Inorganic EL display insulation media and its making method

Abstract

An inorganic electroluminescent display insulating medium and the manufacturing method comprise: a multi-layer composite thin film A1203 / Ti02 and a AlxTiyOz thin film are manufactured as the medium layer on the ZnS:Mn ACTFEL device through electron beam evaporation method; Bati03 and SrTi03 thin films as the lower medium layer or the electric injection layer of ZnS:Mn ACTFEL device are manufactured and the follow-up annealing temperature of the BaTi03 thin film is reached through the electron evaporation method. The thin films are compared with the SrTi03 and Ba0.55Sr0.5Ti03 thin films manufactured through the traditional sputtering method. The invention optimizes the technique environment of pulse reactive sputtering A1203 thin film, comprising the power, pressure and oxygen content, and is appied to the ZnS:Mn four-pixel devices and the two-inch 128*64 matrix, obtaining better brightness effect. Mediums used in manufacturing the devices comprise Ba0.5Sr0.5TiO3 question mark SrTiO3 question mark BaTiO3 question mark HfO2 question mark Al2O3 question mark Ta2O5 question mark ZrO2 thin films by electron beam evaporation, radio frequency magnetron sputtering or impulse reactive sputtering.

Description

technical field [0001] The invention belongs to the technical field of AC-driven inorganic thin-film electroluminescent display, in particular to a deposition method and an improved process for a medium used in an inorganic thin-film electroluminescent display. Background technique [0002] Electroluminescence refers to the phenomenon that a solid material emits light under the action of a DC or AC electric field, relying on the excitation of current and electric field. Inorganic thin film electroluminescent display (TFEL) has full curing, active luminescence, wide viewing angle (>160°), fast response speed (μs order), large contrast ratio (100:1), high resolution (1000lpi), wide operating temperature (-25-65°C), strong shock resistance, long life (>10 5 h) and other advantages, it is one of the next-generation flat panel display technologies with superior comprehensive performance and wide application prospects. The structure of the TFEL display is usually a MISIM (...

AI Technical Summary

Problems solved by technology

The asymmetric structure is widely used in TDEL and is recognized as very successful. However, there are still many problems in the TFEL device with asymmetric insulating layer: 1) Asymmetric TFEL is a new device structure, the choice of upper and lower dielectric materials , thickness and deposition process need to do a lot of experimental work

3) Although it was reported 15 years ago that SrTiO sputtered by radio frequency magnetron 3 , BaTiO 3 As an insulating layer of TFEL, and optimized process parameters, but has not been applied in production so far

Therefore, it is necessary to try new deposition methods, such as the preparation of epitaxial single crystals, but the preparation of large-area thin films cannot be realized at present and the cost is unacceptable

4) The lower dielectric layer used to maintain polarization is made of high-resistance materials, such as Ta 2 o 5 , It has been confirmed that the device threshold voltage is high and the brightness is low

SrTiO 3 , BaTiO 3 , BST and other perovskite ferroelectric / dielectric films need high-temperature deposition or subsequent annealing to obtain good crystallinity, which will seriously damage the lower dielectric layer and light-emitting layer, and its breakdown mode is generally propagating , so, at least at present, it is difficult to obtain practical application

6) The medium used more frequently in previous work is Y 2 o 3 、Si 3 N 4 、Al 2 o 3 、 Ta 2 o 5 , SiON, SiO 2 , most of them are prepared by electron beam evaporation method, sputtering method or ALD method. However, reports on optimization of deposition process are rare, and these works have certain value for improving the reliability of TFEL devices

7) In the published work, Al 2 o 3 / TiO 2 The composite film is prepared by sputtering, CVD, sol-gel, ALD, ALE and other methods, and the optimization of the film structure and deposition process is not optimized except for the ALD method

[0004] As for the electron injection layer adjacent to the luminescence, Kitai et al. (A.Kitai, K.Cook.Oixde phosphorelectroluminescent laminate.US Pat.6403204, 2002.06.11) believe that it is more advantageous to use a low-resistance medium, such as BaTiO 3 , but earlier work (S.S.Sun.TFEL device having multiplayerinsulators.US Pat.4897319, 1990.01.30) believed that the electron injection layer adjacent to the upper dielectric and the light-emitting layer should use a high-resistance dielectric, such as SiON, which is more favorable. They think The low resistance of the medium in contact with the light-emitting layer will reduce the interface polarization electric field, thereby reducing the luminous efficiency of the device. At the same time, it is found that the use of high-resistance SiON in the lower dielectric layer adjacent to the light-emitting layer will reduce the polarization charge.

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