Semiconductor device and method of manufacturing the same

Abstract

On an SOI substrate, a hydrogen ion implantation section in which distribution of hydrogen ions peaks in a BOX layer (buried oxide film layer), and a single-crystal silicon thin-film transistor are formed. Then this SOI substrate is bonded with an insulating substrate. Subsequently, the SOI substrate is cleaved at the hydrogen ion implantation section by carrying out heat treatment, so that an unnecessary part of the SOI substrate is removed, Furthermore, the BOX layer remaining on the single-crystal silicon thin-film transistor is removed by etching. With this, it is possible to from a single-crystal silicon thin-film device on an insulating substrate, without using an adhesive. Moreover, it is possible to provide a semiconductor device which has no surface damage and includes a single-crystal silicon thin film which is thin and uniform in thickness.

1 . A semiconductor device, comprising: 
 an insulating substrate having a surface on which an SiO 2  film is formed; and    a single-crystal silicon substrate bonded with the insulating substrate,    wherein, the single-crystal silicon substrate includes a porous silicon layer and a single-crystal silicon thin film formed on the porous silicon layer and has a surface which is on a single-crystal silicon thin film side with respect to the porous silicon layer and on which an SiO 2  film is formed,    the surface of the insulating substrate, where the SiO 2  film is formed, is bonded with the surface of the single-crystal silicon substrate, where the SiO 2  film is formed, and    a part of the single-crystal silicon substrate is separated at the porous silicon layer, and the porous silicon layer is removed from a remaining part of the single-crystal silicon substrate, the remaining part still being on the insulating substrate after the part is separated.    
     
     
         2 . The semiconductor device as defined in  claim 1 , wherein, in different regions on the insulating substrate, the single-crystal silicon thin film and a non-single-crystal silicon thin film are formed.  
     
     
         3 . The semiconductor device as defined in  claim 1 , wherein the single-crystal silicon thin film is about not more than 70 nm thick.  
     
     
         4 . The semiconductor device as defined in  claim 1 , wherein the single-crystal silicon thin film is about not more than 20 nm thick.  
     
     
         5 . The semiconductor device as defined in  claim 2 , wherein the non-single-crystal silicon thin film comprises polycrystalline silicon.  
     
     
         6 . The semiconductor device as defined in  claim 2 , wherein the non-single-crystal silicon thin film comprises continuous grain silicon.  
     
     
         7 . The semiconductor device as defined in  claim 2 , wherein the non-single-crystal silicon thin film comprises amorphous silicon.  
     
     
         8 . The semiconductor device as defined in  claim 7 , wherein a non-single crystal silicon thin-film transistor, which includes a gate insulating film comprising at least one insulating film including silicon nitride, is formed using the amorphous silicon thin film.  
     
     
         9 . The semiconductor device as defined in  claim 1 , wherein a transistor formed using the single-crystal silicon thin film is arranged such that, from an insulating substrate side, a gate electrode, a gate insulating film, and the single-crystal silicon thin film are formed in this order.  
     
     
         10 . The semiconductor device as defined in  claim 9 , wherein at least a part of the transistor formed using the single-crystal silicon thin film includes an interlayer insulating film and a metal interconnects layer provided further on the single-crystal silicon thin film.  
     
     
         11 . The semiconductor device as defined in  claim 1 , wherein the transistor formed using the single-crystal silicon thin film is arranged such that, from an insulating substrate side, an interlayer insulating film, a metal interconnects layer, an interlayer insulating film, a gate electrode, a gate insulating film, and the single-crystal silicon thin film are formed in this order, and in at least a part of the transistor, an interlayer insulating film and metal interconnects are further provided on the single-crystal silicon thin film.  
     
     
         12 . The semiconductor device as defined in  claim 1 , wherein the insulating substrate comprises a high strain point glass including an alkaline-earth alumino-borosilicate glass.  
     
     
         13 . The semiconductor device as defined in  claim 1 , wherein the insulating substrate comprises any one of a barium borosilicate glass, a barium alumino-borosilicate glass, an alkaline-earth alumino-borosilicate glass, a borosilicate glass, an alkaline-earth-zinc-lead-alumino-borosilicate glass, and an alkaline-earth-lead-alumino-borosilicate glass.  
     
     
         14 . The semiconductor device as defined in  claim 1 , wherein a difference of linear expansion between the insulating substrate and the single-crystal silicon substrate is about not more than 250 ppm at temperatures in a range between substantially room temperatures and 600° C.  
     
     
         15 . The semiconductor device as defined in  claim 1 , wherein the insulating substrate comprises a high strain point glass whose strain point is not less than 500° C.  
     
     
         16 . The semiconductor device as defined in  claim 1 , wherein on a substantially entire surface of the insulating substrate, the single-crystal silicon thin film is formed.  
     
     
         17 . A method of manufacturing a semiconductor device in which a single-crystal silicon substrate is bonded with an insulating substrate having a surface on which an SiO 2  film is formed, comprising the steps of: 
 (i) bonding the surface of the insulating substrate, where the SiO 2  film is formed, with a surface of the single-crystal silicon substrate including a single-crystal silicon thin film formed on a porous silicon layer, the surface of the single-crystal silicon substrate being on a single-crystal silicon thin film side with respect to the porous silicon layer and having an SiO 2  film formed thereon;    (ii) after the step (i), separating a part of the single-crystal silicon substrate at the porous silicon layer; and    (iii) removing the porous silicon layer from a remaining part of the single-crystal silicon substrate, the remaining part still being on the insulating substrate after the step (ii).    
     
     
         18 . The method as defined in  claim 17 , wherein the step (i) is carried out in a vacuum.  
     
     
         19 . The method as defined in  claim 17 , wherein after the step (i), heat treatment is carried out.  
     
     
         20 . The method as defined in  claim 17 , wherein, before the step (i), the single-crystal silicon substrate and the insulating substrate are cleaned and activated.  
     
     
         21 . The method as defined in  claim 20 , wherein the single-crystal silicon substrate and the insulating substrate are cleaned and activated by carrying out RCA (SC-1) clean.