Magnetic memory device using SOI substrate and method of manufacturing the same

Abstract

A magnetic memory device includes an SOI substrate having a first semiconductor layer, a first insulating film formed on the first semiconductor layer, and a second semiconductor layer formed on the first insulating film, an element isolation insulating film formed selectively in the second semiconductor layer extending from a surface of the second semiconductor layer with a depth reaching the first insulating film, a switching element formed in the second semiconductor layer, a magneto-resistive element connected to the switching element, a first wiring extending in a first direction at a distance below the magneto-resistive element, and a second wiring formed on the magneto-resistive element and extending in a second direction different from the first direction.

1 - 10 . (canceled)  
   
   
       11 . A magnetic memory device comprising: 
 an SOI substrate having a first semiconductor layer, a first insulating film formed on the first semiconductor layer, and a second semiconductor layer formed on the first insulating film;    an element isolation insulating film formed selectively in the second semiconductor layer and extending from a surface of the second semiconductor layer with a depth reaching the first insulating film;    a diode formed in the second semiconductor layer;    a magneto-resistive element connected to the switching element;    a first wiring extending in a first direction at a distance below the magneto-resistive element; and    a second wiring formed on the magneto-resistive element and extending in a second direction different from the first direction,    wherein the diode comprises:    a gate electrode formed on the second semiconductor layer with a gate insulating film interposed;    a first diffusion layer of a first conductivity type that is formed in a portion of the second semiconductor layer, which is located near one end of the gate electrode, the first diffusion layer being connected to the magneto-resistive element; and    a second diffusion layer of a second conductivity type that is formed in a portion of the second semiconductor layer, which is located near the other end of the gate electrode,    wherein a potential to be applied to the gate electrode is variable.    
   
   
       12 . A magnetic memory device comprising: 
 an SOI substrate having a first semiconductor layer a first insulating film formed on the first semiconductor layer, and a second semiconductor layer formed on the first insulating film;    an element isolation insulating film formed selectively in the second semiconductor layer and extending from a surface of the second semiconductor layer with a depth reaching the first insulating film;    a diode formed in the second semiconductor layer;    a magneto-resistive element connected to the switching element;    a first wiring extending in a first direction at a distance below the magneto-resistive element; and    a second wiring formed on the magneto-resistive element and extending in a second direction different from the first direction,    wherein the diode comprises:    a gate electrode formed on the second semiconductor layer with a gate insulating film interposed;    a first diffusion layer of a first conductivity type that is formed in a portion of the second semiconductor layer, which is located near one end of the gate electrode, the first diffusion layer being connected to the magneto-resistive element; and    a second diffusion layer of a second conductivity type that is formed in a portion of the second semiconductor layer, which is located near the other end of the gate electrode,    wherein the second diffusion layer is provided spaced apart from the first diffusion layer.    wherein the second semiconductor layer lying between the first diffusion layer and the second diffusion layer is a third diffusion layer of the first conductivity type or the second conductivity type,    wherein a negative voltage is applied to the gate electrode in a case where the third diffusion layer is of a P type, and a positive voltage is applied to the gate electrode in a case where the third diffusion layer is of an N type.    
   
   
       13 . A magnetic memory device comprising: 
 an SOI substrate having a first semiconductor layer a first insulating film formed on the first semiconductor layer, and a second semiconductor layer formed on the first insulating film;    an element isolation insulating film formed selectively in the second semiconductor layer and extending from a surface of the second semiconductor layer with a depth reaching the first insulating film;    a switching element formed in the second semiconductor layer;    a magneto-resistive element connected to the switching element;    a first wiring extending in a first direction at a distance below the magneto-resistive element; and    a second wiring formed on the magneto-resistive element and extending in a second direction different from the first direction    further comprising a peripheral circuit region formed using a bulk substrate, located at a periphery of a memory cell array region including the magneto-resistive element and the switching element, and having a peripheral circuit controlling the switching element.    
   
   
       14 . A magnetic memory device according to  claim 13 , wherein a surface of the bulk substrate is substantially on a level with a surface of the first semiconductor layer.  
   
   
       15 . A magnetic memory device according to  claim 13 , further comprising: 
 an epitaxial growth layer formed on the bulk substrate, the epitaxial growth layer having a surface that is on a level with a surface of the second semiconductor layer; and    a second insulating film formed between the epitaxial growth layer and the second semiconductor layer.    
   
   
       16 . A magnetic memory device comprising: 
 an SOI substrate having a first semiconductor layer, a first insulating film formed on the first semiconductor layer, and a second semiconductor layer formed on the first insulating film;    an element isolation insulating film formed selectively in the second semiconductor layer extending from a surface of the second semiconductor layer with a depth reaching the first insulating film;    a first switching element formed in the SOI substrate and having one end and the other end;    a second switching element formed in the SOI substrate and having one end and the other end;    a first wiring connected to said one end of the first switching element;    a second wiring connected to said one end of the second switching element;    a third wiring connected to said other end of the first switching element and said other end of the second switching element; and    a magneto-resistive element connected to the third wiring.    
   
   
       17 . A magnetic memory device according to  claim 16 , wherein a direction of magnetization of the magneto-resistive element is inclined 45° with respect to a direction of extension of the third wiring.  
   
   
       18 . A magnetic memory device according to  claim 16 , wherein a gate electrode of the first switching element is a word line for data write and data read-out.  
   
   
       19 . A magnetic memory device according to  claim 16 , wherein a gate electrode of the second switching element is a word line for data write.  
   
   
       20 . A magnetic memory device according to  claim 16 , further comprising a third switching element connected to the magneto-resistive element.  
   
   
       21 . A magnetic memory device according to  claim 20 , wherein a gate electrode of the third switching element is a word line for data read-out.  
   
   
       22 . A magnetic memory device according to  claim 16 , wherein the magneto-resistive element is connected to a ground.  
   
   
       23 . A magnetic memory device according to  claim 16 , wherein each of the first and second switching elements is a transistor or a diode.  
   
   
       24 . A magnetic memory device according to  claim 20 , wherein the third switching element is a transistor or a diode.  
   
   
       25 . A magnetic memory device according to  claim 16 , wherein when data is written in the magneto-resistive element, the first and second switching elements are turned on to let a current flow between the first and second wirings.  
   
   
       26 . A magnetic memory device according to  claim 25 , further comprising a third switching element connected to the magneto-resistive element, wherein the third switching element is turned off when the data is written.  
   
   
       27 . A magnetic memory device according to  claim 16 , wherein when data is read out from the magneto-resistive element, the first switching element is turned on and the second switching element is turned off to let a current flow from the first wiring to the magneto-resistive element.  
   
   
       28 . A magnetic memory device according to  claim 27 , further comprising a third switching element connected to the magneto-resistive element, wherein the third switching element is turned on when the data is read out.  
   
   
       29 - 48 . (canceled)