Thin film semiconductor device having a gate electrode insulator formed through high-heat oxidization

Abstract

A thin film semiconductor device includes a gate electrode insulator formed through high-heat oxidization of a semiconductor film. The high-heat oxidization of semiconductor film is carried out, in the process of crystallization or recrystallization of non-single-crystalline semiconductor thin film on a base layer, by irradiating predetermined areas of the thin film which is implanted with oxygen ion before irradiation, to convert such areas to oxidized areas, and these areas are processed to gate electrode insulators of electric circuit units in the thin film semiconductor device.

What is claimed is:  
     
         1 . A substrate sheet for thin film semiconductor devices comprising: 
 a base layer of insulation materials; and    a thin film semiconductor layer formed on the base layer, said thin film semiconductor layer comprising a layer of crystalline semiconductor grains formed by crystallization or recrystallization of a layer of non-single-crystalline semiconductor and an oxidized layer formed by oxidization of said layer of non-single crystalline semiconductor.    
     
     
         2 . A substrate sheet for thin film semiconductor devices of  claim 1 , wherein a plurality of single-crystalline grains are arranged in a regulated mode in the layer of crystalline semiconductor.  
     
     
         3 . A substrate sheet for thin film semiconductor devices of  claim 1 , wherein the thin oxidized layer formed by oxidation of non-single-crystalline semiconductor layer is formed as a top layer of the thin film semiconductor layer.  
     
     
         4 . A substrate sheet for thin film semiconductor devices of  claim 1 , wherein the thin oxidized layer formed by oxidation of non-single-crystalline semiconductor layer is formed as an intermediate layer in the thin film semiconductor layer.  
     
     
         5 . A substrate sheet for thin film semiconductor devices of  claim 1 , wherein the grain size of single-crystalline semiconductor is at least 2 μm.  
     
     
         6 . A substrate sheet for thin film semiconductor devices of  claim 1 , wherein a control layer for heat-conduction or crystallization is formed between the base layer of insulation material and the thin film semiconductor layer.  
     
     
         7 . A substrate sheet for thin film semiconductor devices of  claim 2 , wherein the thin oxidized layer formed by oxidation of non-single-crystalline semiconductor layer is formed as a top layer of the thin film semiconductor layer.  
     
     
         8 . A substrate sheet for thin film semiconductor devices of  claim 2 , wherein the thin oxidized layer formed by oxidation of non-single-crystalline semiconductor layer is formed as an intermediate layer in the thin film semiconductor layer.  
     
     
         9 . A substrate sheet for thin film semiconductor devices of  claim 2 , wherein the grain size of single-crystalline semiconductor is at least 2 μm.  
     
     
         10 . A substrate sheet for thin film semiconductor devices of  claim 2 , wherein a control layer for heat-conduction or crystallization is formed between the base layer of insulation material and the thin film semiconductor layer.  
     
     
         11 . A thin film semiconductor device comprising; 
 a base layer of insulation materials; and    a thin film semiconductor layer formed on the base layer, said thin film semiconductor layer comprising a layer of semiconductor crystal grains formed by crystallization or recrystallization of non-single-crystalline semiconductor layer and an oxidized layer formed by oxidization of said non-single-crystalline semiconductor layer and, the area of said thin oxidized layer constituting a insulator of gate electrode.    
     
     
         12 . A thin film semiconductor device of  claim 11 , wherein semiconductor crystal grains are arranged in a regulated mode in the layer of single-crystalline semiconductor.  
     
     
         13 . A thin film semiconductor device of  claim 11 , wherein the grain size of single-crystalline semiconductor grains formed in the layer of single-crystalline semiconductor grains is at least 2 μm.  
     
     
         14 . A thin film semiconductor device of  claim 11 , wherein a control layer for heat conduction and recrystallization is formed between the base layer of insulation materials and the thin film semiconductor layer.  
     
     
         15 . A method for producing a substrate sheet for thin film semiconductor devices comprising steps of; 
 (a) depositing a layer of non-single-crystalline semiconductor on a base layer of insulation materials,    (b) forming oxygen implanted areas in the layer of non-single-crystalline by implanting oxygen ion into the layer, and    (c) irradiating the layer of non-single-crystalline semiconductor with energy beam, thereby changing the layer of non-single-crystalline semiconductor so that the oxygen implanted areas are converted to insulating oxidized films and other areas are converted to films of semiconductor crystal grains.    
     
     
         16 . A method for producing a substrate for thin film semiconductor devices of  claim 15 , wherein the irradiation of energy beam is carried out so that the area to which the irradiation intensity of maximum value is given and the area to which the irradiation intensity of minimum value is given are arranged in a regulated mode and the transition of irradiation intensity between the above two areas are successive.  
     
     
         17 . A method for producing a substrate for thin film semiconductor devices of  claim 15 , wherein the minimum value of irradiation intensity the intensity which does not cause the melt of the non-single-crystalline semiconductor.  
     
     
         18 . A method for producing a substrate sheet for thin film semiconductor devices of  claim 15 , wherein the oxygen implanted areas are formed in the top layer portion of non-single-crystalline semiconductor layer.  
     
     
         19 . A method for producing a substrate sheet for thin film semiconductor devices of  claim 15 , wherein the oxygen implanted areas are formed in the intermediate layer portion of non-single-crystalline semiconductor layer.  
     
     
         20 . A method for producing a thin film semiconductor devices comprising steps of; 
 (a) depositing a layer of non-single-crystalline semiconductor on a base layer of insulation materials,    (b) forming oxygen implanted areas in the layer of non-single-crystalline semiconductor by implanting oxygen ion into the layer,    (c) irradiating the layer of non-single-crystalline with energy beam, thereby changing the layer of non-single -crystalline semiconductor so that the oxygen implanted areas are converted to insulating oxidized films and other areas are converted to films of semiconductor crystal grains,    (d) forming a gate electrode by patterning the layer of semiconductor crystal grains and using the insulating oxidized films as a gate insulator and,    (e) completing an electric circuit unit by forming a source electrode and a drain electrode in the layer of semiconductor crystal grains.    
     
     
         21 . A method for producing a thin film semiconductor device of  claim 20 , wherein the irradiation of energy beam is carried out so that the area to which the irradiation intensity of maximum value in given and the area to which the irradiation intensity of are minimum value is given are arranged in a regulated mode and the transition of irradiation intensity between the above two areas are successive.  
     
     
         22 . A method for producing a thin film semiconductor device of  claim 20 , wherein the insulating oxidized layer is formed at the top layer portion of thin film semiconductor layer and, the resulted insulating oxidized layer is used as the gate insulator and the source electrode and the drain electrode are formed in the lower layer of crystal grains.  
     
     
         23 . A method for producing a thin film semiconductor device of  claim 20 , wherein the insulating oxidized layer is formed in the intermediate layer portion of thin film semiconductor layer and, the resulted insulating oxidized layer is used as the gate insulation layer and the source electrode and the drain electrode are formed in the lowest layer of semiconductor grains.