Room temperature ferromagnetic semiconductor grown by plasma enhanced molecular beam epitaxy and ferromagnetic semiconductor based device

Abstract

A 3 group-5 group compound ferromagnetic semiconductor, comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P, wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase as a whole. The ferromagnetic semiconductor can be fabricated by a plasma-enhance molecular beam epitaxy growing method and since it shows the ferromagnetic characteristics at a room temperature, it can be applied as various spin electron devices.

What is claimed is:  
     
         1 . A 3 group-5 group compound ferromagnetic semiconductor, comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P, 
 wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase on the whole.  
 
     
     
         2 . The semiconductor of  claim 1 , wherein the ferromagnetic semiconductor has its Curie temperature above room temperature.  
     
     
         3 . A method for fabricating a ferromagnetic semiconductor comprising the steps of: 
 forming a 3 group-5 group compound semiconductor thin film comprising one material ‘A’ selected from the group consisting of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P on a substrate; and    doping one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V as a material for substituting the material ‘A’, while forming the compound semiconductor thin film by a plasma-enhanced molecular beam epitaxy,    wherein the materials ‘A’ and ‘C’ are supplied from an effusion cell and the material ‘B’ is supplied from a plasma source.    
     
     
         4 . The method of  claim 3 , wherein the temperature of the effusion cell is 600˜800°.  
     
     
         5 . The method of  claim 3 , wherein the plasma power is 250˜350 W.  
     
     
         6 . The method of  claim 3 , wherein the doping concentration is in the range of 0.06˜3%.  
     
     
         7 . The method of  claim 3 , wherein the temperature of the substrate is in the range of 300˜1000° C.  
     
     
         8 . A ferromagnetic semiconductor device comprising an insulation layer, a spacer and a ferromagnetic semiconductor sequentially formed on a substrate, 
 the ferromagnetic semiconductor being a 3 group-5 group compound semiconductor comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P,    wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase on the whole.    
     
     
         9 . A ferromagnetic semiconductor device comprising a gate, an insulation layer formed at a lower side of the gate, and a ferromagnetic semiconductor layer formed at a lower side of the insulation layer, 
 the ferromagnetic semiconductor being a 3 group-5 group compound semiconductor comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P,    wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase on the whole.    
     
     
         10 . A ferromagnetic semiconductor device comprising a gate, an insulation layer formed at a lower side of the gate, a source and drain region formed at the left and right side of the insulation layer and using a ferromagnetic semiconductor, and a secondary electron gas layer formed at a lower side of the insulation layer, p 1  the ferromagnetic semiconductor being a 3 group-5 group compound semiconductor comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P, 
 wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase on the whole.  
 
     
     
         11 . A ferromagnetic semiconductor device comprising a seed layer, an anti-ferromagnetic layer, a ferromagnetic semiconductor layer, an insulation layer and a ferromagnetic semiconductor layer sequentially formed on a substrate, 
 the ferromagnetic semiconductor being a 3 group-5 group compound semiconductor comprising one material ‘A’ selected from the group of Ga, Al and In and one material ‘B’ selected from the group consisting of N and P,    wherein one material ‘C’ selected from the group consisting of Mn, Mg, Co, Fe, Ni, Cr and V is doped as a material for substituting the material ‘A’, the compound semiconductor has a single phase on the whole.