Light emitting device and manufacturing method thereof

Abstract

A light emitting element having an organic compound, which can be extended its longevity is provided. According to the present invention, there is provided a constitution in which, in order to protect a light emitting element from moisture, an inorganic insulating film 312a, a stress relaxation layer 312b having transparency and a hygroscopic property, and an inorganic insulating film 312c are repeatedly laminated over a cathode. The stress relaxation layer 312b having transparency and the hygroscopic property uses at least one film selected from the group consisting of a film comprising a same material as that of a layer 310, containing an organic compound, sandwiched between a cathode and an anode, a layer capable of being formed by vapor deposition, and a layer capable of being formed by coating.

1 . (canceled) 
     
     
         2 . A light emitting device comprising:
 a first substrate;   a light emitting element over the first substrate, the light emitting element comprising:
 an anode over the first substrate; 
 an electroluminescent layer over the anode; and 
 a cathode over the electroluminescent layer; 
   a first film over and in direct contact with the cathode; and   a second film over and in direct contact with the first film,   wherein each of the electroluminescent layer and the first film comprises a first organic compound, and   wherein the second film comprises an inorganic insulating material comprising silicon and one of oxygen and nitrogen.   
     
     
         3 . The light emitting device according to  claim 2 ,
 wherein the electroluminescent layer comprises a hole transport layer, and   wherein the hole transport layer comprises the first organic compound.   
     
     
         4 . The light emitting device according to  claim 3 , wherein the first organic compound is 4,4′-bis[N-(naphthyl)-N-phenyl-amino]biphenyl. 
     
     
         5 . The light emitting device according to  claim 2 ,
 wherein the electroluminescent layer comprises a electron transport layer, and   wherein the electron transport layer comprises the first organic compound.   
     
     
         6 . The light emitting device according to  claim 5 , wherein the first organic compound is tris-8-quinolinolate aluminum complex. 
     
     
         7 . The light emitting device according to  claim 2 , wherein each of the first film is formed by vapor deposition. 
     
     
         8 . The light emitting device according to  claim 2 , wherein the light emitting element emits mono-color luminescence of red, green or blue. 
     
     
         9 . The light emitting device according to  claim 2 , wherein the light emitting device is a full-color display. 
     
     
         10 . A semiconductor device comprising the light emitting device according to  claim 2 , wherein the semiconductor device is at least one selected from the group consisting of a video camera, a digital camera, a display, a car navigation system, a personal computer and a portable information terminal. 
     
     
         11 . A light emitting device comprising:
 a first substrate;   a light emitting element over the first substrate, the light emitting element comprising:
 an anode over the first substrate; 
 a hole transport layer over the anode; 
 a light emitting layer over the hole transport layer; 
 an electron transport layer over the light emitting layer; and 
 a cathode over the electron transport layer; 
   a first film over and in direct contact with the cathode; and   a second film over and in direct contact with the first film,   wherein each of the hole transport layer and the first film comprises a first organic compound, and   wherein the second film comprises an inorganic insulating material comprising silicon and one of oxygen and nitrogen.   
     
     
         12 . The light emitting device according to  claim 11 , wherein the first organic compound is 4,4′-bis[N-(naphthyl)-N-phenyl-amino]biphenyl. 
     
     
         13 . The light emitting device according to  claim 11 , wherein the second film is one of a silicon oxide film, a silicon oxynitride film, a SiON film and a silicon nitride film. 
     
     
         14 . The light emitting device according to  claim 11 , further comprising a hole injection layer. 
     
     
         15 . A light emitting device comprising:
 a first substrate;   a light emitting element over the first substrate, the light emitting element comprising:
 an anode over the first substrate; 
 a hole transport layer over the anode; 
 a light emitting layer over the hole transport layer; 
 an electron transport layer over the light emitting layer; and 
 a cathode over the electron transport layer; 
   a first film over and in direct contact with the cathode; and   a second film over and in direct contact with the first film,   wherein each of the electron transport layer and the first film comprises a first organic compound, and   wherein the second film comprises an inorganic insulating material comprising silicon and one of oxygen and nitrogen.   
     
     
         16 . The light emitting device according to  claim 15 , wherein the first organic compound is tris-8-quinolinolate aluminum complex. 
     
     
         17 . The light emitting device according to  claim 15 , wherein the second film is one of a silicon oxide film, a silicon oxynitride film, a SiON film and a silicon nitride film. 
     
     
         18 . The light emitting device according to  claim 15 , further comprising an electron injection layer.