JPH04112488A - Manufacture of green light emitting thin film electroluminescence - Google Patents

Abstract

PURPOSE:To obtain a green light emitting thin film electroluminescence element of high luminance by using a binary deposition method where ZnS as a light emitting base material is deposited by a resistance wire heating deposition method, and simultaneously, a mixed pellet of TbF3 and Tb4O7 as the light emitting center is deposited by an electron beam deposition method. CONSTITUTION:ZnS:TbOF, which is formed by a binary deposition method where ZnS as a light emitting base material is deposited by a resistance wire heating deposition method, and simultaneously, a mixed pellet of TbF3 and Tb4O7 as the light emitting center is deposited by an electron beam deposition method, is formed as a green light emitting layer 7 on a first insulator layer 3. Subsequently, a second insulator layer 5 is formed on the green light emitting layer 7 in the same manner as the first insulator layer 3. Furthermore, a back electrode 6 formed by is laminating Al or the like on the second insulator layer 5 by an electron beam deposition method, thus manufacturing a green light emitting thin film electroluminescence(EL) element. It is possible to obtain light emission of high luminance because the TbOF light emitting center is formed in the light emitting center of the green light emitting thin film EL element.

Description

[Detailed description of the invention] "M" L and double M The present invention relates to a method for manufacturing a thin film EL device that emits green light.

Although there are various types of 4U thin film EL devices depending on their structure and voltage application method, an explanation will be given by taking as an example an AC drive type device with a double insulation structure that is currently in practical use. Figure 4 shows its cross-sectional structure. As is well known, this structure consists of a glass substrate 1
A transparent electrode 2 (for example ITO), a first insulating layer 3 (for example Si3N4+Ta203) 9 a light emitting layer 4. Second insulating layer 5
and a back electrode 6 (for example, AI) are sequentially laminated. When an AC voltage is applied from the outside between the transparent electrode 2 and the back electrode 6, the light emitting layer 4 emits light.

Conventionally, when producing a green light-emitting thin film EL device, the light-emitting layer 4 was formed using a binary evaporation method in which a ZnS light-emitting base material and a TbF3 light-emitting center were deposited from separate resistance wire heating evaporation sources.
nS: TbF3 was used (Japanese Patent Application Laid-Open No. 56-10G39
(Japanese Patent Application Laid-Open No. 157888/1988).

However, in the green light emitting thin film EL device using the above method,
There was a problem in that sufficient brightness was not obtained for practical use.

---1 The present invention was proposed to improve the brightness of green light-emitting thin film EL devices, and in forming a light-emitting layer, a binary vapor deposition method is used to simultaneously deposit a light-emitting base material and a light-emitting center. ZnS was deposited as a base material by a resistance wire heating evaporation method, and TbF3 and TbJ were used as luminescent centers.

The method is characterized in that pellets of the mixture are deposited by electron beam evaporation.

According to the method for manufacturing a green light-emitting thin film EL device according to the present invention, there is no clustering, which is an advantage of the conventional binary evaporation method using two resistance wire heating evaporation sources, and uniform doping of the luminescent center is achieved. High brightness can be achieved by newly using the TboF luminescence center as the luminescence center while maintaining the ability to achieve high brightness.

Sharp! up in flames Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the structure of a green light-emitting thin film EL device with double insulation structure and AC drive type manufactured by the method according to an embodiment of the present invention. Components that are the same as those in the conventional example will be described with the same reference numerals. A transparent electrode ITO 2 made of indium oxide and tin oxide is formed on a glass substrate 1, and then Si is deposited as a first insulating layer 3 by vapor deposition, sputtering, CVD, etc.
3N4. It is formed by a single layer or a stack of metal oxides/nitrides such as Ta205. On this first insulating layer 3, ZnS is deposited as a luminescent base material by a resistance wire heating evaporation method,
At the same time, ZnS:Tb0F is formed as a green light-emitting layer 7 using a binary evaporation method in which pellets of a mixture of TbF3 and Tb4O7 are deposited by electron beam evaporation as a luminescent center. Next, the second insulating layer 5 is formed on the green light emitting layer 7 in the same manner as the first insulating layer 3.

Furthermore, a green light-emitting thin film E is formed by laminating the back electrode 6 on the second insulating layer S with AI or the like by electron beam evaporation or the like.
The L element is manufactured.

FIG. 2 shows the brightness-applied voltage characteristics of a green light-emitting thin film EL device of double insulation structure AC drive type manufactured using a light-emitting layer manufactured by the method of the present invention and a light-emitting layer manufactured by the conventional method.

As shown in the figure, the luminance of the device using the light-emitting layer according to the present invention is 1.5 to 2 times higher than that of the conventional device.

The present invention applies not only to the dual insulation structure AC drive type shown in the above embodiments, but also to the monthly supply edge structure in which the first insulation layer is not formed, and the semiconductor substrate shown in FIG.
A green emitting thin film EL element of a direct current drive type in which a green light emitting layer 7 is formed on aAs) 8, and a semiconductor layer (for example Zn5e:Ga) 9 and a transparent electrode (for example Au translucent film) 10 are laminated as thin film layers. May be applied to manufacturing.

As explained above, in forming the light emitting layer of the green light emitting thin film EL device, ZnS is deposited as the light emitting base material by the resistance wire heating evaporation method, and at the same time, TbF3 and Tb4O are used as the light emitting centers.
By using ZnS:Tb0F formed by a binary evaporation method in which pellets of the mixture No. 7 are evaporated by an electron beam evaporation method, a sufficiently high brightness can be obtained for practical use.

[Brief explanation of the drawing]

FIG. 1 is a structural cross-sectional view of a green light emitting thin film EL device manufactured by an embodiment method of the present invention. FIG. 2 is a luminance-applied voltage characteristic diagram of a double insulation structure AC drive type green light emitting thin film EL device manufactured using a light emitting layer according to the method of the present invention and a light emitting layer according to a conventional method. FIG. 3 is a structural sectional view of a direct current drive type green light emitting thin film EL device to which the method of the present invention can be applied. FIG. 4 is a structural sectional view of a thin film EL element of double insulation structure AC drive type for explaining a conventional example. 1... Glass substrate, 2... Transparent electrode, 3... First
Insulating layer, 4... Light emitting layer, 5... Second insulating layer, 6...
- Back electrode, 7... Green light emitting layer, 8... Semiconductor substrate, 9... Semiconductor layer, 10... Transparent electrode. Wealth diagram diagram Kanochoku/wo foot (V) Figure diagram diagram

Claims (1)

[Claims] (1) In forming a light-emitting layer of a thin-film EL device in which a light-emitting layer and at least one thin film layer are sandwiched between a pair of electrodes on a light-transmitting substrate, binary vapor deposition is used to simultaneously deposit a light-emitting base material and a light-emitting center. At that time, ZnS was deposited as a luminescent base material by a resistance wire heating evaporation method, and TbF_3 and Tb_4O_7 were used as luminescent centers.
1. A method for producing a green light-emitting thin film EL, comprising depositing pellets of a mixture thereof by electron beam evaporation.