Manufacturing method of semiconductor device

Abstract

The transistor characteristics of a MIS transistor provided with a gate insulating film formed to contain oxide with a relative dielectric constant higher than that of silicon oxide are improved. After a high dielectric layer made of hafnium oxide is formed on a main surface of a semiconductor substrate, the main surface of the semiconductor substrate is heat-treated in a non-oxidation atmosphere. Next, an oxygen supplying layer made of hafnium oxide deposited by ALD and having a thickness smaller than that of the high dielectric layer is formed on the high dielectric layer, and a cap layer made of tantalum nitride is formed. Thereafter, the main surface of the semiconductor substrate is heat-treated.

1 . A manufacturing method of a semiconductor device comprising the steps of: forming a gate insulating film of a MIS transistor on a semiconductor substrate; and forming a gate electrode of the MIS transistor on the gate insulating film,
 wherein the step of forming the gate insulating film on the semiconductor substrate comprises the steps of:   (a) forming a first layer made of oxide with a relative dielectric constant higher than that of silicon oxide on a main surface of the semiconductor substrate;   (b) after the step (a), heat-treating the main surface of the semiconductor substrate in a non-oxidation atmosphere;   (c) forming, on the first layer, a second layer made of oxide having an oxygen proportion higher than that in the first layer just after the step (b);   (d) forming, on the second layer, a cap layer made of metal suppressing diffusion of oxygen; and   (e) after the step (d), heat-treating the main surface of the semiconductor substrate.   
   
   
       2 . The manufacturing method of a semiconductor device according to  claim 1 ,
 wherein, in the step (c), a hafnium oxide film forming the second layer is formed on the first layer by ALD using water as an oxygen material.   
   
   
       3 . The manufacturing method of a semiconductor device according to  claim 1 ,
 wherein, in the step (c), an aluminum oxide film forming the second layer is formed on the first layer by ALD using water as an oxygen material.   
   
   
       4 . The manufacturing method of a semiconductor device according to  claim 1 ,
 wherein, in the step (c), a tantalum oxide film forming the second layer is formed on the first layer by ALD using water as an oxygen material.   
   
   
       5 . The manufacturing method of a semiconductor device according to  claim 1 , further comprising the step of:
 (f) forming the gate electrode made of the cap layer by patterning the cap layer.   
   
   
       6 . The manufacturing method of a semiconductor device according to  claim 1 ,
 wherein, in the step (b), the first layer is densified.   
   
   
       7 . The manufacturing method of a semiconductor device according to  claim 1 ,
 wherein, in the step (e), oxygen is supplied from the second layer to the first layer.