 1 , wherein the insulating film is a metal oxide film. 
     
     
         7 . The semiconductor device according to  claim 1 , wherein the insulating film contains one or more materials selected from silicon oxide, aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, yttrium oxide, lanthanum oxide, tantalum oxide, silicon nitride, aluminum nitride, and silicon oxynitride. 
     
     
         8 . The semiconductor device according to  claim 1 , wherein the insulating film is formed by plasma CVD, plasma ALD, or sputtering. 
     
     
         9 . The semiconductor device according to  claim 1 , wherein the protection film and the insulating film contain a same material. 
     
     
         10 . The semiconductor device according to  claim 1 , further comprising:
 a third semiconductor layer positioned between the second semiconductor layer and the insulating film.   
     
     
         11 . A semiconductor device manufacturing method comprising:
 forming a first semiconductor layer and a second semiconductor layer in this order over a substrate;   forming a source electrode and a drain electrode over the second semiconductor layer;   forming an insulating film over the second semiconductor layer;   forming a gate electrode over the insulating film, and   forming a protection film by thermal CVD, thermal ALD, or vacuum vapor deposition so as to cover the insulating film.   
     
     
         12 . A semiconductor device manufacturing method comprising:
 forming a first semiconductor layer and a second semiconductor layer in this order over a substrate;   forming a source electrode and a drain electrode over the second semiconductor layer;   forming a recess in the second semiconductor layer;   forming an insulating film over the second semiconductor layer and in the recess;   forming a gate electrode on the insulating film inside the recess; and   forming a protection film by thermal CVD, thermal ALD, or vacuum vapor deposition so as to cover the insulating film.   
     
     
         13 . The semiconductor device manufacturing method according to  claim 11 , wherein the forming the protection film includes:
 forming an aluminum oxide film by thermal ALD by alternately supplying trimethylaluminum and water.   
     
     
         14 . The semiconductor device manufacturing method according to  claim 11 , wherein the forming the protection film includes:
 forming a metal oxide film with a thickness ranging from 10 nm to 50 nm;   performing a thermal process on the metal oxide film at a temperature ranging from 500° C. to 800° C.; and   repeating the formation of the metal oxide film and the thermal process.   
     
     
         15 . The semiconductor device manufacturing method according to  claim 12 , wherein the forming the protection film includes:
 forming an aluminum oxide film by thermal ALD by alternately supplying trimethylaluminum and water.   
     
     
         16 . The semiconductor device manufacturing method according to  claim 12 , wherein the forming the protection film includes:
 forming a metal oxide film with a thickness ranging from 10 nm to 50 nm;   performing a thermal process on the metal oxide film at a temperature ranging from 500° C. to 800° C.; and   repeating the formation of the metal oxide film and the thermal process.