Method of manufacturing p-type nitride semiconductor and semiconductor device fabricated by the method

Abstract

The present invention includes a first step of forming a nitride semiconductor layer by metal organic chemical vapor deposition by using a first carrier gas containing a nitrogen carrier gas and a hydrogen carrier gas of a flow quantity larger than that of the nitrogen carrier gas to thereby supply a raw material containing Mg and a Group V raw material containing N, and a second step of lowering a temperature by using a second carrier gas to which a material containing N is added, and hence solves the problems encountered in the art.

1 . A method of manufacturing a p-type nitride semiconductor, comprising:
 a first step of forming a nitride semiconductor layer by metal organic chemical vapor deposition by using a first carrier gas containing a nitrogen gas and a hydrogen gas of a flow quantity larger than a flow quantity of said nitrogen gas to thereby supply a raw material containing magnesium and a Group V raw material containing nitrogen (N); and   a second step of lowering a temperature of the first step by using a second carrier gas to which a material containing nitrogen (N) is added at a concentration of at least 0.01% and less than 20%.   
     
     
         2 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein ammonia is used at a concentration of at least 0.01% and at most 5% as said material containing nitrogen (N). 
     
     
         3 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein in said first carrier gas, a ratio of the hydrogen gas with respect to a total flow quantity of the nitrogen gas and the hydrogen gas is more than 70% and at most 95%. 
     
     
         4 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein a total layer thickness of said nitride semiconductor layer is at least 0.5 μm. 
     
     
         5 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein said nitride semiconductor layer is made of a plurality of layers, and a total layer thickness of a layer including a nitride semiconductor with an aluminum composition ratio of at least 2% is at least 0.3 μm. 
     
     
         6 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein said raw material containing magnesium is bis (ethyl cyclopentadienyl) magnesium. 
     
     
         7 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein a flow quantity of said Group V raw material containing nitrogen (N) is smaller than the flow quantity of the hydrogen gas in the first carrier gas. 
     
     
         8 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein a flow quantity of the second carrier gas is larger than the flow quantity of the nitrogen gas in the first carrier gas. 
     
     
         9 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein the second carrier gas is argon or nitrogen. 
     
     
         10 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein said second step is a step of lowering the temperature to 400° C. or lower, and a time required for reaching 400° C. is at most 25 minutes. 
     
     
         11 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , wherein dimethyl hydrazine is used at a concentration of at least 0.01% and at most 2% as said material containing nitrogen (N). 
     
     
         12 . The method of manufacturing the p-type nitride semiconductor according to  claim 1 , further comprising:
 a third step of subjecting the nitride semiconductor layer to an annealing treatment after said second step in an inert gas for at least one minute and at most 15 minutes.   
     
     
         13 . The method of manufacturing the p-type nitride semiconductor according to  claim 12 , wherein the annealing treatment in the third step is performed at a temperature of at least 700° C. and at most 900° C. 
     
     
         14 . The method of manufacturing the p-type nitride semiconductor according to  claim 12 , wherein in said third step, ammonia is further added at a concentration of at least 0.01% and at a most 5% in addition to said inert gas. 
     
     
         15 . The method of manufacturing the p-type nitride semiconductor according to  claim 12 , wherein in said third step, hydrogen is further added at a concentration of at least 10 ppm and at most 500 ppm in addition to said inert gas. 
     
     
         16 . A semiconductor device including a p-type nitride semiconductor layer fabricated by the manufacturing method recited in  claim 1 .