Semiconductor wafer, semiconductor device and method of fabricating the same

Abstract

A semiconductor substrate according to an embodiment includes: a first semiconductor wafer having a first crystal; and a second semiconductor wafer formed of a second crystal substantially same as the first crystal on the first semiconductor wafer, a crystal-axis direction of unit cell thereof being twisted at a predetermined angle around a direction vertical to a principal surface of the second semiconductor wafer from that of the first semiconductor wafer.

1 - 9 . (canceled) 
     
     
         10 . A method of fabricating a semiconductor device, comprising:
 laminating a second substrate, of which plane direction of the principal surface is same as that of a first substrate, on the first substrate in the state that the crystal-axis directions in the principal surfaces of the first and second substrates are at a predetermined angle around a direction vertical to the principal surface to each other,   forming first and second fins by patterning the second substrate,   selectively amorphizing the first fin; and   substantially matching the crystal-axis direction of the unit cell of the first fin to that of the first substrate by recrystallizing the amorphized first fin using the first substrate as a base.   
     
     
         11 . The method of fabricating a semiconductor device according to  claim 10 , wherein the plane directions of the principal surface of the first and second substrates are {100}; and
 the predetermined angle is (45+90×n)° (n is an integer number).   
     
     
         12 . The method of fabricating a semiconductor device according to  claim 10 , wherein the first and second substrates are laminated by forming hydrophilic bonding or hydrophobic bonding between the first and second substrates. 
     
     
         13 . The method of fabricating a semiconductor device according to  claim 10 , wherein the first and second substrates have notches or an orientation flats provided in the crystal-axis directions at a predetermined angle to each other; and
 the first substrate and the second substrate are laminated by aligning the positions of the respective notches or orientation flats.   
     
     
         14 . The method of fabricating a semiconductor device according to  claim 10 , wherein the first and second substrates have notches or orientation flats provided in the same crystal-axis direction; and
 the first substrate and the second substrate are laminated with rotating a position of the respective notches or orientation flats at a predetermined angle to each other.   
     
     
         15 . The method of fabricating a semiconductor device according to  claim 10 , wherein the first fin is selectively amorphized by implanting impurity ions which do not function as a conductivity type impurity. 
     
     
         16 . The method of fabricating a semiconductor device according to  claim 10 , wherein source/drain regions of different conductivity types are formed on the first and second fins after recrystallizing the first fin. 
     
     
         17 . The method of fabricating a semiconductor device according to  claim 10 , wherein an oxide film is formed on an interface of the first and second substrates when laminating the first and second substrates; and
 the oxide film between the first fin and the first substrate is destroyed and a region in which the oxide film has been destroyed is recrystallized by amorphizing and recrystallizing the first fin.   
     
     
         18 . The method of fabricating a semiconductor device according to  claim 10 , wherein n-type and p-type source/drain regions are formed in the first and second fins, respectively after recrystallizing the first fin. 
     
     
         19 . The method of fabricating a semiconductor device according to  claim 10 , wherein the first fin is amorphized after forming a device isolation region so as to cover side faces of the first and second fins. 
     
     
         20 . The method of fabricating a semiconductor device according to  claim 10 , wherein gate electrodes are formed via gate insulating films so as to sandwich both side faces of the first and second fins, respectively after recrystallizing the first fin, then, first and second transistors are formed; and
 first and second strain generating films for generating a strain in channel regions of the first and second transistors, respectively, are formed on the first and second transistors.