MIM is a sandwich structure composed of a metal, insulator, and metal three-layer film. The MIM structure for liquid crystal display is shown in Figure 1, mainly
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There are two types: (1) Figure 1 (a) is a relatively common "T" shape structure. The process of this structure is relatively simple, and the MIM developed in the early stage is basically this form. However, the MIM area of this structure is relatively large and has a large parasitic
Capacitance is detrimental to improving contrast and improving display quality. If you want to reduce the area, you need a large area, high resolution
Lithographic equipment. Not only increases the difficulty of the production process, the yield rate decreases, but also increases the cost, and is not suitable for large scale.
display. (2) Figure 1 (b) shows the lateral MIM structure developed, which is formed laterally on the scan line.
MIM decisive action
The M IM component is characterized by a non-linear change in its volt-ampere characteristics. LCD display is the use of this feature of MIM. When the applied bias voltage is reached
When a certain value V (closed voltage), the conductivity of the MIM changes abruptly and changes from the insulated state to the conductor state. Electricity through MIM
The flow also increases rapidly. MIM is in the "on" state. When the applied bias voltage on the MIM is less than VT, the MIM returns to its original state, MIM.
In the "lizard" state. The insulation properties of the insulation are not damaged throughout the "pass," "lizard" process. Figure 2 shows the Volt of MrM
Sex curve.
MIMI communication mechanism
Therefore, under the action of a strong field, a large amount of electrons on the donor level enter the insulating layer conduction band. And avalanche breakdown occurs under the action of a strong field. The relationship between its volt-ampere characteristics can be expressed by the formula (1). For the MIM whose insulation layer is Ta zO, the 13 PF value of the MIM obtained in actual work does not conform to the PooIe-Frenkel3L~ value and conforms to Schottky's
The theoretical value is s (13 PF = 2 13 s). This abnormal Poole-Frenke1 effect occurs mainly in the Ta zO film.
There is only a neutral trap level, so the Poole-F reakel effect cannot be shown. And the conductivity at this time
Also very low In order to solve this problem, deep donor energy must be formed in the Ta:O film by heat treatment and other processes.
Level to meet the requirements of liquid crystal display. Partially unbalanced defects can also be removed during processing.
Improve the stability of MIM.
